Merge branch 'develop' into hotfix/TD-476

fe5ebec9 · Shengliang Guan · GitHub · 75b1980f · 3c7b4637 · fe5ebec9
77 changed file
--- a/src/client/inc/tscUtil.h
+++ b/src/client/inc/tscUtil.h
@@ -132,10 +132,7 @@ bool tscIsSelectivityWithTagQuery(SSqlCmd* pCmd);
 void tscAddSpecialColumnForSelect(SQueryInfo* pQueryInfo, int32_t outputColIndex, int16_t functionId, SColumnIndex* pIndex,
                                  SSchema* pColSchema, int16_t isTag);
-//void addRequiredTagColumn(SQueryInfo* pQueryInfo, int32_t tagColIndex, int32_t tableIndex);
+int32_t tscSetTableFullName(STableMetaInfo* pTableMetaInfo, SSQLToken* pzTableName, SSqlObj* pSql);
-void addRequiredTagColumn(STableMetaInfo* pTableMetaInfo, SColumnIndex* index);
-int32_t tscSetTableId(STableMetaInfo* pTableMetaInfo, SSQLToken* pzTableName, SSqlObj* pSql);
 void    tscClearInterpInfo(SQueryInfo* pQueryInfo);
 bool tscIsInsertData(char* sqlstr);

--- a/src/client/inc/tsclient.h
+++ b/src/client/inc/tsclient.h
@@ -294,7 +294,6 @@ typedef struct STscObj {
  char               sversion[TSDB_VERSION_LEN];
  char               writeAuth : 1;
  char               superAuth : 1;
-  struct SSqlObj *   pSql;
  struct SSqlObj *   pHb;
  struct SSqlObj *   sqlList;
  struct SSqlStream *streamList;
@@ -411,7 +410,7 @@ void doAsyncQuery(STscObj *pObj, SSqlObj *pSql, void (*fp)(), void *param, const
 void tscProcessMultiVnodesInsertFromFile(SSqlObj *pSql);
 void tscKillSTableQuery(SSqlObj *pSql);
 void tscInitResObjForLocalQuery(SSqlObj *pObj, int32_t numOfRes, int32_t rowLen);
-bool tscIsUpdateQuery(STscObj *pObj);
+bool tscIsUpdateQuery(SSqlObj* pSql);
 bool tscHasReachLimitation(SQueryInfo *pQueryInfo, SSqlRes *pRes);
 char *tscGetErrorMsgPayload(SSqlCmd *pCmd);

--- a/src/client/jni/com_taosdata_jdbc_TSDBJNIConnector.h
+++ b/src/client/jni/com_taosdata_jdbc_TSDBJNIConnector.h
@@ -62,7 +62,7 @@ JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_connectImp
 * Method:    executeQueryImp
 * Signature: ([BJ)I
 */
-JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_executeQueryImp
+JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_executeQueryImp
  (JNIEnv *, jobject, jbyteArray, jlong);
 /*
@@ -71,7 +71,7 @@ JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_executeQueryImp
 * Signature: (J)I
 */
 JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getErrCodeImp
-  (JNIEnv *, jobject, jlong);
+  (JNIEnv *, jobject, jlong, jlong);
 /*
 * Class:     com_taosdata_jdbc_TSDBJNIConnector
@@ -87,7 +87,7 @@ JNIEXPORT jstring JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getErrMsgImp
 * Signature: (J)J
 */
 JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getResultSetImp
-  (JNIEnv *, jobject, jlong);
+  (JNIEnv *env, jobject jobj, jlong con, jlong tres);
 /*
 * Class:     com_taosdata_jdbc_TSDBJNIConnector
@@ -103,7 +103,7 @@ JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_freeResultSetImp
 * Signature: (J)I
 */
 JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getAffectedRowsImp
-  (JNIEnv *, jobject, jlong);
+  (JNIEnv *env, jobject jobj, jlong con, jlong res);
 /*
 * Class:     com_taosdata_jdbc_TSDBJNIConnector
@@ -142,8 +142,8 @@ JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_subscribeImp
 * Method:    consumeImp
 * Signature: (J)Lcom/taosdata/jdbc/TSDBResultSetRowData;
 */
-JNIEXPORT jobject JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_consumeImp
+JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_consumeImp
-  (JNIEnv *, jobject, jlong, jint);
+  (JNIEnv *, jobject, jlong);
 /*
 * Class:     com_taosdata_jdbc_TSDBJNIConnector

--- a/src/client/src/TSDBJNIConnector.c
+++ b/src/client/src/TSDBJNIConnector.c
@@ -13,19 +13,35 @@
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
-#include "com_taosdata_jdbc_TSDBJNIConnector.h"
 #include "os.h"
 #include "taos.h"
-#include "tscSubquery.h"
+#include "tlog.h"
 #include "tscUtil.h"
 #include "tsclient.h"
-#include "tlog.h"
 #include "ttime.h"
-#define jniError(...)  { if (jniDebugFlag & DEBUG_ERROR) { taosPrintLog("ERROR JNI ", jniDebugFlag, __VA_ARGS__); }}
+#include "com_taosdata_jdbc_TSDBJNIConnector.h"
-#define jniWarn(...)   { if (jniDebugFlag & DEBUG_WARN)  { taosPrintLog("WARN JNI ", jniDebugFlag, __VA_ARGS__); }}
-#define jniTrace(...)  { if (jniDebugFlag & DEBUG_TRACE) { taosPrintLog("JNI ", jniDebugFlag, __VA_ARGS__); }}
+#define jniError(...)                                        \
-#define jniPrint(...)  { taosPrintLog("JNI ", tscEmbedded ? 255 : uDebugFlag, __VA_ARGS__); }
+  {                                                          \
+    if (jniDebugFlag & DEBUG_ERROR) {                        \
+      taosPrintLog("ERROR JNI ", jniDebugFlag, __VA_ARGS__); \
+    }                                                        \
+  }
+#define jniWarn(...)                                        \
+  {                                                         \
+    if (jniDebugFlag & DEBUG_WARN) {                        \
+      taosPrintLog("WARN JNI ", jniDebugFlag, __VA_ARGS__); \
+    }                                                       \
+  }
+#define jniTrace(...)                                  \
+  {                                                    \
+    if (jniDebugFlag & DEBUG_TRACE) {                  \
+      taosPrintLog("JNI ", jniDebugFlag, __VA_ARGS__); \
+    }                                                  \
+  }
+#define jniPrint(...) \
+  { taosPrintLog("JNI ", tscEmbedded ? 255 : uDebugFlag, __VA_ARGS__); }
 int __init = 0;
@@ -117,7 +133,8 @@ void jniGetGlobalMethod(JNIEnv *env) {
  jniTrace("native method register finished");
 }
-JNIEXPORT void JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_setAllocModeImp(JNIEnv *env, jobject jobj, jint jMode, jstring jPath, jboolean jAutoDump) {
+JNIEXPORT void JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_setAllocModeImp(JNIEnv *env, jobject jobj, jint jMode,
+                                                                               jstring jPath, jboolean jAutoDump) {
  if (jPath != NULL) {
    const char *path = (*env)->GetStringUTFChars(env, jPath, NULL);
    taosSetAllocMode(jMode, path, !!jAutoDump);
@@ -172,14 +189,14 @@ JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_setOptions(JNIEnv
    }
    (*env)->ReleaseStringUTFChars(env, optionValue, charset);
  } else if (optionIndex == TSDB_OPTION_TIMEZONE) {
-    const char *timezone = (*env)->GetStringUTFChars(env, optionValue, NULL);
+    const char *tz1 = (*env)->GetStringUTFChars(env, optionValue, NULL);
-    if (timezone && strlen(timezone) != 0) {
+    if (tz1 && strlen(tz1) != 0) {
-      res = taos_options(TSDB_OPTION_TIMEZONE, timezone);
+      res = taos_options(TSDB_OPTION_TIMEZONE, tz1);
      jniTrace("set timezone to %s, result:%d", timezone, res);
    } else {
      jniTrace("input timezone is empty");
    }
-    (*env)->ReleaseStringUTFChars(env, optionValue, timezone);
+    (*env)->ReleaseStringUTFChars(env, optionValue, tz1);
  } else {
    jniError("option index:%d is not found", optionIndex);
  }
@@ -219,9 +236,9 @@ JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_connectImp(JNIEn
  }
  /*
-  * set numOfThreadsPerCore = 0
+   * set numOfThreadsPerCore = 0
-  * means only one thread for client side scheduler
+   * means only one thread for client side scheduler
-  */
+   */
  tsNumOfThreadsPerCore = 0.0;
  ret = (jlong)taos_connect((char *)host, (char *)user, (char *)pass, (char *)dbname, jport);
@@ -241,8 +258,8 @@ JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_connectImp(JNIEn
  return ret;
 }
-JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_executeQueryImp(JNIEnv *env, jobject jobj,
+JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_executeQueryImp(JNIEnv *env, jobject jobj,
-                                                                               jbyteArray jsql, jlong con) {
+                                                                                jbyteArray jsql, jlong con) {
  TAOS *tscon = (TAOS *)con;
  if (tscon == NULL) {
    jniError("jobj:%p, connection is already closed", jobj);
@@ -264,65 +281,76 @@ JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_executeQueryImp(J
  (*env)->GetByteArrayRegion(env, jsql, 0, len, (jbyte *)dst);
  if ((*env)->ExceptionCheck(env)) {
-    //todo handle error
+    // todo handle error
  }
  jniTrace("jobj:%p, conn:%p, sql:%s", jobj, tscon, dst);
-  int code = taos_query(tscon, dst);
+  SSqlObj *pSql = taos_query(tscon, dst);
-  if (code != 0) {
+  int32_t  code = taos_errno(pSql);
-    jniError("jobj:%p, conn:%p, code:%s, msg:%s", jobj, tscon, tstrerror(code), taos_errstr(tscon));
-    free(dst);
-    return JNI_TDENGINE_ERROR;
-  } else {
-    int32_t  affectRows = 0;
-    SSqlObj *pSql = ((STscObj *)tscon)->pSql;
+  if (code != TSDB_CODE_SUCCESS) {
+    jniError("jobj:%p, conn:%p, code:%s, msg:%s", jobj, tscon, tstrerror(code), taos_errstr(pSql));
+  } else {
+    int32_t affectRows = 0;
    if (pSql->cmd.command == TSDB_SQL_INSERT) {
-      affectRows = taos_affected_rows(tscon);
+      affectRows = taos_affected_rows(pSql);
      jniTrace("jobj:%p, conn:%p, code:%s, affect rows:%d", jobj, tscon, tstrerror(code), affectRows);
    } else {
      jniTrace("jobj:%p, conn:%p, code:%s", jobj, tscon, tstrerror(code));
    }
-    free(dst);
-    return affectRows;
  }
+  free(dst);
+  return (jlong)pSql;
 }
-JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getErrCodeImp(JNIEnv *env, jobject jobj, jlong con) {
+JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getErrCodeImp(JNIEnv *env, jobject jobj, jlong con, jlong tres) {
  TAOS *tscon = (TAOS *)con;
  if (tscon == NULL) {
    jniError("jobj:%p, connection is closed", jobj);
-    return (jint)-TSDB_CODE_INVALID_CONNECTION;
+    return (jint)TSDB_CODE_INVALID_CONNECTION;
  }
-  return (jint)-taos_errno(tscon);
+  if ((void *)tres == NULL) {
+    jniError("jobj:%p, conn:%p, resultset is null", jobj, tscon);
+    return JNI_RESULT_SET_NULL;
+  }
+  TAOS_RES *pSql = (TAOS_RES *)tres;
+  return (jint)taos_errno(pSql);
 }
-JNIEXPORT jstring JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getErrMsgImp(JNIEnv *env, jobject jobj, jlong con) {
+JNIEXPORT jstring JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getErrMsgImp(JNIEnv *env, jobject jobj, jlong tres) {
-  TAOS *tscon = (TAOS *)con;
+  TAOS_RES *pSql = (TAOS_RES *)tres;
-  return (*env)->NewStringUTF(env, (const char *)taos_errstr(tscon));
+  return (*env)->NewStringUTF(env, (const char *)taos_errstr(pSql));
 }
-JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getResultSetImp(JNIEnv *env, jobject jobj, jlong con) {
+JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getResultSetImp(JNIEnv *env, jobject jobj, jlong con,
+                                                                                jlong tres) {
  TAOS *tscon = (TAOS *)con;
  if (tscon == NULL) {
    jniError("jobj:%p, connection is closed", jobj);
    return JNI_CONNECTION_NULL;
  }
-  jlong ret = 0;
+  if ((void *)tres == NULL) {
+    jniError("jobj:%p, conn:%p, resultset is null", jobj, tscon);
+    return JNI_RESULT_SET_NULL;
+  }
+  SSqlObj *pSql = (TAOS_RES *)tres;
+  STscObj *pObj = pSql->pTscObj;
-  if (tscIsUpdateQuery(tscon)) {
+  if (tscIsUpdateQuery(pSql)) {
-    ret = 0;  // for update query, no result pointer
+    taos_free_result(pSql);  // free result here
-    jniTrace("jobj:%p, conn:%p, no resultset", jobj, tscon);
+    jniTrace("jobj:%p, conn:%p, no resultset, %p", jobj, pObj, (void *)tres);
+    return 0;
  } else {
-    ret = (jlong) taos_use_result(tscon);
+    jniTrace("jobj:%p, conn:%p, get resultset, %p", jobj, pObj, (void *)tres);
-    jniTrace("jobj:%p, conn:%p, get resultset:%p", jobj, tscon, (void *) ret);
+    return tres;
  }
-  return ret;
 }
 JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_freeResultSetImp(JNIEnv *env, jobject jobj, jlong con,
@@ -343,17 +371,21 @@ JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_freeResultSetImp(
  return JNI_SUCCESS;
 }
-JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getAffectedRowsImp(JNIEnv *env, jobject jobj,
+JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getAffectedRowsImp(JNIEnv *env, jobject jobj, jlong con,
-                                                                                  jlong con) {
+                                                                                  jlong res) {
  TAOS *tscon = (TAOS *)con;
  if (tscon == NULL) {
    jniError("jobj:%p, connection is closed", jobj);
    return JNI_CONNECTION_NULL;
  }
-  jint ret = taos_affected_rows(tscon);
+  if ((void *)res == NULL) {
+    jniError("jobj:%p, conn:%p, resultset is null", jobj, tscon);
+    return JNI_RESULT_SET_NULL;
+  }
-  jniTrace("jobj:%p, conn:%p, affect rows:%d", jobj, tscon, (void *)con, ret);
+  jint ret = taos_affected_rows((SSqlObj *)res);
+  jniTrace("jobj:%p, conn:%p, sql:%p, affect rows:%d", jobj, tscon, (void *)con, res, ret);
  return ret;
 }
@@ -405,7 +437,7 @@ JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getSchemaMetaData
 * @return
 */
 jstring jniFromNCharToByteArray(JNIEnv *env, char *nchar, int32_t maxBytes) {
-  int        len = (int)strlen(nchar);
+  int len = (int)strlen(nchar);
  if (len > maxBytes) {  // no terminated symbol exists '\0'
    len = maxBytes;
  }
@@ -439,7 +471,7 @@ JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_fetchRowImp(JNIEn
  TAOS_ROW row = taos_fetch_row(result);
  if (row == NULL) {
-    int tserrno = taos_errno(tscon);
+    int tserrno = taos_errno(result);
    if (tserrno == 0) {
      jniTrace("jobj:%p, conn:%p, resultset:%p, fields size is %d, fetch row to the end", jobj, tscon, res, num_fields);
      return JNI_FETCH_END;
@@ -476,24 +508,22 @@ JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_fetchRowImp(JNIEn
        float fv = 0;
        fv = GET_FLOAT_VAL(row[i]);
        (*env)->CallVoidMethod(env, rowobj, g_rowdataSetFloatFp, i, (jfloat)fv);
-      }
+      } break;
-        break;
      case TSDB_DATA_TYPE_DOUBLE: {
        double dv = 0;
        dv = GET_DOUBLE_VAL(row[i]);
        (*env)->CallVoidMethod(env, rowobj, g_rowdataSetDoubleFp, i, (jdouble)dv);
-      }
+      } break;
-        break;
      case TSDB_DATA_TYPE_BINARY: {
-        strncpy(tmp, row[i], (size_t) fields[i].bytes);  // handle the case that terminated does not exist
+        strncpy(tmp, row[i], (size_t)fields[i].bytes);  // handle the case that terminated does not exist
        (*env)->CallVoidMethod(env, rowobj, g_rowdataSetStringFp, i, (*env)->NewStringUTF(env, tmp));
-        memset(tmp, 0, (size_t) fields[i].bytes);
+        memset(tmp, 0, (size_t)fields[i].bytes);
        break;
      }
      case TSDB_DATA_TYPE_NCHAR: {
        (*env)->CallVoidMethod(env, rowobj, g_rowdataSetByteArrayFp, i,
-                               jniFromNCharToByteArray(env, (char*)row[i], fields[i].bytes));
+                               jniFromNCharToByteArray(env, (char *)row[i], fields[i].bytes));
        break;
      }
      case TSDB_DATA_TYPE_TIMESTAMP:
@@ -552,7 +582,7 @@ JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_subscribeImp(JNI
  return sub;
 }
-static jobject convert_one_row(JNIEnv *env, TAOS_ROW row, TAOS_FIELD* fields, int num_fields) {
+static jobject convert_one_row(JNIEnv *env, TAOS_ROW row, TAOS_FIELD *fields, int num_fields) {
  jobject rowobj = (*env)->NewObject(env, g_rowdataClass, g_rowdataConstructor, num_fields);
  jniTrace("created a rowdata object, rowobj:%p", rowobj);
@@ -581,25 +611,23 @@ static jobject convert_one_row(JNIEnv *env, TAOS_ROW row, TAOS_FIELD* fields, in
        float fv = 0;
        fv = GET_FLOAT_VAL(row[i]);
        (*env)->CallVoidMethod(env, rowobj, g_rowdataSetFloatFp, i, (jfloat)fv);
-      }
+      } break;
-        break;
+      case TSDB_DATA_TYPE_DOUBLE: {
-      case TSDB_DATA_TYPE_DOUBLE:{
        double dv = 0;
        dv = GET_DOUBLE_VAL(row[i]);
        (*env)->CallVoidMethod(env, rowobj, g_rowdataSetDoubleFp, i, (jdouble)dv);
-      }
+      } break;
-        break;
      case TSDB_DATA_TYPE_BINARY: {
        char tmp[TSDB_MAX_BYTES_PER_ROW] = {0};
-        strncpy(tmp, row[i], (size_t) fields[i].bytes);  // handle the case that terminated does not exist
+        strncpy(tmp, row[i], (size_t)fields[i].bytes);  // handle the case that terminated does not exist
        (*env)->CallVoidMethod(env, rowobj, g_rowdataSetStringFp, i, (*env)->NewStringUTF(env, tmp));
-        memset(tmp, 0, (size_t) fields[i].bytes);
+        memset(tmp, 0, (size_t)fields[i].bytes);
        break;
      }
      case TSDB_DATA_TYPE_NCHAR:
        (*env)->CallVoidMethod(env, rowobj, g_rowdataSetByteArrayFp, i,
-                              jniFromNCharToByteArray(env, (char*)row[i], fields[i].bytes));
+                               jniFromNCharToByteArray(env, (char *)row[i], fields[i].bytes));
        break;
      case TSDB_DATA_TYPE_TIMESTAMP:
        (*env)->CallVoidMethod(env, rowobj, g_rowdataSetTimestampFp, i, (jlong) * ((int64_t *)row[i]));
@@ -611,51 +639,27 @@ static jobject convert_one_row(JNIEnv *env, TAOS_ROW row, TAOS_FIELD* fields, in
  return rowobj;
 }
-JNIEXPORT jobject JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_consumeImp(JNIEnv *env, jobject jobj, jlong sub, jint timeout) {
+JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_consumeImp(JNIEnv *env, jobject jobj, jlong sub) {
  jniTrace("jobj:%p, in TSDBJNIConnector_consumeImp, sub:%ld", jobj, sub);
  jniGetGlobalMethod(env);
  TAOS_SUB *tsub = (TAOS_SUB *)sub;
-  jobject   rows = (*env)->NewObject(env, g_arrayListClass, g_arrayListConstructFp);
  int64_t start = taosGetTimestampMs();
  int count = 0;
-  while (true) {
+  TAOS_RES *res = taos_consume(tsub);
-    TAOS_RES *  res = taos_consume(tsub);
-    if (res == NULL) {
-      jniError("jobj:%p, tsub:%p, taos_consume returns NULL", jobj, tsub);
-      return NULL;
-    }
-    TAOS_FIELD *fields = taos_fetch_fields(res);
+  if (res == NULL) {
-    int         num_fields = taos_num_fields(res);
+    jniError("jobj:%p, tsub:%p, taos_consume returns NULL", jobj, tsub);
-    while (true) {
+    return NULL;
-      TAOS_ROW row = taos_fetch_row(res);
-      if (row == NULL) {
-        break;
-      }
-      jobject rowobj = convert_one_row(env, row, fields, num_fields);
-      (*env)->CallBooleanMethod(env, rows, g_arrayListAddFp, rowobj);
-      count++;
-    }
-    if (count > 0) {
-      break;
-    }
-    if (timeout == -1) {
-      continue;
-    }
-    if (((int)(taosGetTimestampMs() - start)) >= timeout) {
-      jniTrace("jobj:%p, sub:%ld, timeout", jobj, sub);
-      break;
-    }
  }
-  return rows;
+  return res;
 }
-JNIEXPORT void JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_unsubscribeImp(JNIEnv *env, jobject jobj, jlong sub, jboolean keepProgress) {
+JNIEXPORT void JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_unsubscribeImp(JNIEnv *env, jobject jobj, jlong sub,
+                                                                              jboolean keepProgress) {
  TAOS_SUB *tsub = (TAOS_SUB *)sub;
  taos_unsubscribe(tsub, keepProgress);
 }
@@ -678,7 +682,7 @@ JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_validateCreateTab
  char *dst = (char *)calloc(1, sizeof(char) * (len + 1));
  (*env)->GetByteArrayRegion(env, jsql, 0, len, (jbyte *)dst);
  if ((*env)->ExceptionCheck(env)) {
-    //todo handle error
+    // todo handle error
  }
  int code = taos_validate_sql(tscon, dst);

--- a/src/client/src/tscAsync.c
+++ b/src/client/src/tscAsync.c
@@ -50,14 +50,15 @@ void doAsyncQuery(STscObj* pObj, SSqlObj* pSql, void (*fp)(), void* param, const
  pSql->maxRetry  = TSDB_MAX_REPLICA_NUM;
  pSql->fp        = fp;
+  sem_init(&pSql->rspSem, 0, 0);
  if (TSDB_CODE_SUCCESS != tscAllocPayload(pCmd, TSDB_DEFAULT_PAYLOAD_SIZE)) {
    tscError("failed to malloc payload");
    tscQueueAsyncError(fp, param, TSDB_CODE_CLI_OUT_OF_MEMORY);
    return;
  }
-  pSql->sqlstr = realloc(pSql->sqlstr, sqlLen + 1);
+  // todo check for OOM problem
+  pSql->sqlstr = calloc(1, sqlLen + 1);
  if (pSql->sqlstr == NULL) {
    tscError("%p failed to malloc sql string buffer", pSql);
    tscQueueAsyncError(fp, param, TSDB_CODE_CLI_OUT_OF_MEMORY);
@@ -95,7 +96,7 @@ void taos_query_a(TAOS *taos, const char *sqlstr, __async_cb_func_t fp, void *pa
  int32_t sqlLen = strlen(sqlstr);
  if (sqlLen > tsMaxSQLStringLen) {
-    tscError("sql string too long");
+    tscError("sql string exceeds max length:%d", tsMaxSQLStringLen);
    terrno = TSDB_CODE_INVALID_SQL;
    tscQueueAsyncError(fp, param, TSDB_CODE_INVALID_SQL);
    return;
@@ -486,7 +487,7 @@ void tscTableMetaCallBack(void *param, TAOS_RES *res, int code) {
          STableMetaInfo* pTableMetaInfo = tscGetTableMetaInfoFromCmd(pCmd, pCmd->clauseIndex, 0);
          code = tscGetTableMeta(pSql, pTableMetaInfo);
          assert(code == TSDB_CODE_SUCCESS && pTableMetaInfo->pTableMeta != NULL);
-          (*pSql->fp)(pSql->param, NULL, code);
+          (*pSql->fp)(pSql->param, pSql, code);
          return;
        }

--- a/src/client/src/tscParseInsert.c
+++ b/src/client/src/tscParseInsert.c
@@ -793,7 +793,7 @@ static int32_t tscCheckIfCreateTable(char **sqlstr, SSqlObj *pSql) {
    }
    STableMetaInfo *pSTableMeterMetaInfo = tscGetMetaInfo(pQueryInfo, STABLE_INDEX);
-    tscSetTableId(pSTableMeterMetaInfo, &sToken, pSql);
+    tscSetTableFullName(pSTableMeterMetaInfo, &sToken, pSql);
    strncpy(pTag->name, pSTableMeterMetaInfo->name, TSDB_TABLE_ID_LEN);
    code = tscGetTableMeta(pSql, pSTableMeterMetaInfo);
@@ -834,9 +834,8 @@ static int32_t tscCheckIfCreateTable(char **sqlstr, SSqlObj *pSql) {
        sql += index;
        if (TK_STRING == sToken.type) {
-          sToken.n = strdequote(sToken.z);
+          strdequote(sToken.z);
-          strtrim(sToken.z);
+          sToken.n = strtrim(sToken.z);
-          sToken.n = (uint32_t)strlen(sToken.z);
        }
        if (sToken.type == TK_RP) {
@@ -925,7 +924,11 @@ static int32_t tscCheckIfCreateTable(char **sqlstr, SSqlObj *pSql) {
      for (int32_t i = 0; i < spd.numOfCols; ++i) {
        if (!spd.hasVal[i]) {  // current tag column do not have any value to insert, set it to null
-          setNull(ptr, pTagSchema[i].type, pTagSchema[i].bytes);
+          if (pTagSchema[i].type == TSDB_DATA_TYPE_BINARY || pTagSchema[i].type == TSDB_DATA_TYPE_NCHAR) {
+            setVardataNull(ptr, pTagSchema[i].type);
+          } else {
+            setNull(ptr, pTagSchema[i].type, pTagSchema[i].bytes);
+          }
        }
        ptr += pTagSchema[i].bytes;
@@ -944,7 +947,7 @@ static int32_t tscCheckIfCreateTable(char **sqlstr, SSqlObj *pSql) {
      return tscInvalidSQLErrMsg(pCmd->payload, "invalid table name", *sqlstr);
    }
-    int32_t ret = tscSetTableId(pTableMetaInfo, &tableToken, pSql);
+    int32_t ret = tscSetTableFullName(pTableMetaInfo, &tableToken, pSql);
    if (ret != TSDB_CODE_SUCCESS) {
      return ret;
    }
@@ -1087,7 +1090,7 @@ int doParseInsertSql(SSqlObj *pSql, char *str) {
      goto _error_clean;
    }
-    if ((code = tscSetTableId(pTableMetaInfo, &sToken, pSql)) != TSDB_CODE_SUCCESS) {
+    if ((code = tscSetTableFullName(pTableMetaInfo, &sToken, pSql)) != TSDB_CODE_SUCCESS) {
      goto _error_clean;
    }
@@ -1205,9 +1208,8 @@ int doParseInsertSql(SSqlObj *pSql, char *str) {
        str += index;
        if (TK_STRING == sToken.type) {
-          sToken.n = strdequote(sToken.z);
+          strdequote(sToken.z);
-          strtrim(sToken.z);
+          sToken.n = strtrim(sToken.z);
-          sToken.n = (uint32_t)strlen(sToken.z);
        }
        if (sToken.type == TK_RP) {

--- a/src/client/src/tscPrepare.c
+++ b/src/client/src/tscPrepare.c
@@ -494,7 +494,7 @@ TAOS_STMT* taos_stmt_init(TAOS* taos) {
  tsem_init(&pSql->rspSem, 0, 0);
  pSql->signature     = pSql;
  pSql->pTscObj       = pObj;
-  pSql->pTscObj->pSql = pSql;
+  //pSql->pTscObj->pSql = pSql;
  pSql->maxRetry      = TSDB_MAX_REPLICA_NUM;
  pStmt->pSql = pSql;
@@ -515,7 +515,7 @@ int taos_stmt_prepare(TAOS_STMT* stmt, const char* sql, unsigned long length) {
  //doAsyncQuery(pObj, pSql, waitForQueryRsp, taos, sqlstr, sqlLen);
  SSqlCmd *pCmd    = &pSql->cmd;
  SSqlRes *pRes    = &pSql->res;
-  pSql->param      = (void*)pStmt->taos;
+  pSql->param      = (void*)pSql;
  pSql->fp         = waitForQueryRsp;
  pSql->insertType = TSDB_QUERY_TYPE_STMT_INSERT;
@@ -613,7 +613,12 @@ int taos_stmt_execute(TAOS_STMT* stmt) {
    } else {
      tfree(pStmt->pSql->sqlstr);
      pStmt->pSql->sqlstr = sql;
-      ret = taos_query(pStmt->taos, pStmt->pSql->sqlstr);
+      SSqlObj* pSql = taos_query((TAOS*)pStmt->taos, pStmt->pSql->sqlstr);
+      if (pSql != NULL) {
+        ret = pSql->res.code;
+      } else {
+        ret = terrno;
+      } 
    }
  }
  return ret;

--- a/src/client/src/tscProfile.c
+++ b/src/client/src/tscProfile.c
@@ -88,13 +88,23 @@ void tscSaveSlowQueryFp(void *handle, void *tmrId) {
 }
 void tscSaveSlowQuery(SSqlObj *pSql) {
-  const static int64_t SLOW_QUERY_INTERVAL = 3000000L;
+  const static int64_t SLOW_QUERY_INTERVAL = 3000000L; // todo configurable
-  if (pSql->res.useconds < SLOW_QUERY_INTERVAL) return;
+  size_t size = 200;  // other part of sql string, expect the main sql str
+  if (pSql->res.useconds < SLOW_QUERY_INTERVAL) {
+    return;
+  }
  tscTrace("%p query time:%" PRId64 " sql:%s", pSql, pSql->res.useconds, pSql->sqlstr);
+  int32_t sqlSize = TSDB_SHOW_SQL_LEN + size;
-  char *sql = malloc(200);
-  int   len = snprintf(sql, 200, "insert into %s.slowquery values(now, '%s', %" PRId64 ", %" PRId64 ", '", tsMonitorDbName,
+  char *sql = malloc(sqlSize);
+  if (sql == NULL) {
+    tscError("%p failed to allocate memory to sent slow query to dnode", pSql);
+    return;
+  }
+  int len = snprintf(sql, size, "insert into %s.slowquery values(now, '%s', %" PRId64 ", %" PRId64 ", '", tsMonitorDbName,
          pSql->pTscObj->user, pSql->stime, pSql->res.useconds);
  int sqlLen = snprintf(sql + len, TSDB_SHOW_SQL_LEN, "%s", pSql->sqlstr);
  if (sqlLen > TSDB_SHOW_SQL_LEN - 1) {
@@ -102,8 +112,8 @@ void tscSaveSlowQuery(SSqlObj *pSql) {
  } else {
    sqlLen += len;
  }
  strcpy(sql + sqlLen, "')");
  taosTmrStart(tscSaveSlowQueryFp, 200, sql, tscTmr);
 }

--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -163,8 +163,7 @@ static int32_t handlePassword(SSqlCmd* pCmd, SSQLToken* pPwd) {
  }
  strdequote(pPwd->z);
-  strtrim(pPwd->z);  // trim space before and after passwords
+  pPwd->n = strtrim(pPwd->z);  // trim space before and after passwords
-  pPwd->n = strlen(pPwd->z);
  if (pPwd->n <= 0) {
    return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
@@ -226,7 +225,7 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
      } else if (pInfo->type == TSDB_SQL_DROP_TABLE) {
        assert(pInfo->pDCLInfo->nTokens == 1);
-        if (tscSetTableId(pTableMetaInfo, pzName, pSql) != TSDB_CODE_SUCCESS) {
+        if (tscSetTableFullName(pTableMetaInfo, pzName, pSql) != TSDB_CODE_SUCCESS) {
          return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg3);
        }
      } else if (pInfo->type == TSDB_SQL_DROP_DNODE) {
@@ -353,7 +352,7 @@ int32_t tscToSQLCmd(SSqlObj* pSql, struct SSqlInfo* pInfo) {
        return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg2);
      }
-      if (tscSetTableId(pTableMetaInfo, pToken, pSql) != TSDB_CODE_SUCCESS) {
+      if (tscSetTableFullName(pTableMetaInfo, pToken, pSql) != TSDB_CODE_SUCCESS) {
        return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg2);
      }
@@ -686,7 +685,7 @@ int32_t parseSlidingClause(SQueryInfo* pQueryInfo, SQuerySQL* pQuerySql) {
  return TSDB_CODE_SUCCESS;
 }
-int32_t tscSetTableId(STableMetaInfo* pTableMetaInfo, SSQLToken* pzTableName, SSqlObj* pSql) {
+int32_t tscSetTableFullName(STableMetaInfo* pTableMetaInfo, SSQLToken* pzTableName, SSqlObj* pSql) {
  const char* msg = "name too long";
  SSqlCmd* pCmd = &pSql->cmd;
@@ -1465,7 +1464,6 @@ static int32_t setExprInfoForFunctions(SQueryInfo* pQueryInfo, SSchema* pSchema,
 int32_t addExprAndResultField(SQueryInfo* pQueryInfo, int32_t colIndex, tSQLExprItem* pItem, bool finalResult) {
  STableMetaInfo* pTableMetaInfo = NULL;
  int32_t optr = pItem->pNode->nSQLOptr;
  const char* msg1 = "not support column types";
@@ -4294,7 +4292,7 @@ int32_t setAlterTableInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
    return invalidSqlErrMsg(pQueryInfo->msg, msg1);
  }
-  if (tscSetTableId(pTableMetaInfo, &(pAlterSQL->name), pSql) != TSDB_CODE_SUCCESS) {
+  if (tscSetTableFullName(pTableMetaInfo, &(pAlterSQL->name), pSql) != TSDB_CODE_SUCCESS) {
    return invalidSqlErrMsg(pQueryInfo->msg, msg2);
  }
@@ -4671,8 +4669,7 @@ int32_t validateColumnName(char* name) {
  if (token.type == TK_STRING) {
    strdequote(token.z);
-    strtrim(token.z);
+    token.n = strtrim(token.z);
-    token.n = (uint32_t)strlen(token.z);
    int32_t k = tSQLGetToken(token.z, &token.type);
    if (k != token.n) {
@@ -5516,7 +5513,7 @@ int32_t doCheckForCreateTable(SSqlObj* pSql, int32_t subClauseIndex, SSqlInfo* p
    return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
  }
-  if (tscSetTableId(pTableMetaInfo, pzTableName, pSql) != TSDB_CODE_SUCCESS) {
+  if (tscSetTableFullName(pTableMetaInfo, pzTableName, pSql) != TSDB_CODE_SUCCESS) {
    return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg2);
  }
@@ -5571,7 +5568,7 @@ int32_t doCheckForCreateFromStable(SSqlObj* pSql, SSqlInfo* pInfo) {
    return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
  }
-  if (tscSetTableId(pStableMeterMetaInfo, pToken, pSql) != TSDB_CODE_SUCCESS) {
+  if (tscSetTableFullName(pStableMeterMetaInfo, pToken, pSql) != TSDB_CODE_SUCCESS) {
    return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
  }
@@ -5617,7 +5614,7 @@ int32_t doCheckForCreateFromStable(SSqlObj* pSql, SSqlInfo* pInfo) {
  }
  STableMetaInfo* pTableMeterMetaInfo = tscGetMetaInfo(pQueryInfo, TABLE_INDEX);
-  ret = tscSetTableId(pTableMeterMetaInfo, &pInfo->pCreateTableInfo->name, pSql);
+  ret = tscSetTableFullName(pTableMeterMetaInfo, &pInfo->pCreateTableInfo->name, pSql);
  if (ret != TSDB_CODE_SUCCESS) {
    return ret;
  }
@@ -5660,7 +5657,7 @@ int32_t doCheckForStream(SSqlObj* pSql, SSqlInfo* pInfo) {
    return invalidSqlErrMsg(pQueryInfo->msg, msg1);
  }
-  if (tscSetTableId(pTableMetaInfo, &srcToken, pSql) != TSDB_CODE_SUCCESS) {
+  if (tscSetTableFullName(pTableMetaInfo, &srcToken, pSql) != TSDB_CODE_SUCCESS) {
    return invalidSqlErrMsg(pQueryInfo->msg, msg2);
  }
@@ -5691,7 +5688,7 @@ int32_t doCheckForStream(SSqlObj* pSql, SSqlInfo* pInfo) {
  }
  // set the created table[stream] name
-  if (tscSetTableId(pTableMetaInfo, pzTableName, pSql) != TSDB_CODE_SUCCESS) {
+  if (tscSetTableFullName(pTableMetaInfo, pzTableName, pSql) != TSDB_CODE_SUCCESS) {
    return invalidSqlErrMsg(pQueryInfo->msg, msg1);
  }
@@ -5800,7 +5797,7 @@ int32_t doCheckForQuery(SSqlObj* pSql, SQuerySQL* pQuerySql, int32_t index) {
    STableMetaInfo* pMeterInfo1 = tscGetMetaInfo(pQueryInfo, i);
    SSQLToken t = {.type = TSDB_DATA_TYPE_BINARY, .n = pTableItem->nLen, .z = pTableItem->pz};
-    if (tscSetTableId(pMeterInfo1, &t, pSql) != TSDB_CODE_SUCCESS) {
+    if (tscSetTableFullName(pMeterInfo1, &t, pSql) != TSDB_CODE_SUCCESS) {
      return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg1);
    }

--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -220,9 +220,7 @@ void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcIpSet *pIpSet) {
  if (pObj->signature != pObj) {
    tscTrace("%p sql is already released or DB connection is closed, freed:%d pObj:%p signature:%p", pSql, pSql->freed,
             pObj, pObj->signature);
-    if (pSql != pObj->pSql) {
+    tscFreeSqlObj(pSql);
-      tscFreeSqlObj(pSql);
-    }
    rpcFreeCont(rpcMsg->pCont);
    return;
  }
@@ -257,6 +255,9 @@ void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcIpSet *pIpSet) {
        rpcMsg->code = TSDB_CODE_NOT_READY;
        rpcFreeCont(rpcMsg->pCont);
        return;
+      } else if (pCmd->command == TSDB_SQL_META) {
+//        rpcFreeCont(rpcMsg->pCont);
+//        return;
      } else {
        tscWarn("%p it shall renew table meta, code:%s, retry:%d", pSql, tstrerror(rpcMsg->code), ++pSql->retry);
@@ -331,21 +332,11 @@ void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcIpSet *pIpSet) {
    rpcMsg->code = (*tscProcessMsgRsp[pCmd->command])(pSql);
  if (rpcMsg->code != TSDB_CODE_ACTION_IN_PROGRESS) {
-    void *taosres = tscKeepConn[pCmd->command] ? pSql : NULL;
    rpcMsg->code = pRes->code ? pRes->code : pRes->numOfRows;
    tscTrace("%p SQL result:%s res:%p", pSql, tstrerror(pRes->code), pSql);
-    /*
-     * Whether to free sqlObj or not should be decided before call the user defined function, since this SqlObj
-     * may be freed in UDF, and reused by other threads before tscShouldBeFreed called, in which case
-     * tscShouldBeFreed checks an object which is actually allocated by other threads.
-     *
-     * If this block of memory is re-allocated for an insert thread, in which tscKeepConn[command] equals to 0,
-     * the tscShouldBeFreed will success and tscFreeSqlObj free it immediately.
-     */
    bool shouldFree = tscShouldBeFreed(pSql);
-    (*pSql->fp)(pSql->param, taosres, rpcMsg->code);
+    (*pSql->fp)(pSql->param, pSql, rpcMsg->code);
    if (shouldFree) {
      tscTrace("%p sqlObj is automatically freed", pSql);

--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -52,7 +52,7 @@ static bool validPassword(const char* passwd) {
  return validImpl(passwd, TSDB_PASSWORD_LEN);
 }
-STscObj *taosConnectImpl(const char *ip, const char *user, const char *pass, const char *db, uint16_t port,
+SSqlObj *taosConnectImpl(const char *ip, const char *user, const char *pass, const char *db, uint16_t port,
                       void (*fp)(void *, TAOS_RES *, int), void *param, void **taos) {
  taos_init();
@@ -120,10 +120,8 @@ STscObj *taosConnectImpl(const char *ip, const char *user, const char *pass, con
  pSql->pTscObj = pObj;
  pSql->signature = pSql;
  pSql->maxRetry = TSDB_MAX_REPLICA_NUM;
  tsem_init(&pSql->rspSem, 0, 0);
-  pObj->pSql = pSql;
  pObj->pDnodeConn = pDnodeConn;
  pSql->fp = fp;
@@ -143,42 +141,38 @@ STscObj *taosConnectImpl(const char *ip, const char *user, const char *pass, con
  // tsRpcHeaderSize will be updated during RPC initialization, so only after it initialization, this value is valid
  tsInsertHeadSize = tsRpcHeadSize + sizeof(SMsgDesc) + sizeof(SSubmitMsg);
-  return pObj;
+  return pSql;
 }
 static void syncConnCallback(void *param, TAOS_RES *tres, int code) {
-  STscObj *pObj = (STscObj *)param;
+  SSqlObj *pSql = (SSqlObj *) tres;
-  assert(pObj != NULL && pObj->pSql != NULL);
+  assert(pSql != NULL);
-  if (code < 0) {
-    pObj->pSql->res.code = code;
-  }
-  sem_post(&pObj->pSql->rspSem);
+  sem_post(&pSql->rspSem);
 }
 TAOS *taos_connect(const char *ip, const char *user, const char *pass, const char *db, uint16_t port) {
  tscTrace("try to create a connection to %s:%u, user:%s db:%s", ip, port, user, db);
-  STscObj *pObj = taosConnectImpl(ip, user, pass, db, port, NULL, NULL, NULL);
+  STscObj* pObj = NULL;
-  if (pObj != NULL) {
+  SSqlObj *pSql = taosConnectImpl(ip, user, pass, db, port, syncConnCallback, NULL, (void**) &pObj);
-    SSqlObj* pSql = pObj->pSql;
+  if (pSql != NULL) {
-    assert(pSql != NULL);
    pSql->fp = syncConnCallback;
-    pSql->param = pObj;
+    pSql->param = pSql;
    tscProcessSql(pSql);
    sem_wait(&pSql->rspSem);
    if (pSql->res.code != TSDB_CODE_SUCCESS) {
      terrno = pSql->res.code;
+      taos_free_result(pSql);
      taos_close(pObj);
      return NULL;
    }
    tscTrace("%p DB connection is opening, dnodeConn:%p", pObj, pObj->pDnodeConn);
+    taos_free_result(pSql);
    // version compare only requires the first 3 segments of the version string
    int code = taosCheckVersion(version, taos_get_server_info(pObj), 3);
    if (code != 0) {
@@ -195,17 +189,14 @@ TAOS *taos_connect(const char *ip, const char *user, const char *pass, const cha
 TAOS *taos_connect_a(char *ip, char *user, char *pass, char *db, uint16_t port, void (*fp)(void *, TAOS_RES *, int),
                     void *param, void **taos) {
-  STscObj* pObj = taosConnectImpl(ip, user, pass, db, port, fp, param, taos);
+  SSqlObj* pSql = taosConnectImpl(ip, user, pass, db, port, fp, param, taos);
-  if (pObj == NULL) {
+  if (pSql == NULL) {
    return NULL;
  }
-  SSqlObj* pSql = pObj->pSql;
  pSql->res.code = tscProcessSql(pSql);
-  tscTrace("%p DB async connection is opening", pObj);
+  tscTrace("%p DB async connection is opening", taos);
+  return taos;
-  return pObj;
 }
 void taos_close(TAOS *taos) {
@@ -265,41 +256,40 @@ int taos_query_imp(STscObj *pObj, SSqlObj *pSql) {
 }
 void waitForQueryRsp(void *param, TAOS_RES *tres, int code) {
-  assert(param != NULL);
+  assert(tres != NULL);
-  SSqlObj *pSql = ((STscObj *)param)->pSql;
-  // valid error code is less than 0
-  if (code < 0) {
-    pSql->res.code = code;
-  }
+  SSqlObj *pSql = (SSqlObj *) tres;
  sem_post(&pSql->rspSem);
 }
-int taos_query(TAOS *taos, const char *sqlstr) {
+TAOS_RES* taos_query(TAOS *taos, const char *sqlstr) {
  STscObj *pObj = (STscObj *)taos;
  if (pObj == NULL || pObj->signature != pObj) {
    terrno = TSDB_CODE_DISCONNECTED;
-    return TSDB_CODE_DISCONNECTED;
+    return NULL;
+  }
+  int32_t sqlLen = strlen(sqlstr);
+  if (sqlLen > tsMaxSQLStringLen) {
+    tscError("sql string exceeds max length:%d", tsMaxSQLStringLen);
+    terrno = TSDB_CODE_INVALID_SQL;
+    return NULL;
+  }
+  taosNotePrintTsc(sqlstr);
+  SSqlObj* pSql = calloc(1, sizeof(SSqlObj));
+  if (pSql == NULL) {
+    tscError("failed to malloc sqlObj");
+    terrno = TSDB_CODE_CLI_OUT_OF_MEMORY;
+    return NULL;
  }
-  SSqlObj* pSql = pObj->pSql;
-  size_t   sqlLen = strlen(sqlstr);
  doAsyncQuery(pObj, pSql, waitForQueryRsp, taos, sqlstr, sqlLen);
  // wait for the callback function to post the semaphore
  tsem_wait(&pSql->rspSem);
-  return pSql->res.code;
+  return pSql;
-}
-TAOS_RES *taos_use_result(TAOS *taos) {
-  STscObj *pObj = (STscObj *)taos;
-  if (pObj == NULL || pObj->signature != pObj) {
-    terrno = TSDB_CODE_DISCONNECTED;
-    return NULL;
-  }
-  return pObj->pSql;
 }
 int taos_result_precision(TAOS_RES *res) {
@@ -332,18 +322,18 @@ int taos_num_fields(TAOS_RES *res) {
  return num;
 }
-int taos_field_count(TAOS *taos) {
+int taos_field_count(TAOS_RES *tres) {
-  STscObj *pObj = (STscObj *)taos;
+  SSqlObj* pSql = (SSqlObj*) tres;
-  if (pObj == NULL || pObj->signature != pObj) return 0;
+  if (pSql == NULL || pSql->signature != pSql) return 0;
-  return taos_num_fields(pObj->pSql);
+  return taos_num_fields(pSql);
 }
-int taos_affected_rows(TAOS *taos) {
+int taos_affected_rows(TAOS_RES *tres) {
-  STscObj *pObj = (STscObj *)taos;
+  SSqlObj* pSql = (SSqlObj*) tres;
-  if (pObj == NULL || pObj->signature != pObj) return 0;
+  if (pSql == NULL || pSql->signature != pSql) return 0;
-  return (pObj->pSql->res.numOfRows);
+  return (pSql->res.numOfRows);
 }
 TAOS_FIELD *taos_fetch_fields(TAOS_RES *res) {
@@ -385,9 +375,8 @@ int taos_fetch_block_impl(TAOS_RES *res, TAOS_ROW *rows) {
  SSqlObj *pSql = (SSqlObj *)res;
  SSqlCmd *pCmd = &pSql->cmd;
  SSqlRes *pRes = &pSql->res;
-  STscObj *pObj = pSql->pTscObj;
-  if (pRes->qhandle == 0 || pObj->pSql != pSql) {
+  if (pRes->qhandle == 0 || pSql->signature != pSql) {
    *rows = NULL;
    return 0;
  }
@@ -521,95 +510,76 @@ int taos_select_db(TAOS *taos, const char *db) {
  }
  snprintf(sql, tListLen(sql), "use %s", db);
-  return taos_query(taos, sql);
+  SSqlObj* pSql = taos_query(taos, sql);
+  int32_t code = pSql->res.code;
+  taos_free_result(pSql);
+  return code;
 }
 void taos_free_result(TAOS_RES *res) {
-  if (res == NULL) return;
  SSqlObj *pSql = (SSqlObj *)res;
+  tscTrace("%p start to free result", res);
+  if (pSql == NULL || pSql->signature != pSql) {
+    tscTrace("%p result has been freed", pSql);
+    return;
+  }
  SSqlRes *pRes = &pSql->res;
  SSqlCmd *pCmd = &pSql->cmd;
-  tscTrace("%p start to free result", pSql);
+  // The semaphore can not be changed while freeing async sub query objects.
-  if (pSql->signature != pSql) return;
-  STscObj* pObj = pSql->pTscObj;
  if (pRes == NULL || pRes->qhandle == 0) {
-    /* Query rsp is not received from vnode, so the qhandle is NULL */
+    tscTrace("%p SqlObj is freed by app, qhandle is null", pSql);
-    tscTrace("%p qhandle is null, abort free, fp:%p", pSql, pSql->fp);
+    tscFreeSqlObj(pSql);
-    // The semaphore can not be changed while freeing async sub query objects.
-    if (pObj->pSql != pSql) {
-      tscTrace("%p SqlObj is freed by app", pSql);
-      tscFreeSqlObj(pSql);
-    } else {
-      tscPartiallyFreeSqlObj(pSql);
-    }
    return;
  }
  // set freeFlag to 1 in retrieve message if there are un-retrieved results data in node
  SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(&pSql->cmd, 0);
  if (pQueryInfo == NULL) {
-    tscPartiallyFreeSqlObj(pSql);
+    tscFreeSqlObj(pSql);
    return;
  }
  pQueryInfo->type = TSDB_QUERY_TYPE_FREE_RESOURCE;
-  STscObj* pTscObj = pSql->pTscObj;
  STableMetaInfo *pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
  /*
-   * case 1. Partial data have been retrieved from vnodes, but not all data has been retrieved yet.
+   * If the query process is cancelled by user in stable query, tscProcessSql should not be called
-   *         We need to recycle the connection by noticing the vnode return 0 results.
+   * for each subquery. Because the failure of execution tsProcessSql may trigger the callback function
-   * case 2. When the query response is received from vnodes and the numOfRows is set to 0, the user calls
+   * be executed, and the retry efforts may result in double free the resources, e.g.,SRetrieveSupport
-   *         taos_free_result before the taos_fetch_row is called in non-stream computing,
-   *         we need to recycle the connection.
-   * case 3. If the query process is cancelled by user in stable query, tscProcessSql should not be called
-   *         for each subquery. Because the failure of execution tsProcessSql may trigger the callback function
-   *         be executed, and the retry efforts may result in double free the resources, e.g.,SRetrieveSupport
   */
-  if ((pCmd->command == TSDB_SQL_SELECT ||
+  if (pRes->code == TSDB_CODE_SUCCESS && pRes->completed == false &&
-       pCmd->command == TSDB_SQL_SHOW ||
+      (pCmd->command == TSDB_SQL_SELECT || pCmd->command == TSDB_SQL_SHOW ||
-       pCmd->command == TSDB_SQL_RETRIEVE ||
+       pCmd->command == TSDB_SQL_RETRIEVE || pCmd->command == TSDB_SQL_FETCH) &&
-       pCmd->command == TSDB_SQL_FETCH) && pRes->code == TSDB_CODE_SUCCESS && pRes->completed == false &&
       (pCmd->command == TSDB_SQL_SELECT && pSql->pStream == NULL && pTableMetaInfo->pTableMeta != NULL)) {
    pCmd->command = (pCmd->command > TSDB_SQL_MGMT) ? TSDB_SQL_RETRIEVE : TSDB_SQL_FETCH;
-    tscTrace("%p send msg to free qhandle in vnode, code:%d, numOfRows:%d, command:%s", pSql, pRes->code, pRes->numOfRows,
+    tscTrace("%p start to send msg to free qhandle in dnode, command:%s", pSql, sqlCmd[pCmd->command]);
-        sqlCmd[pCmd->command]);
    pSql->freed = 1;
    tscProcessSql(pSql);
-    // waits for response and then goes on
+    // in case of sync model query, waits for response and then goes on
-    if (pTscObj->pSql == pSql) {
+    if (pSql->fp == waitForQueryRsp || pSql->fp == waitForRetrieveRsp) {
      sem_wait(&pSql->rspSem);
    }
-  } else { // if no free resource msg is sent to vnode, we free this object immediately.
-    if (pTscObj->pSql != pSql) {
-      tscFreeSqlObj(pSql);
-      tscTrace("%p sql result is freed by app", pSql);
-    } else {
-      tscPartiallyFreeSqlObj(pSql);
-      tscTrace("%p sql result is freed by app", pSql);
-    }
  }
+  tscFreeSqlObj(pSql);
+  tscTrace("%p sql result is freed by app", pSql);
 }
 // todo should not be used in async query
-int taos_errno(TAOS *taos) {
+int taos_errno(TAOS_RES *tres) {
-  STscObj *pObj = (STscObj *)taos;
+  SSqlObj *pSql = (SSqlObj *) tres;
-  if (pObj == NULL || pObj->signature != pObj) {
+  if (pSql == NULL || pSql->signature != pSql) {
    return terrno;
  }
-  return pObj->pSql->res.code;
+  return pSql->res.code;
 }
 /*
@@ -632,14 +602,13 @@ static bool hasAdditionalErrorInfo(int32_t code, SSqlCmd *pCmd) {
 }
 // todo should not be used in async model
-char *taos_errstr(TAOS *taos) {
+char *taos_errstr(TAOS_RES *tres) {
-  STscObj *pObj = (STscObj *)taos;
+  SSqlObj *pSql = (SSqlObj *) tres;
-  if (pObj == NULL || pObj->signature != pObj)
+  if (pSql == NULL || pSql->signature != pSql) {
-    return (char*)tstrerror(terrno);
+    return (char*) tstrerror(terrno);
+  }
-  SSqlObj* pSql = pObj->pSql;
  if (hasAdditionalErrorInfo(pSql->res.code, &pSql->cmd)) {
    return pSql->cmd.payload;
  } else {
@@ -769,7 +738,8 @@ int taos_validate_sql(TAOS *taos, const char *sql) {
    return TSDB_CODE_DISCONNECTED;
  }
-  SSqlObj *pSql = pObj->pSql;
+  SSqlObj* pSql = calloc(1, sizeof(SSqlObj));
  SSqlRes *pRes = &pSql->res;
  SSqlCmd *pCmd = &pSql->cmd;
@@ -847,9 +817,7 @@ static int tscParseTblNameList(SSqlObj *pSql, const char *tblNameList, int32_t t
    tblName[len] = '\0';
    str = nextStr + 1;
+    len = strtrim(tblName);
-    strtrim(tblName);
-    len = (uint32_t)strlen(tblName);
    SSQLToken sToken = {.n = len, .type = TK_ID, .z = tblName};
    tSQLGetToken(tblName, &sToken.type);
@@ -861,7 +829,7 @@ static int tscParseTblNameList(SSqlObj *pSql, const char *tblNameList, int32_t t
      return code;
    }
-    if ((code = tscSetTableId(pTableMetaInfo, &sToken, pSql)) != TSDB_CODE_SUCCESS) {
+    if ((code = tscSetTableFullName(pTableMetaInfo, &sToken, pSql)) != TSDB_CODE_SUCCESS) {
      return code;
    }
@@ -902,7 +870,7 @@ int taos_load_table_info(TAOS *taos, const char *tableNameList) {
    return TSDB_CODE_DISCONNECTED;
  }
-  SSqlObj *pSql = pObj->pSql;
+  SSqlObj* pSql = calloc(1, sizeof(SSqlObj));
  SSqlRes *pRes = &pSql->res;
  pRes->numOfTotal = 0;  // the number of getting table meta from server

--- a/src/client/src/tscStream.c
+++ b/src/client/src/tscStream.c
@@ -459,14 +459,14 @@ static int64_t tscGetLaunchTimestamp(const SSqlStream *pStream) {
  return (pStream->precision == TSDB_TIME_PRECISION_MICRO) ? timer / 1000L : timer;
 }
-static void setErrorInfo(STscObj* pObj, int32_t code, char* info) {
+static void setErrorInfo(SSqlObj* pSql, int32_t code, char* info) {
-  if (pObj == NULL) {
+  if (pSql == NULL) {
    return;
  }
-  SSqlCmd* pCmd = &pObj->pSql->cmd;
+  SSqlCmd* pCmd = &pSql->cmd;
-  pObj->pSql->res.code = code;
+  pSql->res.code = code;
  if (info != NULL) {
    strncpy(pCmd->payload, info, pCmd->payloadLen);
@@ -480,7 +480,7 @@ TAOS_STREAM *taos_open_stream(TAOS *taos, const char *sqlstr, void (*fp)(void *p
  SSqlObj *pSql = (SSqlObj *)calloc(1, sizeof(SSqlObj));
  if (pSql == NULL) {
-    setErrorInfo(pObj, TSDB_CODE_CLI_OUT_OF_MEMORY, NULL);
+    setErrorInfo(pSql, TSDB_CODE_CLI_OUT_OF_MEMORY, NULL);
    return NULL;
  }
@@ -490,14 +490,14 @@ TAOS_STREAM *taos_open_stream(TAOS *taos, const char *sqlstr, void (*fp)(void *p
  SSqlRes *pRes = &pSql->res;
  int ret = tscAllocPayload(pCmd, TSDB_DEFAULT_PAYLOAD_SIZE);
  if (TSDB_CODE_SUCCESS != ret) {
-    setErrorInfo(pObj, ret, NULL);
+    setErrorInfo(pSql, ret, NULL);
    free(pSql);
    return NULL;
  }
  pSql->sqlstr = strdup(sqlstr);
  if (pSql->sqlstr == NULL) {
-    setErrorInfo(pObj, TSDB_CODE_CLI_OUT_OF_MEMORY, NULL);
+    setErrorInfo(pSql, TSDB_CODE_CLI_OUT_OF_MEMORY, NULL);
    tfree(pSql);
    return NULL;
@@ -511,7 +511,7 @@ TAOS_STREAM *taos_open_stream(TAOS *taos, const char *sqlstr, void (*fp)(void *p
  tscResetSqlCmdObj(&pSql->cmd);
  ret = tscAllocPayload(&pSql->cmd, TSDB_DEFAULT_PAYLOAD_SIZE);
  if (TSDB_CODE_SUCCESS != ret) {
-    setErrorInfo(pObj, ret, NULL);
+    setErrorInfo(pSql, ret, NULL);
    tscError("%p open stream failed, sql:%s, code:%d", pSql, sqlstr, TSDB_CODE_CLI_OUT_OF_MEMORY);
    tscFreeSqlObj(pSql);
    return NULL;
@@ -521,7 +521,7 @@ TAOS_STREAM *taos_open_stream(TAOS *taos, const char *sqlstr, void (*fp)(void *p
  SQLInfoDestroy(&SQLInfo);
  if (pRes->code != TSDB_CODE_SUCCESS) {
-    setErrorInfo(pObj, pRes->code, pCmd->payload);
+    setErrorInfo(pSql, pRes->code, pCmd->payload);
    tscError("%p open stream failed, sql:%s, reason:%s, code:%d", pSql, sqlstr, pCmd->payload, pRes->code);
    tscFreeSqlObj(pSql);
@@ -530,7 +530,7 @@ TAOS_STREAM *taos_open_stream(TAOS *taos, const char *sqlstr, void (*fp)(void *p
  SSqlStream *pStream = (SSqlStream *)calloc(1, sizeof(SSqlStream));
  if (pStream == NULL) {
-    setErrorInfo(pObj, TSDB_CODE_CLI_OUT_OF_MEMORY, NULL);
+    setErrorInfo(pSql, TSDB_CODE_CLI_OUT_OF_MEMORY, NULL);
    tscError("%p open stream failed, sql:%s, reason:%s, code:%d", pSql, sqlstr, pCmd->payload, pRes->code);
    tscFreeSqlObj(pSql);

--- a/src/client/src/tscSub.c
+++ b/src/client/src/tscSub.c
@@ -181,21 +181,23 @@ static SArray* getTableList( SSqlObj* pSql ) {
  const char* p = strstr( pSql->sqlstr, " from " );
  char* sql = alloca(strlen(p) + 32);
  sprintf(sql, "select tbid(tbname)%s", p);
-  int code = taos_query( pSql->pTscObj, sql );
-  if (code != TSDB_CODE_SUCCESS) {
+  SSqlObj* pSql1 = taos_query(pSql->pTscObj, sql);
-    tscError("failed to retrieve table id: %s", tstrerror(code));
+  if (terrno != TSDB_CODE_SUCCESS) {
+    tscError("failed to retrieve table id: %s", tstrerror(terrno));
    return NULL;
  }
-  TAOS_RES* res = taos_use_result( pSql->pTscObj );
  TAOS_ROW row;
  SArray* result = taosArrayInit( 128, sizeof(STidTags) );
-  while ((row = taos_fetch_row(res))) {
+  while ((row = taos_fetch_row(pSql1))) {
    STidTags tags;
    memcpy(&tags, row[0], sizeof(tags));
    taosArrayPush(result, &tags);
  }
+  taos_free_result(pSql1);
  return result;
 }

--- a/src/client/src/tscSubquery.c
+++ b/src/client/src/tscSubquery.c
@@ -1715,6 +1715,7 @@ static void multiVnodeInsertMerge(void* param, TAOS_RES* tres, int numOfRows) {
    pParentObj->res.numOfRows += numOfRows;
  }
+  taos_free_result(tres);
  int32_t completed = atomic_add_fetch_32(&pState->numOfCompleted, 1);
  if (completed < total) {
    return;
@@ -1732,7 +1733,7 @@ static void multiVnodeInsertMerge(void* param, TAOS_RES* tres, int numOfRows) {
  pParentObj->fp = pParentObj->fetchFp;
  // all data has been sent to vnode, call user function
-  (*pParentObj->fp)(pParentObj->param, tres, numOfRows);
+  (*pParentObj->fp)(pParentObj->param, pParentObj, numOfRows);
 }
 int32_t tscHandleMultivnodeInsert(SSqlObj *pSql) {

--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -409,8 +409,10 @@ void tscPartiallyFreeSqlObj(SSqlObj* pSql) {
 }
 void tscFreeSqlObj(SSqlObj* pSql) {
-  if (pSql == NULL || pSql->signature != pSql) return;
+  if (pSql == NULL || pSql->signature != pSql) {
+    return;
+  }
  tscTrace("%p start to free sql object", pSql);
  tscPartiallyFreeSqlObj(pSql);
@@ -424,6 +426,7 @@ void tscFreeSqlObj(SSqlObj* pSql) {
  pCmd->allocSize = 0;
  tfree(pSql->sqlstr);
+  sem_destroy(&pSql->rspSem);
  free(pSql);
 }
@@ -750,16 +753,7 @@ void tscCloseTscObj(STscObj* pObj) {
  assert(pObj != NULL);
  pObj->signature = NULL;
-  SSqlObj* pSql = pObj->pSql;
-  if (pSql) {
-    terrno = pSql->res.code;
-    sem_destroy(&pSql->rspSem);
-  }
  taosTmrStopA(&(pObj->pTimer));
-  tscFreeSqlObj(pSql);
  pthread_mutex_destroy(&pObj->mutex);
  if (pObj->pDnodeConn != NULL) {
@@ -1238,9 +1232,8 @@ void tscColumnListDestroy(SArray* pColumnList) {
 *
 */
 static int32_t validateQuoteToken(SSQLToken* pToken) {
-  pToken->n = strdequote(pToken->z);
+  strdequote(pToken->z);
-  strtrim(pToken->z);
+  pToken->n = strtrim(pToken->z);
-  pToken->n = (uint32_t)strlen(pToken->z);
  int32_t k = tSQLGetToken(pToken->z, &pToken->type);
@@ -1262,9 +1255,8 @@ int32_t tscValidateName(SSQLToken* pToken) {
  char* sep = strnchr(pToken->z, TS_PATH_DELIMITER[0], pToken->n, true);
  if (sep == NULL) {  // single part
    if (pToken->type == TK_STRING) {
-      pToken->n = strdequote(pToken->z);
+      strdequote(pToken->z);
-      strtrim(pToken->z);
+      pToken->n = strtrim(pToken->z);
-      pToken->n = (uint32_t)strlen(pToken->z);
      int len = tSQLGetToken(pToken->z, &pToken->type);
@@ -1289,8 +1281,7 @@ int32_t tscValidateName(SSQLToken* pToken) {
    char*   pStr = pToken->z;
    if (pToken->type == TK_SPACE) {
-      strtrim(pToken->z);
+      pToken->n = strtrim(pToken->z);
-      pToken->n = (uint32_t)strlen(pToken->z);
    }
    pToken->n = tSQLGetToken(pToken->z, &pToken->type);
@@ -1471,22 +1462,24 @@ bool tscShouldFreeHeatBeat(SSqlObj* pHb) {
 * If connection need to be recycled, the SqlObj also should be freed.
 */
 bool tscShouldBeFreed(SSqlObj* pSql) {
-  if (pSql == NULL || pSql->signature != pSql || pSql->fp == NULL) {
+  if (pSql == NULL || pSql->signature != pSql) {
    return false;
  }
+  assert(pSql->fp != NULL);
  STscObj* pTscObj = pSql->pTscObj;
-  if (pSql->pStream != NULL || pTscObj->pHb == pSql || pTscObj->pSql == pSql || pSql->pSubscription != NULL) {
+  if (pSql->pStream != NULL || pTscObj->pHb == pSql || pSql->pSubscription != NULL) {
    return false;
  }
+  // only the table meta and super table vgroup query will free resource automatically
  int32_t command = pSql->cmd.command;
-  if (command == TSDB_SQL_CONNECT || command == TSDB_SQL_INSERT) {
+  if (command == TSDB_SQL_META || command == TSDB_SQL_STABLEVGROUP) {
    return true;
-  } else {
-    return tscKeepConn[command] == 0 ||
-           (pSql->res.code != TSDB_CODE_ACTION_IN_PROGRESS && pSql->res.code != TSDB_CODE_SUCCESS);
  }
+  return false;
 }
 /**
@@ -1949,15 +1942,14 @@ int16_t tscGetJoinTagColIndexByUid(STagCond* pTagCond, uint64_t uid) {
  }
 }
-bool tscIsUpdateQuery(STscObj* pObj) {
+bool tscIsUpdateQuery(SSqlObj* pSql) {
-  if (pObj == NULL || pObj->signature != pObj) {
+  if (pSql == NULL || pSql->signature != pSql) {
    terrno = TSDB_CODE_DISCONNECTED;
    return TSDB_CODE_DISCONNECTED;
  }
-  SSqlCmd* pCmd = &pObj->pSql->cmd;
+  SSqlCmd* pCmd = &pSql->cmd;
-  return ((pCmd->command >= TSDB_SQL_INSERT && pCmd->command <= TSDB_SQL_DROP_DNODE) ||
+  return ((pCmd->command >= TSDB_SQL_INSERT && pCmd->command <= TSDB_SQL_DROP_DNODE) || TSDB_SQL_USE_DB == pCmd->command);
-          TSDB_SQL_USE_DB == pCmd->command);
 }
 int32_t tscInvalidSQLErrMsg(char* msg, const char* additionalInfo, const char* sql) {

--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/DatabaseMetaDataResultSet.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/DatabaseMetaDataResultSet.java
@@ -18,8 +18,8 @@ import java.io.InputStream;
 import java.io.Reader;
 import java.math.BigDecimal;
 import java.net.URL;
-import java.sql.*;
 import java.sql.Date;
+import java.sql.*;
 import java.util.*;
 /*
@@ -102,41 +102,49 @@ public class DatabaseMetaDataResultSet implements ResultSet {
    @Override
    public byte getByte(int columnIndex) throws SQLException {
+        columnIndex--;
        return (byte) rowCursor.getInt(columnIndex, columnMetaDataList.get(columnIndex).getColType());
    }
    @Override
    public short getShort(int columnIndex) throws SQLException {
+        columnIndex--;
        return (short) rowCursor.getInt(columnIndex, columnMetaDataList.get(columnIndex).getColType());
    }
    @Override
    public int getInt(int columnIndex) throws SQLException {
+        columnIndex--;
        return rowCursor.getInt(columnIndex, columnMetaDataList.get(columnIndex).getColType());
    }
    @Override
    public long getLong(int columnIndex) throws SQLException {
+        columnIndex--;
        return rowCursor.getLong(columnIndex, columnMetaDataList.get(columnIndex).getColType());
    }
    @Override
    public float getFloat(int columnIndex) throws SQLException {
+        columnIndex--;
        return rowCursor.getFloat(columnIndex, columnMetaDataList.get(columnIndex).getColType());
    }
    @Override
    public double getDouble(int columnIndex) throws SQLException {
+        columnIndex--;
        return rowCursor.getDouble(columnIndex, columnMetaDataList.get(columnIndex).getColType());
    }
    @Override
    public BigDecimal getBigDecimal(int columnIndex, int scale) throws SQLException {
+        columnIndex--;
        return new BigDecimal(rowCursor.getDouble(columnIndex, columnMetaDataList.get(columnIndex).getColType()));
    }
    @Override
    public byte[] getBytes(int columnIndex) throws SQLException {
+        columnIndex--;
        return (rowCursor.getString(columnIndex, columnMetaDataList.get(columnIndex).getColType())).getBytes();
    }
@@ -152,6 +160,7 @@ public class DatabaseMetaDataResultSet implements ResultSet {
    @Override
    public Timestamp getTimestamp(int columnIndex) throws SQLException {
+        columnIndex--;
        return rowCursor.getTimestamp(columnIndex);
    }

--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBConnection.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBConnection.java
@@ -84,6 +84,14 @@ public class TSDBConnection implements Connection {
 		}
 	}
+	public TSDBSubscribe createSubscribe() throws SQLException {
+		if (!this.connector.isClosed()) {
+			return new TSDBSubscribe(this.connector);
+		} else {
+			throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+		}
+	}
 	public PreparedStatement prepareStatement(String sql) throws SQLException {
 		if (!this.connector.isClosed()) {
 			return new TSDBPreparedStatement(this.connector, sql);

--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBJNIConnector.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBJNIConnector.java
@@ -99,7 +99,7 @@ public class TSDBJNIConnector {
        this.taos = this.connectImp(host, port, dbName, user, password);
        if (this.taos == TSDBConstants.JNI_NULL_POINTER) {
-            throw new SQLException(TSDBConstants.WrapErrMsg(this.getErrMsg()), "", this.getErrCode());
+            throw new SQLException(TSDBConstants.WrapErrMsg(this.getErrMsg(null)), "", this.getErrCode(null));
        }
        return true;
@@ -117,52 +117,57 @@ public class TSDBJNIConnector {
            freeResultSet(taosResultSetPointer);
        }
-        int code;
+        long pSql = 0l;
        try {
-            code = this.executeQueryImp(sql.getBytes(TaosGlobalConfig.getCharset()), this.taos);
+            pSql = this.executeQueryImp(sql.getBytes(TaosGlobalConfig.getCharset()), this.taos);
        } catch (Exception e) {
            e.printStackTrace();
+            this.freeResultSet(pSql);
            throw new SQLException(TSDBConstants.WrapErrMsg("Unsupported encoding"));
        }
+        int code = this.getErrCode(pSql);
        affectedRows = code;
        if (code < 0) {
            affectedRows = -1;
            if (code == TSDBConstants.JNI_TDENGINE_ERROR) {
-                throw new SQLException(TSDBConstants.WrapErrMsg(this.getErrMsg()), "", this.getErrCode());
+                this.freeResultSet(pSql);
+                throw new SQLException(TSDBConstants.WrapErrMsg(this.getErrMsg(pSql)), "", this.getErrCode(pSql));
            } else {
-                throw new SQLException(TSDBConstants.FixErrMsg(code), "", this.getErrCode());
+                this.freeResultSet(pSql);
+                throw new SQLException(TSDBConstants.FixErrMsg(code), "", this.getErrCode(pSql));
            }
        }
        // Try retrieving result set for the executed SQL using the current connection pointer. If the executed
        // SQL is a DML/DDL which doesn't return a result set, then taosResultSetPointer should be 0L. Otherwise,
        // taosResultSetPointer should be a non-zero value.
-        taosResultSetPointer = this.getResultSetImp(this.taos);
+        taosResultSetPointer = this.getResultSetImp(this.taos, pSql);
        if (taosResultSetPointer != TSDBConstants.JNI_NULL_POINTER) {
            isResultsetClosed = false;
        }
        return code;
    }
-    private native int executeQueryImp(byte[] sqlBytes, long connection);
+    private native long executeQueryImp(byte[] sqlBytes, long connection);
    /**
     * Get recent error code by connection
     */
-    public int getErrCode() {
+    public int getErrCode(Long pSql) {
-        return Math.abs(this.getErrCodeImp(this.taos));
+        return Math.abs(this.getErrCodeImp(this.taos, pSql));
    }
-    private native int getErrCodeImp(long connection);
+    private native int getErrCodeImp(long connection, Long pSql);
    /**
     * Get recent error message by connection
     */
-    public String getErrMsg() {
+    public String getErrMsg(Long pSql) {
-        return this.getErrMsgImp(this.taos);
+        return this.getErrMsgImp(this.taos, pSql);
    }
-    private native String getErrMsgImp(long connection);
+    private native String getErrMsgImp(long connection, Long pSql);
    /**
     * Get resultset pointer
@@ -172,7 +177,7 @@ public class TSDBJNIConnector {
        return taosResultSetPointer;
    }
-    private native long getResultSetImp(long connection);
+    private native long getResultSetImp(long connection, long pSql);
    /**
     * Free resultset operation from C to release resultset pointer by JNI
@@ -212,15 +217,15 @@ public class TSDBJNIConnector {
    /**
     * Get affected rows count
     */
-    public int getAffectedRows() {
+    public int getAffectedRows(Long pSql) {
        int affectedRows = this.affectedRows;
        if (affectedRows < 0) {
-            affectedRows = this.getAffectedRowsImp(this.taos);
+            affectedRows = this.getAffectedRowsImp(this.taos, pSql);
        }
        return affectedRows;
    }
-    private native int getAffectedRowsImp(long connection);
+    private native int getAffectedRowsImp(long connection, Long pSql);
    /**
     * Get schema metadata
@@ -248,7 +253,7 @@ public class TSDBJNIConnector {
    public void closeConnection() throws SQLException {
        int code = this.closeConnectionImp(this.taos);
        if (code < 0) {
-            throw new SQLException(TSDBConstants.FixErrMsg(code), "", this.getErrCode());
+            throw new SQLException(TSDBConstants.FixErrMsg(code), "", this.getErrCode(null));
        } else if (code == 0) {
            this.taos = TSDBConstants.JNI_NULL_POINTER;
        } else {
@@ -261,31 +266,31 @@ public class TSDBJNIConnector {
    /**
     * Subscribe to a table in TSDB
     */
-    public long subscribe(String host, String user, String password, String database, String table, long time, int period) {
+    public long subscribe(String topic, String sql, boolean restart, int period) {
-        return subscribeImp(host, user, password, database, table, time, period);
+        return subscribeImp(this.taos, restart, topic, sql, period);
    }
-    private native long subscribeImp(String host, String user, String password, String database, String table, long time, int period);
+    public native long subscribeImp(long connection, boolean restart, String topic, String sql, int period);
    /**
     * Consume a subscribed table
     */
-    public TSDBResultSetRowData consume(long subscription) {
+    public long consume(long subscription) {
        return this.consumeImp(subscription);
    }
-    private native TSDBResultSetRowData consumeImp(long subscription);
+    private native long consumeImp(long subscription);
    /**
     * Unsubscribe a table
     *
     * @param subscription
     */
-    public void unsubscribe(long subscription) {
+    public void unsubscribe(long subscription, boolean isKeep) {
-        unsubscribeImp(subscription);
+        unsubscribeImp(subscription, isKeep);
    }
-    private native void unsubscribeImp(long subscription);
+    private native void unsubscribeImp(long subscription, boolean isKeep);
    /**
     * Validate if a <I>create table</I> sql statement is correct without actually creating that table

--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSet.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSet.java
@@ -51,47 +51,47 @@ public class TSDBResultSet implements ResultSet {
 	private boolean lastWasNull = false;
 	private final int COLUMN_INDEX_START_VALUE = 1;
-    public TSDBJNIConnector getJniConnector() {
+	public TSDBJNIConnector getJniConnector() {
-        return jniConnector;
+		return jniConnector;
-    }
+	}
-    public void setJniConnector(TSDBJNIConnector jniConnector) {
+	public void setJniConnector(TSDBJNIConnector jniConnector) {
-        this.jniConnector = jniConnector;
+		this.jniConnector = jniConnector;
-    }
+	}
-    public long getResultSetPointer() {
+	public long getResultSetPointer() {
-        return resultSetPointer;
+		return resultSetPointer;
-    }
+	}
-    public void setResultSetPointer(long resultSetPointer) {
+	public void setResultSetPointer(long resultSetPointer) {
-        this.resultSetPointer = resultSetPointer;
+		this.resultSetPointer = resultSetPointer;
-    }
+	}
-    public List<ColumnMetaData> getColumnMetaDataList() {
+	public List<ColumnMetaData> getColumnMetaDataList() {
-        return columnMetaDataList;
+		return columnMetaDataList;
-    }
+	}
-    public void setColumnMetaDataList(List<ColumnMetaData> columnMetaDataList) {
+	public void setColumnMetaDataList(List<ColumnMetaData> columnMetaDataList) {
-        this.columnMetaDataList = columnMetaDataList;
+		this.columnMetaDataList = columnMetaDataList;
-    }
+	}
-    public TSDBResultSetRowData getRowData() {
+	public TSDBResultSetRowData getRowData() {
-        return rowData;
+		return rowData;
-    }
+	}
-    public void setRowData(TSDBResultSetRowData rowData) {
+	public void setRowData(TSDBResultSetRowData rowData) {
-        this.rowData = rowData;
+		this.rowData = rowData;
-    }
+	}
-    public boolean isLastWasNull() {
+	public boolean isLastWasNull() {
-        return lastWasNull;
+		return lastWasNull;
-    }
+	}
-    public void setLastWasNull(boolean lastWasNull) {
+	public void setLastWasNull(boolean lastWasNull) {
-        this.lastWasNull = lastWasNull;
+		this.lastWasNull = lastWasNull;
-    }
+	}
-    public TSDBResultSet() {
+	public TSDBResultSet() {
 	}
 	public TSDBResultSet(TSDBJNIConnector connecter, long resultSetPointer) throws SQLException {
@@ -119,7 +119,7 @@ public class TSDBResultSet implements ResultSet {
 	public boolean next() throws SQLException {
 		if (rowData != null) {
-            this.rowData.clear();
+			this.rowData.clear();
 		}
 		int code = this.jniConnector.fetchRow(this.resultSetPointer, this.rowData);
@@ -154,119 +154,119 @@ public class TSDBResultSet implements ResultSet {
 	public String getString(int columnIndex) throws SQLException {
 		String res = null;
 		int colIndex = getTrueColumnIndex(columnIndex);
-	    this.lastWasNull = this.rowData.wasNull(colIndex);
+		this.lastWasNull = this.rowData.wasNull(colIndex);
-        if (!lastWasNull) {
+		if (!lastWasNull) {
-            res = this.rowData.getString(colIndex, this.columnMetaDataList.get(colIndex).getColType());
+			res = this.rowData.getString(colIndex, this.columnMetaDataList.get(colIndex).getColType());
-        }
+		}
 		return res;
 	}
 	public boolean getBoolean(int columnIndex) throws SQLException {
-	    boolean res = false;
+		boolean res = false;
 		int colIndex = getTrueColumnIndex(columnIndex);
 		this.lastWasNull = this.rowData.wasNull(colIndex);
 		if (!lastWasNull) {
-		    res = this.rowData.getBoolean(colIndex, this.columnMetaDataList.get(colIndex).getColType());
+			res = this.rowData.getBoolean(colIndex, this.columnMetaDataList.get(colIndex).getColType());
-        }
+		}
 		return res;
 	}
 	public byte getByte(int columnIndex) throws SQLException {
-	    byte res = 0;
+		byte res = 0;
 		int colIndex = getTrueColumnIndex(columnIndex);
 		this.lastWasNull = this.rowData.wasNull(colIndex);
 		if (!lastWasNull) {
-		    res = (byte) this.rowData.getInt(colIndex, this.columnMetaDataList.get(colIndex).getColType());
+			res = (byte) this.rowData.getInt(colIndex, this.columnMetaDataList.get(colIndex).getColType());
-        }
+		}
 		return res;
 	}
 	public short getShort(int columnIndex) throws SQLException {
-	    short res = 0;
+		short res = 0;
 		int colIndex = getTrueColumnIndex(columnIndex);
 		this.lastWasNull = this.rowData.wasNull(colIndex);
 		if (!lastWasNull) {
-		    res = (short) this.rowData.getInt(colIndex, this.columnMetaDataList.get(colIndex).getColType());
+			res = (short) this.rowData.getInt(colIndex, this.columnMetaDataList.get(colIndex).getColType());
-        }
+		}
 		return res;
 	}
 	public int getInt(int columnIndex) throws SQLException {
-	    int res = 0;
+		int res = 0;
 		int colIndex = getTrueColumnIndex(columnIndex);
 		this.lastWasNull = this.rowData.wasNull(colIndex);
-        if (!lastWasNull) {
+		if (!lastWasNull) {
-            res = this.rowData.getInt(colIndex, this.columnMetaDataList.get(colIndex).getColType());
+			res = this.rowData.getInt(colIndex, this.columnMetaDataList.get(colIndex).getColType());
-        }
+		}
 		return res;
 	}
 	public long getLong(int columnIndex) throws SQLException {
-	    long res = 0l;
+		long res = 0l;
 		int colIndex = getTrueColumnIndex(columnIndex);
 		this.lastWasNull = this.rowData.wasNull(colIndex);
-        if (!lastWasNull) {
+		if (!lastWasNull) {
-            res = this.rowData.getLong(colIndex, this.columnMetaDataList.get(colIndex).getColType());
+			res = this.rowData.getLong(colIndex, this.columnMetaDataList.get(colIndex).getColType());
-        }
+		}
 		return res;
 	}
 	public float getFloat(int columnIndex) throws SQLException {
-	    float res = 0;
+		float res = 0;
-	    int colIndex = getTrueColumnIndex(columnIndex);
+		int colIndex = getTrueColumnIndex(columnIndex);
 		this.lastWasNull = this.rowData.wasNull(colIndex);
-        if (!lastWasNull) {
+		if (!lastWasNull) {
-            res = this.rowData.getFloat(colIndex, this.columnMetaDataList.get(colIndex).getColType());
+			res = this.rowData.getFloat(colIndex, this.columnMetaDataList.get(colIndex).getColType());
-        }
+		}
 		return res;
 	}
 	public double getDouble(int columnIndex) throws SQLException {
-	    double res = 0;
+		double res = 0;
 		int colIndex = getTrueColumnIndex(columnIndex);
 		this.lastWasNull = this.rowData.wasNull(colIndex);
-        if (!lastWasNull) {
+		if (!lastWasNull) {
-            res = this.rowData.getDouble(colIndex, this.columnMetaDataList.get(colIndex).getColType());
+			res = this.rowData.getDouble(colIndex, this.columnMetaDataList.get(colIndex).getColType());
-        }
+		}
 		return res;
 	}
 	/*
 	 * (non-Javadoc)
-	 * 
+	 *
 	 * @see java.sql.ResultSet#getBigDecimal(int, int)
-	 * 
+	 *
 	 * @deprecated Use {@code getBigDecimal(int columnIndex)} or {@code
 	 * getBigDecimal(String columnLabel)}
 	 */
 	@Deprecated
 	public BigDecimal getBigDecimal(int columnIndex, int scale) throws SQLException {
-	    BigDecimal res = null;
+		BigDecimal res = null;
 		int colIndex = getTrueColumnIndex(columnIndex);
 		this.lastWasNull = this.rowData.wasNull(colIndex);
-        if (!lastWasNull) {
+		if (!lastWasNull) {
-            res = new BigDecimal(this.rowData.getLong(colIndex, this.columnMetaDataList.get(colIndex).getColType()));
+			res = new BigDecimal(this.rowData.getLong(colIndex, this.columnMetaDataList.get(colIndex).getColType()));
-        }
+		}
 		return res;
 	}
 	public byte[] getBytes(int columnIndex) throws SQLException {
-	    byte[] res = null;
+		byte[] res = null;
 		int colIndex = getTrueColumnIndex(columnIndex);
 		this.lastWasNull = this.rowData.wasNull(colIndex);
-        if (!lastWasNull) {
+		if (!lastWasNull) {
-            res = this.rowData.getString(colIndex, this.columnMetaDataList.get(colIndex).getColType()).getBytes();
+			res = this.rowData.getString(colIndex, this.columnMetaDataList.get(colIndex).getColType()).getBytes();
-        }
+		}
 		return res;
 	}
@@ -281,13 +281,13 @@ public class TSDBResultSet implements ResultSet {
 	}
 	public Timestamp getTimestamp(int columnIndex) throws SQLException {
-	    Timestamp res = null;
+		Timestamp res = null;
 		int colIndex = getTrueColumnIndex(columnIndex);
 		this.lastWasNull = this.rowData.wasNull(colIndex);
-        if (!lastWasNull) {
+		if (!lastWasNull) {
-            res = this.rowData.getTimestamp(colIndex);
+			res = this.rowData.getTimestamp(colIndex);
-        }
+		}
 		return res;
 	}
@@ -297,9 +297,9 @@ public class TSDBResultSet implements ResultSet {
 	/*
 	 * (non-Javadoc)
-	 * 
+	 *
 	 * @see java.sql.ResultSet#getUnicodeStream(int)
-	 * 
+	 *
 	 * * @deprecated use <code>getCharacterStream</code> in place of
 	 * <code>getUnicodeStream</code>
 	 */
@@ -409,13 +409,13 @@ public class TSDBResultSet implements ResultSet {
 	}
 	public int findColumn(String columnLabel) throws SQLException {
-        Iterator<ColumnMetaData> colMetaDataIt = this.columnMetaDataList.iterator();
+		Iterator<ColumnMetaData> colMetaDataIt = this.columnMetaDataList.iterator();
-        while (colMetaDataIt.hasNext()) {
+		while (colMetaDataIt.hasNext()) {
-            ColumnMetaData colMetaData = colMetaDataIt.next();
+			ColumnMetaData colMetaData = colMetaDataIt.next();
-            if (colMetaData.getColName() != null && colMetaData.getColName().equalsIgnoreCase(columnLabel)) {
+			if (colMetaData.getColName() != null && colMetaData.getColName().equalsIgnoreCase(columnLabel)) {
-                return colMetaData.getColIndex() + 1;
+				return colMetaData.getColIndex() + 1;
-            }
+			}
-        }
+		}
 		throw new SQLException(TSDBConstants.INVALID_VARIABLES);
 	}
@@ -882,7 +882,7 @@ public class TSDBResultSet implements ResultSet {
 	}
 	public String getNString(int columnIndex) throws SQLException {
-        int colIndex = getTrueColumnIndex(columnIndex);
+		int colIndex = getTrueColumnIndex(columnIndex);
 		return (String) rowData.get(colIndex);
 	}
@@ -1017,17 +1017,17 @@ public class TSDBResultSet implements ResultSet {
 	public <T> T getObject(String columnLabel, Class<T> type) throws SQLException {
 		throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
 	}
 	private int getTrueColumnIndex(int columnIndex) throws SQLException {
 		if (columnIndex < this.COLUMN_INDEX_START_VALUE) {
 			throw new SQLException("Column Index out of range, " + columnIndex + " < " + this.COLUMN_INDEX_START_VALUE);
 		}
 		int numOfCols = this.columnMetaDataList.size();
 		if (columnIndex > numOfCols) {
 			throw new SQLException("Column Index out of range, " + columnIndex + " > " + numOfCols);
 		}
 		return columnIndex - 1;
 	}
 }
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBStatement.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBStatement.java
@@ -27,6 +27,8 @@ public class TSDBStatement implements Statement {
 	/** Timeout for a query */
 	protected int queryTimeout = 0;
+	private Long pSql = 0l;
    /**
     * Status of current statement
     */
@@ -66,21 +68,23 @@ public class TSDBStatement implements Statement {
        if (isClosed) {
            throw new SQLException("Invalid method call on a closed statement.");
        }
-		int res = this.connecter.executeQuery(sql);
+		long res = this.connecter.executeQuery(sql);
 		long resultSetPointer = this.connecter.getResultSet();
 		if (resultSetPointer == TSDBConstants.JNI_CONNECTION_NULL) {
+			this.connecter.freeResultSet(res);
 			throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
 		} else if (resultSetPointer != TSDBConstants.JNI_NULL_POINTER) {
 			this.connecter.freeResultSet();
 			throw new SQLException("The executed SQL is not a DML or a DDL");
 		} else {
-			return res;
+			int num = this.connecter.getAffectedRows(res);
+			return num;
 		}
 	}
-	public String getErrorMsg() {
+	public String getErrorMsg(long pSql) {
-		return this.connecter.getErrMsg();
+		return this.connecter.getErrMsg(pSql);
 	}
 	public void close() throws SQLException {
@@ -170,7 +174,7 @@ public class TSDBStatement implements Statement {
        if (isClosed) {
            throw new SQLException("Invalid method call on a closed statement.");
        }
-		return this.connecter.getAffectedRows();
+		return this.connecter.getAffectedRows(this.pSql);
 	}
 	public boolean getMoreResults() throws SQLException {

--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBSubscribe.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBSubscribe.java
+/***************************************************************************
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *****************************************************************************/
+package com.taosdata.jdbc;
+import javax.management.OperationsException;
+import java.sql.SQLException;
+import java.util.Map;
+import java.util.TimerTask;
+import java.util.concurrent.*;
+public class TSDBSubscribe {
+    private TSDBJNIConnector connecter = null;
+    private static ScheduledExecutorService pool;
+    private static Map<Long, TSDBTimerTask> timerTaskMap = new ConcurrentHashMap<>();
+    private static Map<Long, ScheduledFuture> scheduledMap = new ConcurrentHashMap();
+    private static class TimerInstance {
+        private static final ScheduledExecutorService instance = Executors.newScheduledThreadPool(1);
+    }
+    public static ScheduledExecutorService getTimerInstance() {
+        return TimerInstance.instance;
+    }
+    public TSDBSubscribe(TSDBJNIConnector connecter) throws SQLException {
+        if (null != connecter) {
+            this.connecter = connecter;
+        } else {
+            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+        }
+    }
+    /**
+     * sync subscribe
+     *
+     * @param topic
+     * @param sql
+     * @param restart
+     * @param period
+     * @throws SQLException
+     */
+    public long subscribe(String topic, String sql, boolean restart, int period) throws SQLException {
+        if (this.connecter.isClosed()) {
+            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+        }
+        if (period < 1000) {
+            throw new SQLException(TSDBConstants.WrapErrMsg(TSDBConstants.INVALID_VARIABLES));
+        }
+        return this.connecter.subscribe(topic, sql, restart, period);
+    }
+    /**
+     * async subscribe
+     *
+     * @param topic
+     * @param sql
+     * @param restart
+     * @param period
+     * @param callBack
+     * @throws SQLException
+     */
+    public long subscribe(String topic, String sql, boolean restart, int period, TSDBSubscribeCallBack callBack) throws SQLException {
+        if (this.connecter.isClosed()) {
+            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+        }
+        final long subscription = this.connecter.subscribe(topic, sql, restart, period);
+        if (null != callBack) {
+            pool = getTimerInstance();
+            TSDBTimerTask timerTask = new TSDBTimerTask(subscription, callBack);
+            timerTaskMap.put(subscription, timerTask);
+            ScheduledFuture scheduledFuture = pool.scheduleAtFixedRate(timerTask, 1, 1000, TimeUnit.MILLISECONDS);
+            scheduledMap.put(subscription, scheduledFuture);
+        }
+        return subscription;
+    }
+    public TSDBResultSet consume(long subscription) throws OperationsException, SQLException {
+        if (this.connecter.isClosed()) {
+            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+        }
+        if (0 == subscription) {
+            throw new OperationsException("Invalid use of consume");
+        }
+        long resultSetPointer = this.connecter.consume(subscription);
+        if (resultSetPointer == TSDBConstants.JNI_CONNECTION_NULL) {
+            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+        } else if (resultSetPointer == TSDBConstants.JNI_NULL_POINTER) {
+            return null;
+        } else {
+            return new TSDBResultSet(this.connecter, resultSetPointer);
+        }
+    }
+    /**
+     * cancel subscribe
+     *
+     * @param subscription
+     * @param isKeep
+     * @throws SQLException
+     */
+    public void unsubscribe(long subscription, boolean isKeep) throws SQLException {
+        if (this.connecter.isClosed()) {
+            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+        }
+        if (null != timerTaskMap.get(subscription)) {
+            synchronized (timerTaskMap.get(subscription)) {
+                while (1 == timerTaskMap.get(subscription).getState()) {
+                    try {
+                        Thread.sleep(10);
+                    } catch (Exception e) {
+                        throw new RuntimeException(e);
+                    }
+                }
+                timerTaskMap.get(subscription).setState(2);
+                if (!timerTaskMap.isEmpty() && timerTaskMap.containsKey(subscription)) {
+                    timerTaskMap.get(subscription).cancel();
+                    timerTaskMap.remove(subscription);
+                    scheduledMap.get(subscription).cancel(false);
+                    scheduledMap.remove(subscription);
+                }
+                this.connecter.unsubscribe(subscription, isKeep);
+            }
+        } else {
+            this.connecter.unsubscribe(subscription, isKeep);
+        }
+    }
+    class TSDBTimerTask extends TimerTask {
+        private long subscription;
+        private TSDBSubscribeCallBack callBack;
+        // 0: not running 1: running 2: cancel
+        private int state = 0;
+        public TSDBTimerTask(long subscription, TSDBSubscribeCallBack callBack) {
+            this.subscription = subscription;
+            this.callBack = callBack;
+        }
+        public int getState() {
+            return this.state;
+        }
+        public void setState(int state) {
+            this.state = state;
+        }
+        @Override
+        public void run() {
+            synchronized (this) {
+                if (2 == state) {
+                    return;
+                }
+                state = 1;
+                try {
+                    TSDBResultSet resultSet = consume(subscription);
+                    callBack.invoke(resultSet);
+                } catch (Exception e) {
+                    this.cancel();
+                    throw new RuntimeException(e);
+                }
+                state = 0;
+            }
+        }
+    }
+}
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBSubscribeCallBack.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBSubscribeCallBack.java
+/***************************************************************************
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *****************************************************************************/
+package com.taosdata.jdbc;
+public interface TSDBSubscribeCallBack {
+    void invoke(TSDBResultSet resultSet);
+}
--- a/src/connector/jdbc/src/test/java/TestAsyncTSDBSubscribe.java
+++ b/src/connector/jdbc/src/test/java/TestAsyncTSDBSubscribe.java
+import com.taosdata.jdbc.*;
+import org.apache.commons.lang3.StringUtils;
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.util.Properties;
+public class TestAsyncTSDBSubscribe {
+    public static void main(String[] args) {
+        String usage = "java -cp taos-jdbcdriver-1.0.3_dev-dist.jar com.taosdata.jdbc.TSDBSubscribe -db dbName -topic topicName " +
+                "-tname tableName -h host";
+        if (args.length < 2) {
+            System.err.println(usage);
+            return;
+        }
+        String dbName = "";
+        String tName = "";
+        String host = "localhost";
+        String topic = "";
+        for (int i = 0; i < args.length; i++) {
+            if ("-db".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                dbName = args[++i];
+            }
+            if ("-tname".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                tName = args[++i];
+            }
+            if ("-h".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                host = args[++i];
+            }
+            if ("-topic".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                topic = args[++i];
+            }
+        }
+        if (StringUtils.isEmpty(dbName) || StringUtils.isEmpty(tName) || StringUtils.isEmpty(topic)) {
+            System.err.println(usage);
+            return;
+        }
+        Connection connection = null;
+        TSDBSubscribe subscribe = null;
+        long subscribId = 0;
+        try {
+            Class.forName("com.taosdata.jdbc.TSDBDriver");
+            Properties properties = new Properties();
+            properties.setProperty(TSDBDriver.PROPERTY_KEY_HOST, host);
+            connection = DriverManager.getConnection("jdbc:TAOS://" + host + ":0/" + dbName + "?user=root&password=taosdata", properties);
+            String rawSql = "select * from " + tName + ";";
+            subscribe = ((TSDBConnection) connection).createSubscribe();
+            subscribId = subscribe.subscribe(topic, rawSql, false, 1000, new CallBack("first"));
+            long subscribId2 = subscribe.subscribe("test", rawSql, false, 1000, new CallBack("second"));
+            int a = 0;
+            Thread.sleep(2000);
+            subscribe.unsubscribe(subscribId, true);
+            System.err.println("cancel subscribe");
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+    private static class CallBack implements TSDBSubscribeCallBack {
+        private String name = "";
+        public CallBack(String name) {
+            this.name = name;
+        }
+        @Override
+        public void invoke(TSDBResultSet resultSet) {
+            try {
+                while (null !=resultSet && resultSet.next()) {
+                    System.out.print("callback_" + name + ": ");
+                    for (int i = 1; i <= resultSet.getMetaData().getColumnCount(); i++) {
+                        System.out.printf(i + ": " + resultSet.getString(i) + "\t");
+                    }
+                    System.out.println();
+                }
+            } catch (Exception e) {
+                e.printStackTrace();
+            }
+        }
+    }
+}
--- a/src/connector/jdbc/src/test/java/TestPreparedStatement.java
+++ b/src/connector/jdbc/src/test/java/TestPreparedStatement.java
@@ -10,9 +10,9 @@ public class TestPreparedStatement {
        try {
            Class.forName("com.taosdata.jdbc.TSDBDriver");
            Properties properties = new Properties();
-            properties.setProperty(TSDBDriver.PROPERTY_KEY_HOST, "192.168.1.117");
+            properties.setProperty(TSDBDriver.PROPERTY_KEY_HOST, "localhost");
-            Connection connection = DriverManager.getConnection("jdbc:TAOS://192.168.1.117:0/?user=root&password=taosdata", properties);
+            Connection connection = DriverManager.getConnection("jdbc:TAOS://localhost:0/?user=root&password=taosdata", properties);
-            String rawSql = "SELECT ts, c1 FROM (select c1, ts from db.tb1) SUB_QRY";
+            String rawSql = "select * from test.log0601";
 //            String[] params = new String[]{"ts", "c1"};
            PreparedStatement pstmt = (TSDBPreparedStatement) connection.prepareStatement(rawSql);
            ResultSet resSet = pstmt.executeQuery();

--- a/src/connector/jdbc/src/test/java/TestTSDBSubscribe.java
+++ b/src/connector/jdbc/src/test/java/TestTSDBSubscribe.java
+import com.taosdata.jdbc.TSDBConnection;
+import com.taosdata.jdbc.TSDBDriver;
+import com.taosdata.jdbc.TSDBResultSet;
+import com.taosdata.jdbc.TSDBSubscribe;
+import org.apache.commons.lang3.StringUtils;
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.util.Properties;
+public class TestTSDBSubscribe {
+    public static void main(String[] args) throws Exception {
+        String usage = "java -cp taos-jdbcdriver-1.0.3_dev-dist.jar com.taosdata.jdbc.TSDBSubscribe -db dbName " +
+                "-topic topicName -tname tableName -h host";
+        if (args.length < 2) {
+            System.err.println(usage);
+            return;
+        }
+        String dbName = "";
+        String tName = "";
+        String host = "localhost";
+        String topic = "";
+        for (int i = 0; i < args.length; i++) {
+            if ("-db".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                dbName = args[++i];
+            }
+            if ("-tname".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                tName = args[++i];
+            }
+            if ("-h".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                host = args[++i];
+            }
+            if ("-topic".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                topic = args[++i];
+            }
+        }
+        if (StringUtils.isEmpty(dbName) || StringUtils.isEmpty(tName) || StringUtils.isEmpty(topic)) {
+            System.err.println(usage);
+            return;
+        }
+        Connection connection = null;
+        TSDBSubscribe subscribe = null;
+        long subscribId = 0;
+        try {
+            Class.forName("com.taosdata.jdbc.TSDBDriver");
+            Properties properties = new Properties();
+            properties.setProperty(TSDBDriver.PROPERTY_KEY_HOST, host);
+            connection = DriverManager.getConnection("jdbc:TAOS://" + host + ":0/" + dbName + "?user=root&password=taosdata"
+                    , properties);
+            String rawSql = "select * from " + tName + ";";
+            subscribe = ((TSDBConnection) connection).createSubscribe();
+            subscribId = subscribe.subscribe(topic, rawSql, false, 1000);
+            int a = 0;
+            while (true) {
+                Thread.sleep(900);
+                TSDBResultSet resSet = subscribe.consume(subscribId);
+                while (resSet.next()) {
+                    for (int i = 1; i <= resSet.getMetaData().getColumnCount(); i++) {
+                        System.out.printf(i + ": " + resSet.getString(i) + "\t");
+                    }
+                    System.out.println("\n======" + a + "==========");
+                }
+                a++;
+                if (a >= 10) {
+                    break;
+                }
+            }
+        } catch (Exception e) {
+            e.printStackTrace();
+        } finally {
+            if (null != subscribe && 0 != subscribId) {
+                subscribe.unsubscribe(subscribId, true);
+            }
+            if (null != connection) {
+                connection.close();
+            }
+        }
+    }
+}
--- a/src/connector/python/linux/python2/taos/cinterface.py
+++ b/src/connector/python/linux/python2/taos/cinterface.py
@@ -142,12 +142,14 @@ class CTaosInterface(object):
    libtaos.taos_fetch_fields.restype = ctypes.POINTER(TaosField)
    libtaos.taos_init.restype = None
    libtaos.taos_connect.restype = ctypes.c_void_p
-    libtaos.taos_use_result.restype = ctypes.c_void_p
+    #libtaos.taos_use_result.restype = ctypes.c_void_p
    libtaos.taos_fetch_row.restype = ctypes.POINTER(ctypes.c_void_p)
    libtaos.taos_errstr.restype = ctypes.c_char_p
    libtaos.taos_subscribe.restype = ctypes.c_void_p
    libtaos.taos_consume.restype = ctypes.c_void_p
    libtaos.taos_fetch_lengths.restype = ctypes.c_void_p
+    libtaos.taos_free_result.restype = None
+    libtaos.taos_errno.restype = ctypes.c_int
    def __init__(self, config=None):
        '''
@@ -249,12 +251,12 @@ class CTaosInterface(object):
            raise AttributeError("sql is expected as a string")
        # finally:
        #     CTaosInterface.libtaos.close(connection)
    @staticmethod
-    def affectedRows(connection):
+    def affectedRows(result):
        """The affected rows after runing query
        """
-        return CTaosInterface.libtaos.taos_affected_rows(connection)
+        return CTaosInterface.libtaos.taos_affected_rows(result)
    @staticmethod
    def subscribe(connection, restart, topic, sql, interval):
@@ -292,18 +294,17 @@ class CTaosInterface(object):
        CTaosInterface.libtaos.taos_unsubscribe(sub, 1 if keepProgress else 0)
    @staticmethod
-    def useResult(connection):
+    def useResult(result):
        '''Use result after calling self.query
        '''
-        result = ctypes.c_void_p(CTaosInterface.libtaos.taos_use_result(connection))
        fields = []
        pfields = CTaosInterface.fetchFields(result)
-        for i in range(CTaosInterface.fieldsCount(connection)):
+        for i in range(CTaosInterface.fieldsCount(result)):
            fields.append({'name': pfields[i].name.decode('utf-8'),
                           'bytes': pfields[i].bytes,
                           'type': ord(pfields[i].type)})
-        return result, fields
+        return fields
    @staticmethod
    def fetchBlock(result, fields):
@@ -337,8 +338,8 @@ class CTaosInterface(object):
        result.value = None
    @staticmethod
-    def fieldsCount(connection):
+    def fieldsCount(result):
-        return CTaosInterface.libtaos.taos_field_count(connection)
+        return CTaosInterface.libtaos.taos_field_count(result)
    @staticmethod
    def fetchFields(result):
@@ -386,29 +387,30 @@ class CTaosInterface(object):
    #         return (ctypes.cast(data,  ctypes.c_char_p).value).rstrip('\x00')
    @staticmethod
-    def errno(connection):
+    def errno(result):
        """Return the error number.
        """
-        return CTaosInterface.libtaos.taos_errno(connection)
+        return CTaosInterface.libtaos.taos_errno(result)
    @staticmethod
-    def errStr(connection):
+    def errStr(result):
        """Return the error styring
        """
-        return CTaosInterface.libtaos.taos_errstr(connection)
+        return CTaosInterface.libtaos.taos_errstr(result)
 if __name__ == '__main__':
    cinter = CTaosInterface()
    conn = cinter.connect()
+    result = cinter.query(conn, 'show databases')
-    print('Query return value: {}'.format(cinter.query(conn, 'show databases')))
+    print('Query Affected rows: {}'.format(cinter.affectedRows(result)))
-    print('Affected rows: {}'.format(cinter.affectedRows(conn)))
-    result, des = CTaosInterface.useResult(conn)
+    fields = CTaosInterface.useResult(result)
-    data, num_of_rows = CTaosInterface.fetchBlock(result, des)
+    data, num_of_rows = CTaosInterface.fetchBlock(result, fields)
    print(data)
+    cinter.freeresult(result)
    cinter.close(conn)
\ No newline at end of file
--- a/src/connector/python/linux/python2/taos/connection.py
+++ b/src/connector/python/linux/python2/taos/connection.py
@@ -78,9 +78,7 @@ class TDengineConnection(object):
    def clear_result_set(self):
        """Clear unused result set on this connection.
        """
-        result = self._chandle.useResult(self._conn)[0]
+        pass
-        if result:
-            self._chandle.freeResult(result)
 if __name__ == "__main__":
    conn = TDengineConnection(host='192.168.1.107')

--- a/src/connector/python/linux/python2/taos/constants.py
+++ b/src/connector/python/linux/python2/taos/constants.py
@@ -28,6 +28,6 @@ class FieldType(object):
    C_FLOAT_NULL = float('nan')
    C_DOUBLE_NULL = float('nan')
    C_BINARY_NULL = bytearray([int('0xff', 16)])
-    # Time precision definition
+    # Timestamp precision definition
    C_TIMESTAMP_MILLI = 0
    C_TIMESTAMP_MICRO = 1
--- a/src/connector/python/linux/python2/taos/cursor.py
+++ b/src/connector/python/linux/python2/taos/cursor.py
@@ -116,25 +116,30 @@ class TDengineCursor(object):
        if params is not None:
            pass
-        res = CTaosInterface.query(self._connection._conn, stmt)
+        # global querySeqNum
+        # querySeqNum += 1
+        # localSeqNum = querySeqNum # avoid raice condition
+        # print("   >> Exec Query ({}): {}".format(localSeqNum, str(stmt)))
+        self._result = CTaosInterface.query(self._connection._conn, stmt)
+        # print("   << Query ({}) Exec Done".format(localSeqNum))
        if (self._logfile):
            with open(self._logfile, "a") as logfile:
                logfile.write("%s;\n" % operation)
-        if res == 0:
+        errno = CTaosInterface.libtaos.taos_errno(self._result)
-            if CTaosInterface.fieldsCount(self._connection._conn) == 0:
+        if errno == 0:
+            if CTaosInterface.fieldsCount(self._result) == 0:
                self._affected_rows += CTaosInterface.affectedRows(
-                    self._connection._conn)
+                    self._result )
-                return CTaosInterface.affectedRows(self._connection._conn)
+                return CTaosInterface.affectedRows(self._result )
            else:
-                self._result, self._fields = CTaosInterface.useResult(
+                self._fields = CTaosInterface.useResult(
-                    self._connection._conn)
+                    self._result)
                return self._handle_result()
        else:
            raise ProgrammingError(
                CTaosInterface.errStr(
-                    self._connection._conn))
+                    self._result ))
    def executemany(self, operation, seq_of_parameters):
        """Prepare a database operation (query or command) and then execute it against all parameter sequences or mappings found in the sequence seq_of_parameters.

--- a/src/connector/python/linux/python3/taos/cinterface.py
+++ b/src/connector/python/linux/python3/taos/cinterface.py
@@ -142,12 +142,14 @@ class CTaosInterface(object):
    libtaos.taos_fetch_fields.restype = ctypes.POINTER(TaosField)
    libtaos.taos_init.restype = None
    libtaos.taos_connect.restype = ctypes.c_void_p
-    libtaos.taos_use_result.restype = ctypes.c_void_p
+    #libtaos.taos_use_result.restype = ctypes.c_void_p
    libtaos.taos_fetch_row.restype = ctypes.POINTER(ctypes.c_void_p)
    libtaos.taos_errstr.restype = ctypes.c_char_p
    libtaos.taos_subscribe.restype = ctypes.c_void_p
    libtaos.taos_consume.restype = ctypes.c_void_p
    libtaos.taos_fetch_lengths.restype = ctypes.c_void_p
+    libtaos.taos_free_result.restype = None
+    libtaos.taos_errno.restype = ctypes.c_int
    def __init__(self, config=None):
        '''
@@ -249,12 +251,12 @@ class CTaosInterface(object):
            raise AttributeError("sql is expected as a string")
        # finally:
        #     CTaosInterface.libtaos.close(connection)
    @staticmethod
-    def affectedRows(connection):
+    def affectedRows(result):
        """The affected rows after runing query
        """
-        return CTaosInterface.libtaos.taos_affected_rows(connection)
+        return CTaosInterface.libtaos.taos_affected_rows(result)
    @staticmethod
    def subscribe(connection, restart, topic, sql, interval):
@@ -292,18 +294,17 @@ class CTaosInterface(object):
        CTaosInterface.libtaos.taos_unsubscribe(sub, 1 if keepProgress else 0)
    @staticmethod
-    def useResult(connection):
+    def useResult(result):
        '''Use result after calling self.query
        '''
-        result = ctypes.c_void_p(CTaosInterface.libtaos.taos_use_result(connection))
        fields = []
        pfields = CTaosInterface.fetchFields(result)
-        for i in range(CTaosInterface.fieldsCount(connection)):
+        for i in range(CTaosInterface.fieldsCount(result)):
            fields.append({'name': pfields[i].name.decode('utf-8'),
                           'bytes': pfields[i].bytes,
                           'type': ord(pfields[i].type)})
-        return result, fields
+        return fields
    @staticmethod
    def fetchBlock(result, fields):
@@ -337,8 +338,8 @@ class CTaosInterface(object):
        result.value = None
    @staticmethod
-    def fieldsCount(connection):
+    def fieldsCount(result):
-        return CTaosInterface.libtaos.taos_field_count(connection)
+        return CTaosInterface.libtaos.taos_field_count(result)
    @staticmethod
    def fetchFields(result):
@@ -386,29 +387,30 @@ class CTaosInterface(object):
    #         return (ctypes.cast(data,  ctypes.c_char_p).value).rstrip('\x00')
    @staticmethod
-    def errno(connection):
+    def errno(result):
        """Return the error number.
        """
-        return CTaosInterface.libtaos.taos_errno(connection)
+        return CTaosInterface.libtaos.taos_errno(result)
    @staticmethod
-    def errStr(connection):
+    def errStr(result):
        """Return the error styring
        """
-        return CTaosInterface.libtaos.taos_errstr(connection).decode('utf-8')
+        return CTaosInterface.libtaos.taos_errstr(result).decode('utf-8')
 if __name__ == '__main__':
    cinter = CTaosInterface()
    conn = cinter.connect()
+    result = cinter.query(conn, 'show databases')
-    print('Query return value: {}'.format(cinter.query(conn, 'show databases')))
+    print('Query Affected rows: {}'.format(cinter.affectedRows(result)))
-    print('Affected rows: {}'.format(cinter.affectedRows(conn)))
-    result, des = CTaosInterface.useResult(conn)
+    fields = CTaosInterface.useResult(result)
-    data, num_of_rows = CTaosInterface.fetchBlock(result, des)
+    data, num_of_rows = CTaosInterface.fetchBlock(result, fields)
    print(data)
+    cinter.freeresult(result)
    cinter.close(conn)
\ No newline at end of file
--- a/src/connector/python/linux/python3/taos/connection.py
+++ b/src/connector/python/linux/python3/taos/connection.py
@@ -78,9 +78,7 @@ class TDengineConnection(object):
    def clear_result_set(self):
        """Clear unused result set on this connection.
        """
-        result = self._chandle.useResult(self._conn)[0]
+        pass
-        if result:
-            self._chandle.freeResult(result)
 if __name__ == "__main__":
    conn = TDengineConnection(host='192.168.1.107')

--- a/src/connector/python/linux/python3/taos/cursor.py
+++ b/src/connector/python/linux/python3/taos/cursor.py
@@ -122,26 +122,26 @@ class TDengineCursor(object):
        # querySeqNum += 1
        # localSeqNum = querySeqNum # avoid raice condition
        # print("   >> Exec Query ({}): {}".format(localSeqNum, str(stmt)))
-        res = CTaosInterface.query(self._connection._conn, stmt)
+        self._result = CTaosInterface.query(self._connection._conn, stmt)
        # print("   << Query ({}) Exec Done".format(localSeqNum))
        if (self._logfile):
            with open(self._logfile, "a") as logfile:
                logfile.write("%s;\n" % operation)
-        if res == 0:
+        errno = CTaosInterface.libtaos.taos_errno(self._result)
-            if CTaosInterface.fieldsCount(self._connection._conn) == 0:
+        if errno == 0:
+            if CTaosInterface.fieldsCount(self._result) == 0:
                self._affected_rows += CTaosInterface.affectedRows(
-                    self._connection._conn)
+                    self._result )
-                return CTaosInterface.affectedRows(self._connection._conn)
+                return CTaosInterface.affectedRows(self._result )
            else:
-                self._result, self._fields = CTaosInterface.useResult(
+                self._fields = CTaosInterface.useResult(
-                    self._connection._conn)
+                    self._result)
                return self._handle_result()
        else:
            raise ProgrammingError(
                CTaosInterface.errStr(
-                    self._connection._conn))
+                    self._result ))
    def executemany(self, operation, seq_of_parameters):
        """Prepare a database operation (query or command) and then execute it against all parameter sequences or mappings found in the sequence seq_of_parameters.

--- a/src/connector/python/linux/python3/test.py
+++ b/src/connector/python/linux/python3/test.py
+from taos.cinterface import CTaosInterface
+from taos.error import *
+from taos.subscription import TDengineSubscription
+from taos.connection import TDengineConnection
+if __name__ == '__main__':
+    conn = TDengineConnection(
+        host="127.0.0.1", user="root", password="taosdata", database="test")
+    # Generate a cursor object to run SQL commands
+    sub = conn.subscribe(False, "test", "select * from log0601;", 1000)
+    for i in range(100):
+        print(i)
+        data = sub.consume()
+        for d in data:
+            print(d)
+    sub.close()
+    conn.close()
--- a/src/connector/python/windows/python2/taos/cinterface.py
+++ b/src/connector/python/windows/python2/taos/cinterface.py
@@ -142,12 +142,14 @@ class CTaosInterface(object):
    libtaos.taos_fetch_fields.restype = ctypes.POINTER(TaosField)
    libtaos.taos_init.restype = None
    libtaos.taos_connect.restype = ctypes.c_void_p
-    libtaos.taos_use_result.restype = ctypes.c_void_p
+    #libtaos.taos_use_result.restype = ctypes.c_void_p
    libtaos.taos_fetch_row.restype = ctypes.POINTER(ctypes.c_void_p)
    libtaos.taos_errstr.restype = ctypes.c_char_p
    libtaos.taos_subscribe.restype = ctypes.c_void_p
    libtaos.taos_consume.restype = ctypes.c_void_p
    libtaos.taos_fetch_lengths.restype = ctypes.c_void_p
+    libtaos.taos_free_result.restype = None
+    libtaos.taos_errno.restype = ctypes.c_int
    def __init__(self, config=None):
        '''
@@ -251,10 +253,10 @@ class CTaosInterface(object):
        #     CTaosInterface.libtaos.close(connection)
    @staticmethod
-    def affectedRows(connection):
+    def affectedRows(result):
        """The affected rows after runing query
        """
-        return CTaosInterface.libtaos.taos_affected_rows(connection)
+        return CTaosInterface.libtaos.taos_affected_rows(result)
    @staticmethod
    def subscribe(connection, restart, topic, sql, interval):
@@ -292,18 +294,17 @@ class CTaosInterface(object):
        CTaosInterface.libtaos.taos_unsubscribe(sub, 1 if keepProgress else 0)
    @staticmethod
-    def useResult(connection):
+    def useResult(result):
        '''Use result after calling self.query
        '''
-        result = ctypes.c_void_p(CTaosInterface.libtaos.taos_use_result(connection))
        fields = []
        pfields = CTaosInterface.fetchFields(result)
-        for i in range(CTaosInterface.fieldsCount(connection)):
+        for i in range(CTaosInterface.fieldsCount(result)):
            fields.append({'name': pfields[i].name.decode('utf-8'),
                           'bytes': pfields[i].bytes,
                           'type': ord(pfields[i].type)})
-        return result, fields
+        return fields
    @staticmethod
    def fetchBlock(result, fields):
@@ -337,8 +338,8 @@ class CTaosInterface(object):
        result.value = None
    @staticmethod
-    def fieldsCount(connection):
+    def fieldsCount(result):
-        return CTaosInterface.libtaos.taos_field_count(connection)
+        return CTaosInterface.libtaos.taos_field_count(result)
    @staticmethod
    def fetchFields(result):
@@ -386,29 +387,30 @@ class CTaosInterface(object):
    #         return (ctypes.cast(data,  ctypes.c_char_p).value).rstrip('\x00')
    @staticmethod
-    def errno(connection):
+    def errno(result):
        """Return the error number.
        """
-        return CTaosInterface.libtaos.taos_errno(connection)
+        return CTaosInterface.libtaos.taos_errno(result)
    @staticmethod
-    def errStr(connection):
+    def errStr(result):
        """Return the error styring
        """
-        return CTaosInterface.libtaos.taos_errstr(connection)
+        return CTaosInterface.libtaos.taos_errstr(result)
 if __name__ == '__main__':
    cinter = CTaosInterface()
    conn = cinter.connect()
+    result = cinter.query(conn, 'show databases')
-    print('Query return value: {}'.format(cinter.query(conn, 'show databases')))
+    print('Query Affected rows: {}'.format(cinter.affectedRows(result)))
-    print('Affected rows: {}'.format(cinter.affectedRows(conn)))
-    result, des = CTaosInterface.useResult(conn)
+    fields = CTaosInterface.useResult(result)
-    data, num_of_rows = CTaosInterface.fetchBlock(result, des)
+    data, num_of_rows = CTaosInterface.fetchBlock(result, fields)
    print(data)
+    cinter.freeresult(result)
    cinter.close(conn)
\ No newline at end of file
--- a/src/connector/python/windows/python2/taos/connection.py
+++ b/src/connector/python/windows/python2/taos/connection.py
@@ -79,9 +79,7 @@ class TDengineConnection(object):
    def clear_result_set(self):
        """Clear unused result set on this connection.
        """
-        result = self._chandle.useResult(self._conn)[0]
+        pass
-        if result:
-            self._chandle.freeResult(result)
 if __name__ == "__main__":
    conn = TDengineConnection(host='192.168.1.107')

--- a/src/connector/python/windows/python2/taos/cursor.py
+++ b/src/connector/python/windows/python2/taos/cursor.py
@@ -109,16 +109,17 @@ class TDengineCursor(object):
        if params is not None:
            pass
-        res = CTaosInterface.query(self._connection._conn, stmt)
+        self._result = CTaosInterface.query(self._connection._conn, stmt)
-        if res == 0:
+        errno = CTaosInterface.libtaos.taos_errno(self._result)
-            if CTaosInterface.fieldsCount(self._connection._conn) == 0:
+        if errno == 0:
-                self._affected_rows += CTaosInterface.affectedRows(self._connection._conn)
+            if CTaosInterface.fieldsCount(self._result) == 0:
-                return CTaosInterface.affectedRows(self._connection._conn)
+                self._affected_rows += CTaosInterface.affectedRows(self._result)
+                return CTaosInterface.affectedRows(self._result )
            else:
-                self._result, self._fields = CTaosInterface.useResult(self._connection._conn)
+                self._fields = CTaosInterface.useResult(self._result)
                return self._handle_result()
        else:
-            raise ProgrammingError(CTaosInterface.errStr(self._connection._conn))
+            raise ProgrammingError(CTaosInterface.errStr(self._result))
    def executemany(self, operation, seq_of_parameters):
        """Prepare a database operation (query or command) and then execute it against all parameter sequences or mappings found in the sequence seq_of_parameters.

--- a/src/connector/python/windows/python3/taos/cinterface.py
+++ b/src/connector/python/windows/python3/taos/cinterface.py
@@ -142,12 +142,14 @@ class CTaosInterface(object):
    libtaos.taos_fetch_fields.restype = ctypes.POINTER(TaosField)
    libtaos.taos_init.restype = None
    libtaos.taos_connect.restype = ctypes.c_void_p
-    libtaos.taos_use_result.restype = ctypes.c_void_p
+    #libtaos.taos_use_result.restype = ctypes.c_void_p
    libtaos.taos_fetch_row.restype = ctypes.POINTER(ctypes.c_void_p)
    libtaos.taos_errstr.restype = ctypes.c_char_p
    libtaos.taos_subscribe.restype = ctypes.c_void_p
    libtaos.taos_consume.restype = ctypes.c_void_p
    libtaos.taos_fetch_lengths.restype = ctypes.c_void_p
+    libtaos.taos_free_result.restype = None
+    libtaos.taos_errno.restype = ctypes.c_int
    def __init__(self, config=None):
        '''
@@ -251,10 +253,10 @@ class CTaosInterface(object):
        #     CTaosInterface.libtaos.close(connection)
    @staticmethod
-    def affectedRows(connection):
+    def affectedRows(result):
        """The affected rows after runing query
        """
-        return CTaosInterface.libtaos.taos_affected_rows(connection)
+        return CTaosInterface.libtaos.taos_affected_rows(result)
    @staticmethod
    def subscribe(connection, restart, topic, sql, interval):
@@ -292,18 +294,17 @@ class CTaosInterface(object):
        CTaosInterface.libtaos.taos_unsubscribe(sub, 1 if keepProgress else 0)
    @staticmethod
-    def useResult(connection):
+    def useResult(result):
        '''Use result after calling self.query
        '''
-        result = ctypes.c_void_p(CTaosInterface.libtaos.taos_use_result(connection))
        fields = []
        pfields = CTaosInterface.fetchFields(result)
-        for i in range(CTaosInterface.fieldsCount(connection)):
+        for i in range(CTaosInterface.fieldsCount(result)):
            fields.append({'name': pfields[i].name.decode('utf-8'),
                           'bytes': pfields[i].bytes,
                           'type': ord(pfields[i].type)})
-        return result, fields
+        return fields
    @staticmethod
    def fetchBlock(result, fields):
@@ -337,8 +338,8 @@ class CTaosInterface(object):
        result.value = None
    @staticmethod
-    def fieldsCount(connection):
+    def fieldsCount(result):
-        return CTaosInterface.libtaos.taos_field_count(connection)
+        return CTaosInterface.libtaos.taos_field_count(result)
    @staticmethod
    def fetchFields(result):
@@ -386,29 +387,30 @@ class CTaosInterface(object):
    #         return (ctypes.cast(data,  ctypes.c_char_p).value).rstrip('\x00')
    @staticmethod
-    def errno(connection):
+    def errno(result):
        """Return the error number.
        """
-        return CTaosInterface.libtaos.taos_errno(connection)
+        return CTaosInterface.libtaos.taos_errno(result)
    @staticmethod
-    def errStr(connection):
+    def errStr(result):
        """Return the error styring
        """
-        return CTaosInterface.libtaos.taos_errstr(connection).decode('utf-8')
+        return CTaosInterface.libtaos.taos_errstr(result).decode('utf-8')
 if __name__ == '__main__':
    cinter = CTaosInterface()
    conn = cinter.connect()
+    result = cinter.query(conn, 'show databases')
-    print('Query return value: {}'.format(cinter.query(conn, 'show databases')))
+    print('Query Affected rows: {}'.format(cinter.affectedRows(result)))
-    print('Affected rows: {}'.format(cinter.affectedRows(conn)))
-    result, des = CTaosInterface.useResult(conn)
+    fields = CTaosInterface.useResult(result)
-    data, num_of_rows = CTaosInterface.fetchBlock(result, des)
+    data, num_of_rows = CTaosInterface.fetchBlock(result, fields)
    print(data)
+    cinter.freeresult(result)
    cinter.close(conn)
\ No newline at end of file
--- a/src/connector/python/windows/python3/taos/connection.py
+++ b/src/connector/python/windows/python3/taos/connection.py
@@ -79,9 +79,7 @@ class TDengineConnection(object):
    def clear_result_set(self):
        """Clear unused result set on this connection.
        """
-        result = self._chandle.useResult(self._conn)[0]
+        pass
-        if result:
-            self._chandle.freeResult(result)
 if __name__ == "__main__":
    conn = TDengineConnection(host='192.168.1.107')

--- a/src/connector/python/windows/python3/taos/cursor.py
+++ b/src/connector/python/windows/python3/taos/cursor.py
@@ -109,16 +109,17 @@ class TDengineCursor(object):
        if params is not None:
            pass
-        res = CTaosInterface.query(self._connection._conn, stmt)
+        self._result = CTaosInterface.query(self._connection._conn, stmt)
-        if res == 0:
+        errno = CTaosInterface.libtaos.taos_errno(self._result)
-            if CTaosInterface.fieldsCount(self._connection._conn) == 0:
+        if errno == 0:
-                self._affected_rows += CTaosInterface.affectedRows(self._connection._conn)
+            if CTaosInterface.fieldsCount(self._result) == 0:
-                return CTaosInterface.affectedRows(self._connection._conn)
+                self._affected_rows += CTaosInterface.affectedRows(self._result )
+                return CTaosInterface.affectedRows(self._result )
            else:
-                self._result, self._fields = CTaosInterface.useResult(self._connection._conn)
+                self._fields = CTaosInterface.useResult(self._result )
                return self._handle_result()
        else:
-            raise ProgrammingError(CTaosInterface.errStr(self._connection._conn))
+            raise ProgrammingError(CTaosInterface.errStr(self._result ))
    def executemany(self, operation, seq_of_parameters):
        """Prepare a database operation (query or command) and then execute it against all parameter sequences or mappings found in the sequence seq_of_parameters.

--- a/src/inc/taos.h
+++ b/src/inc/taos.h
@@ -88,14 +88,13 @@ int        taos_stmt_execute(TAOS_STMT *stmt);
 TAOS_RES * taos_stmt_use_result(TAOS_STMT *stmt);
 int        taos_stmt_close(TAOS_STMT *stmt);
-DLL_EXPORT int taos_query(TAOS *taos, const char *sql);
+DLL_EXPORT TAOS_RES *taos_query(TAOS *taos, const char *sql);
-DLL_EXPORT TAOS_RES *taos_use_result(TAOS *taos);
 DLL_EXPORT TAOS_ROW taos_fetch_row(TAOS_RES *res);
 DLL_EXPORT int taos_result_precision(TAOS_RES *res);  // get the time precision of result
 DLL_EXPORT void taos_free_result(TAOS_RES *res);
-DLL_EXPORT int taos_field_count(TAOS *taos);
+DLL_EXPORT int taos_field_count(TAOS_RES *tres);
 DLL_EXPORT int taos_num_fields(TAOS_RES *res);
-DLL_EXPORT int taos_affected_rows(TAOS *taos);
+DLL_EXPORT int taos_affected_rows(TAOS_RES *taos);
 DLL_EXPORT TAOS_FIELD *taos_fetch_fields(TAOS_RES *res);
 DLL_EXPORT int taos_select_db(TAOS *taos, const char *db);
 DLL_EXPORT int taos_print_row(char *str, TAOS_ROW row, TAOS_FIELD *fields, int num_fields);
@@ -112,9 +111,9 @@ int* taos_fetch_lengths(TAOS_RES *res);
 // TODO: the return value should be `const`
 DLL_EXPORT char *taos_get_server_info(TAOS *taos);
 DLL_EXPORT char *taos_get_client_info();
-DLL_EXPORT char *taos_errstr(TAOS *taos);
+DLL_EXPORT char *taos_errstr(TAOS_RES *tres);
-DLL_EXPORT int taos_errno(TAOS *taos);
+DLL_EXPORT int taos_errno(TAOS_RES *tres);
 DLL_EXPORT void taos_query_a(TAOS *taos, const char *sql, void (*fp)(void *param, TAOS_RES *, int code), void *param);
 DLL_EXPORT void taos_fetch_rows_a(TAOS_RES *res, void (*fp)(void *param, TAOS_RES *, int numOfRows), void *param);

--- a/src/inc/taosdef.h
+++ b/src/inc/taosdef.h
@@ -322,7 +322,7 @@ void tsDataSwap(void *pLeft, void *pRight, int32_t type, int32_t size);
 #define TSDB_QUERY_TYPE_SUBQUERY                       0x02u
 #define TSDB_QUERY_TYPE_STABLE_SUBQUERY                0x04u     // two-stage subquery for super table
-#define TSDB_QUERY_TYPE_TABLE_QUERY                    0x08u     // query ordinary table; below only apply to client side
+#define TSDB_QUERY_TYPE_TABLE_QUERY                    0x08u    // query ordinary table; below only apply to client side
 #define TSDB_QUERY_TYPE_STABLE_QUERY                   0x10u    // query on super table
 #define TSDB_QUERY_TYPE_JOIN_QUERY                     0x20u    // join query
 #define TSDB_QUERY_TYPE_PROJECTION_QUERY               0x40u    // select *,columns... query

--- a/src/inc/taoserror.h
+++ b/src/inc/taoserror.h
@@ -92,16 +92,15 @@ TAOS_DEFINE_ERROR(TSDB_CODE_NO_USER_FROM_CONN,          0, 0x0185, "can not get
 // table
 TAOS_DEFINE_ERROR(TSDB_CODE_TABLE_ALREADY_EXIST,        0, 0x0200, "table already exist")
 TAOS_DEFINE_ERROR(TSDB_CODE_INVALID_TABLE_ID,           0, 0x0201, "invalid table id")
-TAOS_DEFINE_ERROR(TSDB_CODE_INVALID_TABLE_TYPE,         0, 0x0202, "invalid table typee")
+TAOS_DEFINE_ERROR(TSDB_CODE_INVALID_TABLE_TYPE,         0, 0x0202, "invalid table type")
 TAOS_DEFINE_ERROR(TSDB_CODE_NOT_SUPER_TABLE,            0, 0x0203, "no super table")           // operation only available for super table
 TAOS_DEFINE_ERROR(TSDB_CODE_TAG_ALREAY_EXIST,           0, 0x0204, "tag already exist")
 TAOS_DEFINE_ERROR(TSDB_CODE_TAG_NOT_EXIST,              0, 0x0205, "tag not exist")
 TAOS_DEFINE_ERROR(TSDB_CODE_FIELD_ALREAY_EXIST,         0, 0x0206, "field already exist")
 TAOS_DEFINE_ERROR(TSDB_CODE_FIELD_NOT_EXIST,            0, 0x0207, "field not exist")
-TAOS_DEFINE_ERROR(TSDB_CODE_COL_NAME_TOO_LONG,          0, 0x0209, "column name too long")
+TAOS_DEFINE_ERROR(TSDB_CODE_COL_NAME_TOO_LONG,          0, 0x0208, "column name too long")
 TAOS_DEFINE_ERROR(TSDB_CODE_TOO_MANY_TAGS,              0, 0x0209, "too many tags")
 // dnode & mnode
 TAOS_DEFINE_ERROR(TSDB_CODE_NO_ENOUGH_DNODES,           0, 0x0280, "no enough dnodes")
 TAOS_DEFINE_ERROR(TSDB_CODE_DNODE_ALREADY_EXIST,        0, 0x0281, "dnode already exist")

--- a/src/kit/shell/src/shellEngine.c
+++ b/src/kit/shell/src/shellEngine.c
@@ -275,22 +275,28 @@ void shellRunCommandOnServer(TAOS *con, char command[]) {
  st = taosGetTimestampUs();
-  if (taos_query(con, command)) {
+  TAOS_RES* pSql = taos_query(con, command);
-    taos_error(con);
+  if (taos_errno(pSql)) {
+    taos_error(pSql);
    return;
  }
  if (regex_match(command, "^\\s*use\\s+[a-zA-Z0-9_]+\\s*;\\s*$", REG_EXTENDED | REG_ICASE)) {
    fprintf(stdout, "Database changed.\n\n");
    fflush(stdout);
+    taos_free_result(pSql);
    return;
  }
-  int num_fields = taos_field_count(con);
+  int num_fields = taos_field_count(pSql);
  if (num_fields != 0) {  // select and show kinds of commands
    int error_no = 0;
-    int numOfRows = shellDumpResult(con, fname, &error_no, printMode);
+    int numOfRows = shellDumpResult(pSql, fname, &error_no, printMode);
-    if (numOfRows < 0) return;
+    if (numOfRows < 0) {
+      taos_free_result(pSql);
+      return;
+    }
    et = taosGetTimestampUs();
    if (error_no == 0) {
@@ -299,7 +305,7 @@ void shellRunCommandOnServer(TAOS *con, char command[]) {
      printf("Query interrupted (%s), %d row(s) in set (%.6fs)\n", taos_errstr(con), numOfRows, (et - st) / 1E6);
    }
  } else {
-    int num_rows_affacted = taos_affected_rows(con);
+    int num_rows_affacted = taos_affected_rows(pSql);
    et = taosGetTimestampUs();
    printf("Query OK, %d row(s) affected (%.6fs)\n", num_rows_affacted, (et - st) / 1E6);
  }
@@ -309,6 +315,8 @@ void shellRunCommandOnServer(TAOS *con, char command[]) {
  if (fname != NULL) {
    wordfree(&full_path);
  }
+  taos_free_result(pSql);
 }
 /* Function to do regular expression check */
@@ -461,6 +469,7 @@ static int dumpResultToFile(const char* fname, TAOS_RES* result) {
  } while( row != NULL);
  fclose(fp);
+  taos_free_result(result);
  return numOfRows;
 }
@@ -548,15 +557,15 @@ static void printField(const char* val, TAOS_FIELD* field, int width, int32_t le
 }
-static int verticalPrintResult(TAOS_RES* result) {
+static int verticalPrintResult(TAOS_RES* tres) {
-  TAOS_ROW row = taos_fetch_row(result);
+  TAOS_ROW row = taos_fetch_row(tres);
  if (row == NULL) {
    return 0;
  }
-  int num_fields = taos_num_fields(result);
+  int num_fields = taos_num_fields(tres);
-  TAOS_FIELD *fields = taos_fetch_fields(result);
+  TAOS_FIELD *fields = taos_fetch_fields(tres);
-  int precision = taos_result_precision(result);
+  int precision = taos_result_precision(tres);
  int maxColNameLen = 0;
  for (int col = 0; col < num_fields; col++) {
@@ -569,7 +578,7 @@ static int verticalPrintResult(TAOS_RES* result) {
  int numOfRows = 0;
  do {
    printf("*************************** %d.row ***************************\n", numOfRows + 1);
-    int32_t* length = taos_fetch_lengths(result);
+    int32_t* length = taos_fetch_lengths(tres);
    for (int i = 0; i < num_fields; i++) {
      TAOS_FIELD* field = fields + i;
@@ -581,7 +590,7 @@ static int verticalPrintResult(TAOS_RES* result) {
    }
    numOfRows++;
-    row = taos_fetch_row(result);
+    row = taos_fetch_row(tres);
  } while(row != NULL);
  return numOfRows;
@@ -656,15 +665,15 @@ static void printHeader(TAOS_FIELD* fields, int* width, int num_fields) {
 }
-static int horizontalPrintResult(TAOS_RES* result) {
+static int horizontalPrintResult(TAOS_RES* tres) {
-  TAOS_ROW row = taos_fetch_row(result);
+  TAOS_ROW row = taos_fetch_row(tres);
  if (row == NULL) {
    return 0;
  }
-  int num_fields = taos_num_fields(result);
+  int num_fields = taos_num_fields(tres);
-  TAOS_FIELD *fields = taos_fetch_fields(result);
+  TAOS_FIELD *fields = taos_fetch_fields(tres);
-  int precision = taos_result_precision(result);
+  int precision = taos_result_precision(tres);
  int width[TSDB_MAX_COLUMNS];
  for (int col = 0; col < num_fields; col++) {
@@ -675,7 +684,7 @@ static int horizontalPrintResult(TAOS_RES* result) {
  int numOfRows = 0;
  do {
-    int32_t* length = taos_fetch_lengths(result);
+    int32_t* length = taos_fetch_lengths(tres);
    for (int i = 0; i < num_fields; i++) {
      putchar(' ');
      printField(row[i], fields + i, width[i], length[i], precision);
@@ -684,32 +693,24 @@ static int horizontalPrintResult(TAOS_RES* result) {
    }
    putchar('\n');
    numOfRows++;
-    row = taos_fetch_row(result);
+    row = taos_fetch_row(tres);
  } while(row != NULL);
  return numOfRows;
 }
-int shellDumpResult(TAOS *con, char *fname, int *error_no, bool vertical) {
+int shellDumpResult(TAOS_RES *tres, char *fname, int *error_no, bool vertical) {
  int numOfRows = 0;
-  TAOS_RES* result = taos_use_result(con);
-  if (result == NULL) {
-    taos_error(con);
-    return -1;
-  }
  if (fname != NULL) {
-    numOfRows = dumpResultToFile(fname, result);
+    numOfRows = dumpResultToFile(fname, tres);
  } else if(vertical) {
-    numOfRows = verticalPrintResult(result);
+    numOfRows = verticalPrintResult(tres);
  } else {
-    numOfRows = horizontalPrintResult(result);
+    numOfRows = horizontalPrintResult(tres);
  }
-  *error_no = taos_errno(con);
+  *error_no = taos_errno(tres);
-  taos_free_result(result);
  return numOfRows;
 }
@@ -771,12 +772,11 @@ void write_history() {
  fclose(f);
 }
-void taos_error(TAOS *con) {
+void taos_error(TAOS_RES *tres) {
-  fprintf(stderr, "\nDB error: %s\n", taos_errstr(con));
+  fprintf(stderr, "\nDB error: %s\n", taos_errstr(tres));
  /* free local resouce: allocated memory/metric-meta refcnt */
-  TAOS_RES *pRes = taos_use_result(con);
+  taos_free_result(tres);
-  taos_free_result(pRes);
 }
 int isCommentLine(char *line) {
@@ -858,8 +858,9 @@ void shellGetGrantInfo(void *con) {
  char sql[] = "show grants";
-  int code = taos_query(con, sql);
+  TAOS_RES* pSql = taos_query(con, sql);
+  int code = taos_errno(pSql);
  if (code != TSDB_CODE_SUCCESS) {
    if (code == TSDB_CODE_OPS_NOT_SUPPORT) {
      fprintf(stdout, "Server is Community Edition, version is %s\n\n", taos_get_server_info(con));
@@ -869,12 +870,11 @@ void shellGetGrantInfo(void *con) {
    return;
  }
-  int num_fields = taos_field_count(con);
+  int num_fields = taos_field_count(result);
  if (num_fields == 0) {
    fprintf(stderr, "\nInvalid grant information.\n");
    exit(0);
  } else {
-    result = taos_use_result(con);
    if (result == NULL) {
      fprintf(stderr, "\nGrant information is null.\n");
      exit(0);

--- a/src/kit/shell/src/shellImport.c
+++ b/src/kit/shell/src/shellImport.c
@@ -192,11 +192,14 @@ static void shellSourceFile(TAOS *con, char *fptr) {
    }
    memcpy(cmd + cmd_len, line, read_len);
-    if (taos_query(con, cmd)) {
+    TAOS_RES* pSql = taos_query(con, cmd);
+    int32_t code = taos_errno(pSql);
+    if (code != 0) {
      fprintf(stderr, "DB error: %s: %s (%d)\n", taos_errstr(con), fname, lineNo);
      /* free local resouce: allocated memory/metric-meta refcnt */
-      TAOS_RES *pRes = taos_use_result(con);
+      taos_free_result(pSql);
-      taos_free_result(pRes);
    }
    memset(cmd, 0, MAX_COMMAND_SIZE);

--- a/src/kit/shell/src/shellMain.c
+++ b/src/kit/shell/src/shellMain.c
@@ -18,21 +18,21 @@
 #include "tsclient.h"
 #include "tutil.h"
-TAOS*     con;
+TAOS_RES* con;
 pthread_t pid;
 // TODO: IMPLEMENT INTERRUPT HANDLER.
 void interruptHandler(int signum) {
 #ifdef LINUX
-  TAOS_RES* res = taos_use_result(con);
+  taos_stop_query(con);
-  taos_stop_query(res);
+  if (con != NULL) {
-  if (res != NULL) {
    /*
     * we need to free result in async model, in order to avoid free
     * results while the master thread is waiting for server response.
     */
-    tscQueueAsyncFreeResult(res);
+    tscQueueAsyncFreeResult(con);
  }
  result = NULL;
 #else
  printf("\nReceive ctrl+c or other signal, quit shell.\n");
@@ -90,7 +90,6 @@ int main(int argc, char* argv[]) {
  /* Initialize the shell */
  con = shellInit(&args);
  if (con == NULL) {
-    taos_error(con);
    exit(EXIT_FAILURE);
  }

--- a/src/kit/taosdemo/taosdemo.c
+++ b/src/kit/taosdemo/taosdemo.c
@@ -461,8 +461,7 @@ int main(int argc, char *argv[]) {
  taos_init();
  TAOS *taos = taos_connect(ip_addr, user, pass, NULL, port);
  if (taos == NULL) {
-    fprintf(stderr, "Failed to connect to TDengine, reason:%s\n", taos_errstr(taos));
+    fprintf(stderr, "Failed to connect to TDengine, reason:%s\n", taos_errstr(NULL));
-    taos_close(taos);
    return 1;
  }
  char command[BUFFER_SIZE] = "\0";
@@ -708,27 +707,24 @@ void *readTable(void *sarg) {
      sprintf(command, "select %s from %s%d where ts>= %" PRId64, aggreFunc[j], tb_prefix, i, sTime);
      double t = getCurrentTime();
-      if (taos_query(taos, command) != 0) {
+      TAOS_RES *pSql = taos_query(taos, command);
-        fprintf(stderr, "Failed to query\n");
+      int32_t code = taos_errno(pSql);
-        taos_close(taos);
-        exit(EXIT_FAILURE);
-      }
-      TAOS_RES *result = taos_use_result(taos);
+      if (code != 0) {
-      if (result == NULL) {
+        fprintf(stderr, "Failed to query:%s\n", taos_errstr(taos));
-        fprintf(stderr, "Failed to retreive results:%s\n", taos_errstr(taos));
+        taos_free_result(pSql);
        taos_close(taos);
-        exit(1);
+        exit(EXIT_FAILURE);
      }
-      while (taos_fetch_row(result) != NULL) {
+      while (taos_fetch_row(pSql) != NULL) {
        count++;
      }
      t = getCurrentTime() - t;
      totalT += t;
-      taos_free_result(result);
+      taos_free_result(pSql);
    }
    fprintf(fp, "|%10s  |   %10d   |  %12.2f   |   %10.2f  |\n",
@@ -779,20 +775,18 @@ void *readMetric(void *sarg) {
      fprintf(fp, "%s\n", command);
      double t = getCurrentTime();
-      if (taos_query(taos, command) != 0) {
-        fprintf(stderr, "Failed to query\n");
-        taos_close(taos);
-        exit(EXIT_FAILURE);
-      }
-      TAOS_RES *result = taos_use_result(taos);
+      TAOS_RES *pSql = taos_query(taos, command);
-      if (result == NULL) {
+      int32_t code = taos_errno(pSql);
-        fprintf(stderr, "Failed to retreive results:%s\n", taos_errstr(taos));
+      if (code != 0) {
+        fprintf(stderr, "Failed to query:%s\n", taos_errstr(taos));
+        taos_free_result(pSql);
        taos_close(taos);
        exit(1);
      }
      int count = 0;
-      while (taos_fetch_row(result) != NULL) {
+      while (taos_fetch_row(pSql) != NULL) {
        count++;
      }
      t = getCurrentTime() - t;
@@ -800,7 +794,7 @@ void *readMetric(void *sarg) {
      fprintf(fp, "| Speed: %12.2f(per s) | Latency: %.4f(ms) |\n", num_of_tables * num_of_DPT / t, t * 1000);
      printf("select %10s took %.6f second(s)\n\n", aggreFunc[j], t);
-      taos_free_result(result);
+      taos_free_result(pSql);
    }
    fprintf(fp, "\n");
  }
@@ -811,10 +805,19 @@ void *readMetric(void *sarg) {
 void queryDB(TAOS *taos, char *command) {
  int i = 5;
-  while (i > 0) {
+  TAOS_RES *pSql = NULL;
-    if (taos_query(taos, command) == 0) break;
+  int32_t code = -1;
+  while (i > 0 && code != 0) {
+    pSql = taos_query(taos, command);
+    code = taos_errno(pSql);
+    taos_free_result(pSql);
+    pSql = NULL;
+    if (code == 0) {
+      break;
+    }
    i--; 
  }
  if (i == 0) {
    fprintf(stderr, "Failed to run %s, reason: %s\n", command, taos_errstr(taos));
    taos_close(taos);
@@ -947,6 +950,7 @@ void callBack(void *param, TAOS_RES *res, int code) {
      break;
    }
  }
+   tb_info->timestamp = tmp_time;
  taos_query_a(tb_info->taos, buffer, callBack, tb_info);

--- a/src/kit/taosdump/taosdump.c
+++ b/src/kit/taosdump/taosdump.c
@@ -372,14 +372,12 @@ int taosGetTableRecordInfo(char *table, STableRecordInfo *pTableRecordInfo) {
  memset(pTableRecordInfo, 0, sizeof(STableRecordInfo));
  sprintf(command, "show tables like %s", table);
-  if (taos_query(taos, command) != 0) {
+  TAOS_RES *result = taos_query(taos, command);\
-    fprintf(stderr, "failed to run command %s\n", command);
+  int32_t code = taos_errno(result);
-    return -1;
-  }
-  result = taos_use_result(taos);
+  if (code != 0) {
-  if (result == NULL) {
+    fprintf(stderr, "failed to run command %s, error: %s\n", command, taos_errstr(result));
-    fprintf(stderr, "failed to use result\n");
+    taos_free_result(result);
    return -1;
  }
@@ -400,14 +398,12 @@ int taosGetTableRecordInfo(char *table, STableRecordInfo *pTableRecordInfo) {
  if (isSet) return 0;
  sprintf(command, "show stables like %s", table);
-  if (taos_query(taos, command) != 0) {
-    fprintf(stderr, "failed to run command %s\n", command);
-    return -1;
-  }
-  result = taos_use_result(taos);
+  result = taos_query(taos, command);
-  if (result == NULL) {
+  code = taos_errno(result);
-    fprintf(stderr, "failed to use result\n");
+  if (code != 0) {
+    fprintf(stderr, "failed to run command %s, error: %s\n", command, taos_errstr(result));
+    taos_free_result(result);
    return -1;
  }
@@ -467,14 +463,11 @@ int taosDumpOut(SDumpArguments *arguments) {
  taosDumpCharset(fp);
  sprintf(command, "show databases");
-  if (taos_query(taos, command) != 0) {
+  result = taos_query(taos, command);
+  int32_t code = taos_errno(result);
+  if (code != 0) {
    fprintf(stderr, "failed to run command: %s, reason: %s\n", command, taos_errstr(taos));
-    goto _exit_failure;
+    taos_free_result(result);
-  }
-  result = taos_use_result(taos);
-  if (result == NULL) {
-    fprintf(stderr, "failed to use result\n");
    goto _exit_failure;
  }
@@ -551,7 +544,7 @@ int taosDumpOut(SDumpArguments *arguments) {
      taosDumpCreateDbClause(dbInfos[0], arguments->with_property, fp);
      sprintf(command, "use %s", dbInfos[0]->name);
-      if (taos_query(taos, command) != 0) {
+      if (taos_query(taos, command) == NULL ) {
        fprintf(stderr, "invalid database %s\n", dbInfos[0]->name);
        goto _exit_failure;
      }
@@ -612,7 +605,7 @@ int taosDumpDb(SDbInfo *dbInfo, SDumpArguments *arguments, FILE *fp) {
  taosDumpCreateDbClause(dbInfo, arguments->with_property, fp);
  sprintf(command, "use %s", dbInfo->name);
-  if (taos_query(taos, command) != 0) {
+  if (taos_errno(taos_query(taos, command)) != 0) {
    fprintf(stderr, "invalid database %s\n", dbInfo->name);
    return -1;
  }
@@ -620,14 +613,11 @@ int taosDumpDb(SDbInfo *dbInfo, SDumpArguments *arguments, FILE *fp) {
  fprintf(fp, "USE %s\n\n", dbInfo->name);
  sprintf(command, "show tables");
-  if (taos_query(taos, command) != 0) {
+  result = taos_query(taos,command);
-    fprintf(stderr, "failed to run command %s\n", command);
+  int32_t code = taos_errno(result);
-    return -1;
+  if (code != 0) {
-  }
+    fprintf(stderr, "failed to run command %s, error: %s\n", command, taos_errstr(result));
+    taos_free_result(result);
-  result = taos_use_result(taos);
-  if (result == NULL) {
-    fprintf(stderr, "failed to use result\n");
    return -1;
  }
@@ -725,14 +715,11 @@ void taosDumpCreateMTableClause(STableDef *tableDes, char *metric, int numOfCols
    TAOS_ROW row = NULL;
    sprintf(command, "select %s from %s limit 1", tableDes->cols[counter].field, tableDes->name);
-    if (taos_query(taos, command) != 0) {
-      fprintf(stderr, "failed to run command %s\n", command);
-      return;
-    }
-    result = taos_use_result(taos);
+    result = taos_query(taos, command);
-    if (result == NULL) {
+    int32_t code = taos_errno(result);
-      fprintf(stderr, "failed to use result\n");
+    if (code != 0) {
+      fprintf(stderr, "failed to run command %s, error: %s\n", command, taos_errstr(result));
      return;
    }
@@ -806,14 +793,12 @@ int taosGetTableDes(char *table, STableDef *tableDes) {
  int count = 0;
  sprintf(command, "describe %s", table);
-  if (taos_query(taos, command) != 0) {
-    fprintf(stderr, "failed to run command %s\n", command);
-    return -1;
-  }
-  result = taos_use_result(taos);
+  result = taos_query(taos, command);
-  if (result == NULL) {
+  int32_t code = taos_errno(result);
-    fprintf(stderr, "failed to use result\n");
+  if (code != 0) {
+    fprintf(stderr, "failed to run command %s, error: %s\n", command, taos_errstr(result));
+    taos_free_result(result);
    return -1;
  }
@@ -889,14 +874,11 @@ int32_t taosDumpMetric(char *metric, SDumpArguments *arguments, FILE *fp) {
  strcpy(tableRecord.metric, metric);
  sprintf(command, "select tbname from %s", metric);
-  if (taos_query(taos, command) != 0) {
+  result = taos_query(taos, command);
-    fprintf(stderr, "failed to run command %s\n", command);
+  int32_t code = taos_errno(result);
-    return -1;
+  if (code != 0) {
-  }
+    fprintf(stderr, "failed to run command %s, error: %s\n", command, taos_errstr(result));
+    taos_free_result(result);
-  result = taos_use_result(taos);
-  if (result == NULL) {
-    fprintf(stderr, "failed to use result\n");
    return -1;
  }
@@ -942,18 +924,16 @@ int taosDumpTableData(FILE *fp, char *tbname, SDumpArguments *arguments) {
  sprintf(command, "select * from %s where _c0 >= %" PRId64 " and _c0 <= %" PRId64 " order by _c0 asc", tbname, arguments->start_time,
          arguments->end_time);
-  if (taos_query(taos, command) != 0) {
-    fprintf(stderr, "failed to run command %s, reason: %s\n", command, taos_errstr(taos));
+  result = taos_query(taos, command);
-    return -1;
+  int32_t code = taos_errno(result);
-  }
+  if (code != 0) {
+    fprintf(stderr, "failed to run command %s, reason: %s\n", command, taos_errstr(result));
-  result = taos_use_result(taos);
+    taos_free_result(result);
-  if (result == NULL) {
-    fprintf(stderr, "failed to use result\n");
    return -1;
  }
-  numFields = taos_field_count(taos);
+  numFields = taos_field_count(result);
  assert(numFields > 0);
  TAOS_FIELD *fields = taos_fetch_fields(result);
  tbuf = (char *)malloc(COMMAND_SIZE);
@@ -1194,7 +1174,7 @@ int taosDumpIn(SDumpArguments *arguments) {
          tcommand = command;
        }
        taosReplaceCtrlChar(tcommand);
-        if (taos_query(taos, tcommand) != 0)
+        if (taos_query(taos, tcommand) == NULL)
          fprintf(stderr, "linenu: %" PRId64 " failed to run command %s reason:%s \ncontinue...\n", linenu, command,
                  taos_errstr(taos));
@@ -1242,9 +1222,14 @@ int taosDumpIn(SDumpArguments *arguments) {
        tcommand = command;
      }
      taosReplaceCtrlChar(tcommand);
-      if (taos_query(taos, tcommand) != 0)
+      result = taos_query(taos, tcommand);
+      int32_t code = taos_errno(result);
+      if (code != 0) 
+      {
        fprintf(stderr, "linenu:%" PRId64 " failed to run command %s reason: %s \ncontinue...\n", linenu, command,
                taos_errstr(taos));
+      }
+      taos_free_result(result);
    }
    pstr = command;
@@ -1265,7 +1250,7 @@ int taosDumpIn(SDumpArguments *arguments) {
      tcommand = command;
    }
    taosReplaceCtrlChar(lcommand);
-    if (taos_query(taos, tcommand) != 0)
+    if (taos_query(taos, tcommand) == NULL)
      fprintf(stderr, "linenu:%" PRId64 " failed to run command %s reason:%s \ncontinue...\n", linenu, command,
              taos_errstr(taos));
  }

--- a/src/kit/taosnetwork/client.c
+++ b/src/kit/taosnetwork/client.c
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <arpa/inet.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#define BUFFER_SIZE 200
+typedef struct {
+  int   port;
+  char *host[15];
+} info;
+void *checkPort(void *sarg) {
+  info *pinfo = (info *)sarg;
+  int   port = pinfo->port;
+  char *host = *pinfo->host;
+  int   clientSocket;
+  struct sockaddr_in serverAddr;
+  char               sendbuf[BUFFER_SIZE];
+  char               recvbuf[BUFFER_SIZE];
+  int                iDataNum;
+  if ((clientSocket = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
+    perror("socket");
+    return NULL;
+  }
+  serverAddr.sin_family = AF_INET;
+  serverAddr.sin_port = htons(port);
+  serverAddr.sin_addr.s_addr = inet_addr(host);
+  printf("=================================\n");
+  if (connect(clientSocket, (struct sockaddr *)&serverAddr, sizeof(serverAddr)) < 0) {
+    perror("connect");
+    return NULL;
+  }
+  printf("Connect to: %s:%d...success\n", host, port);
+  sprintf(sendbuf, "send port_%d", port);
+  send(clientSocket, sendbuf, strlen(sendbuf), 0);
+  printf("Send msg_%d: %s\n", port, sendbuf);
+  recvbuf[0] = '\0';
+  iDataNum = recv(clientSocket, recvbuf, BUFFER_SIZE, 0);
+  recvbuf[iDataNum] = '\0';
+  printf("Read ack msg_%d: %s\n", port, recvbuf);
+  printf("=================================\n");
+  close(clientSocket);
+  return NULL;
+}
+void *checkUPort(void *sarg) {
+  info *pinfo = (info *)sarg;
+  int   port = pinfo->port;
+  char *host = *pinfo->host;
+  int   clientSocket;
+  struct sockaddr_in serverAddr;
+  char               sendbuf[BUFFER_SIZE];
+  char               recvbuf[BUFFER_SIZE];
+  int                iDataNum;
+  if ((clientSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
+    perror("socket");
+    return NULL;
+  }
+  serverAddr.sin_family = AF_INET;
+  serverAddr.sin_port = htons(port);
+  serverAddr.sin_addr.s_addr = inet_addr(host);
+  printf("=================================\n");
+  sprintf(sendbuf, "send msg port_%d by udp", port);
+  socklen_t sin_size = sizeof(*(struct sockaddr*)&serverAddr);
+  sendto(clientSocket, sendbuf, strlen(sendbuf), 0, (struct sockaddr *)&serverAddr, (int)sin_size);
+  printf("Send msg_%d by udp: %s\n", port, sendbuf);
+  recvbuf[0] = '\0';
+  iDataNum = recvfrom(clientSocket, recvbuf, BUFFER_SIZE, 0, (struct sockaddr *)&serverAddr, &sin_size);
+  recvbuf[iDataNum] = '\0';
+  printf("Read ack msg_%d from udp: %s\n", port, recvbuf);
+  printf("=================================\n");
+  close(clientSocket);
+  return NULL;
+}
+int main() {
+  int   port = 6020;
+  char *host = "127.0.0.1";
+  info *tinfo = malloc(sizeof(info));
+  info *uinfo = malloc(sizeof(info));
+  for (size_t i = 0; i < 30; i++) {
+    port++;
+    printf("For test: %s:%d\n", host, port);
+    *tinfo->host = host;
+    tinfo->port = port;
+    checkPort(tinfo);
+    *uinfo->host = host;
+    uinfo->port = port;
+    checkUPort(uinfo);
+  }
+  free(tinfo);
+  free(uinfo);
+}
\ No newline at end of file
--- a/src/kit/taosnetwork/server.c
+++ b/src/kit/taosnetwork/server.c
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <arpa/inet.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#define BUFFER_SIZE 200
+typedef struct {
+  int port;
+  int type;  // 0: tcp, 1: udo, default: 0
+} info;
+static void *bindPort(void *sarg) {
+  info *pinfo = (info *)sarg;
+  int   port = pinfo->port;
+  int   type = pinfo->type;
+  int   serverSocket;
+  struct sockaddr_in server_addr;
+  struct sockaddr_in clientAddr;
+  int                addr_len = sizeof(clientAddr);
+  int                client;
+  char               buffer[BUFFER_SIZE];
+  int                iDataNum;
+  if ((serverSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
+    perror("socket");
+    return NULL;
+  }
+  bzero(&server_addr, sizeof(server_addr));
+  server_addr.sin_family = AF_INET;
+  server_addr.sin_port = htons(port);
+  server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
+  if (bind(serverSocket, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
+    perror("connect");
+    return NULL;
+  }
+  if (listen(serverSocket, 5) < 0) {
+    perror("listen");
+    return NULL;
+  }
+  printf("Bind port: %d success\n", port);
+  while (1) {
+    client = accept(serverSocket, (struct sockaddr *)&clientAddr, (socklen_t *)&addr_len);
+    if (client < 0) {
+      perror("accept");
+      continue;
+    }
+    printf("=================================\n");
+    printf("Client ip is %s, Server port is %d\n", inet_ntoa(clientAddr.sin_addr), port);
+    while (1) {
+      buffer[0] = '\0';
+      iDataNum = recv(client, buffer, BUFFER_SIZE, 0);
+      if (iDataNum < 0) {
+        perror("recv null");
+        continue;
+      }
+      if (iDataNum > 0) {
+        buffer[iDataNum] = '\0';
+        printf("read msg:%s\n", buffer);
+        if (strcmp(buffer, "quit") == 0) break;
+        buffer[0] = '\0';
+        sprintf(buffer, "ack port_%d", port);
+        printf("send ack msg:%s\n", buffer);
+        send(client, buffer, strlen(buffer), 0);
+        break;
+      }
+    }
+    printf("=================================\n");
+  }
+  close(serverSocket);
+  return NULL;
+}
+static void *bindUPort(void *sarg) {
+  info *pinfo = (info *)sarg;
+  int   port = pinfo->port;
+  int   type = pinfo->type;
+  int   serverSocket;
+  struct sockaddr_in server_addr;
+  struct sockaddr_in clientAddr;
+  int                addr_len = sizeof(clientAddr);
+  int                client;
+  char               buffer[BUFFER_SIZE];
+  int                iDataNum;
+  if ((serverSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
+    perror("socket");
+    return NULL;
+  }
+  bzero(&server_addr, sizeof(server_addr));
+  server_addr.sin_family = AF_INET;
+  server_addr.sin_port = htons(port);
+  server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
+  if (bind(serverSocket, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
+    perror("connect");
+    return NULL;
+  }
+  socklen_t sin_size;
+  printf("Bind port: %d success\n", port);
+  while (1) {
+    buffer[0] = '\0';
+    sin_size = sizeof(*(struct sockaddr *)&server_addr);
+    iDataNum = recvfrom(serverSocket, buffer, BUFFER_SIZE, 0, (struct sockaddr *)&clientAddr, &sin_size);
+    if (iDataNum < 0) {
+      perror("recvfrom null");
+      continue;
+    }
+    if (iDataNum > 0) {
+      printf("=================================\n");
+      printf("Client ip is %s, Server port is %d\n", inet_ntoa(clientAddr.sin_addr), port);
+      buffer[iDataNum] = '\0';
+      printf("Read msg from udp:%s\n", buffer);
+      if (strcmp(buffer, "quit") == 0) break;
+      buffer[0] = '\0';
+      sprintf(buffer, "ack port_%d by udp", port);
+      printf("Send ack msg by udp:%s\n", buffer);
+      sendto(serverSocket, buffer, strlen(buffer), 0, (struct sockaddr *)&clientAddr, (int)sin_size);
+      send(client, buffer, strlen(buffer), 0);
+      printf("=================================\n");
+    }
+  }
+  close(serverSocket);
+  return NULL;
+}
+int main() {
+  int        port = 6020;
+  pthread_t *pids = malloc(60 * sizeof(pthread_t));
+  info *     infos = malloc(30 * sizeof(info));
+  info *     uinfos = malloc(30 * sizeof(info));
+  for (size_t i = 0; i < 30; i++) {
+    port++;
+    info *pinfo = infos++;
+    pinfo->port = port;
+    if (pthread_create(pids + i, NULL, bindPort, pinfo) != 0)  //创建线程
+    {                                                          //创建线程失败
+      printf("创建线程失败: %d.\n", port);
+      exit(0);
+    }
+    info *uinfo = uinfos++;
+    uinfo->port = port;
+    uinfo->type = 1;
+    if (pthread_create(pids + 30 + i, NULL, bindUPort, uinfo) != 0)  //创建线程
+    {                                                                //创建线程失败
+      printf("创建线程失败: %d.\n", port);
+      exit(0);
+    }
+  }
+  for (int i = 0; i < 30; i++) {
+    pthread_join(pids[i], NULL);
+    pthread_join(pids[(10 + i)], NULL);
+  }
+}
--- a/src/kit/taosnetwork/taosnetwork_client.c
+++ b/src/kit/taosnetwork/taosnetwork_client.c
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <netinet/in.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#define SERVER_PORT 8000
+#define SIZE 200
+int main() {
+  struct sockaddr_in servaddr, cliaddr;
+  socklen_t          cliaddr_len;
+  int                client_sockfd;
+  char               buf[SIZE];
+  char               recvbuf[SIZE];
+  int i, n, flag = 0;
+  int len, iDataNum;
+  client_sockfd = socket(AF_INET, SOCK_STREAM, 0);
+  bzero(&servaddr, sizeof(servaddr));
+  servaddr.sin_family = AF_INET;
+  servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
+  servaddr.sin_port = htons(SERVER_PORT);
+  if (connect(client_sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
+    printf("Connected error..\n");
+    return 0;
+  }
+  printf("Connected to server..\n");
+  /*循环的发送接收信息并打印接收信息（可以按需发送）--recv返回接收到的字节数，send返回发送的字节数*/
+  while (1) {
+    printf("Enter string to send:");
+    scanf("%s", buf);
+    if (!strcmp(buf, "quit")) {
+      break;
+    }
+    len = (sizeof buf);
+    recvbuf[0] = '\0';
+    iDataNum = recv(client_sockfd, recvbuf, SIZE, 0);
+    recvbuf[iDataNum] = '\0';
+    printf("%s\n", recvbuf);
+  }
+  return 0;
+}
--- a/src/kit/taosnetwork/taosnetwork_server.c
+++ b/src/kit/taosnetwork/taosnetwork_server.c
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <netinet/in.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#define SERVER_PORT 8000
+#define SIZE 200
+int main() {
+  struct sockaddr_in servaddr, cliaddr;
+  socklen_t          cliaddr_len;
+  int                listenfd, connfd;
+  char               buf[BUFSIZ];
+  int                i, n, flag = 0;
+  listenfd = socket(AF_INET, SOCK_STREAM, 0);
+  bzero(&servaddr, sizeof(servaddr));
+  servaddr.sin_family = AF_INET;
+  servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
+  servaddr.sin_port = htons(SERVER_PORT);
+  bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
+  listen(listenfd, 20);
+  printf("Accepting connections..\n");
+  while (1) {
+    cliaddr_len = sizeof(cliaddr);
+    connfd = accept(listenfd, (struct sockaddr *)&cliaddr,
+                    &cliaddr_len);  //如果得不到客户端发来的消息，将会被阻塞，一直等到消息到来
+    n = read(connfd, buf, SIZE);    //如果n<=0，表示客户端已断开
+    while (1) {
+      if (n != 0) {
+        for (i = 0; i < n; i++) printf("%c", buf[i]);  //输出客户端发来的信息
+      } else {
+        printf("Client say close the connection..\n");
+        break;
+      }
+      n = read(connfd, buf, SIZE);
+    }
+    close(connfd);
+  }
+}
--- a/src/kit/taosnetwork/test_client.c
+++ b/src/kit/taosnetwork/test_client.c
+#include <netinet/in.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#define SERVER_PORT 8888
+#define BUFF_LEN 512
+#define SERVER_IP "172.0.5.182"
+void udp_msg_sender(int fd, struct sockaddr* dst) {}
+/*
+    client:
+            socket-->sendto-->revcfrom-->close
+*/
+int main(int argc, char* argv[]) {
+  int                client_fd;
+  struct sockaddr_in ser_addr;
+  client_fd = socket(AF_INET, SOCK_DGRAM, 0);
+  if (client_fd < 0) {
+    printf("create socket fail!\n");
+    return -1;
+  }
+  memset(&ser_addr, 0, sizeof(ser_addr));
+  ser_addr.sin_family = AF_INET;
+  // ser_addr.sin_addr.s_addr = inet_addr(SERVER_IP);
+  ser_addr.sin_addr.s_addr = htonl(INADDR_ANY);  //注意网络序转换
+  ser_addr.sin_port = htons(SERVER_PORT);        //注意网络序转换
+  socklen_t          len;
+  struct sockaddr_in src;
+  while (1) {
+    char buf[BUFF_LEN] = "TEST UDP MSG!\n";
+    len = sizeof(*(struct sockaddr*)&ser_addr);
+    printf("client:%s\n", buf);  //打印自己发送的信息
+    sendto(client_fd, buf, BUFF_LEN, 0, (struct sockaddr*)&ser_addr, len);
+    memset(buf, 0, BUFF_LEN);
+    recvfrom(client_fd, buf, BUFF_LEN, 0, (struct sockaddr*)&src, &len);  //接收来自server的信息
+    printf("server:%s\n", buf);
+    sleep(1);  //一秒发送一次消息
+  }
+  close(client_fd);
+  return 0;
+}
\ No newline at end of file
--- a/src/kit/taosnetwork/test_server.c
+++ b/src/kit/taosnetwork/test_server.c
+#include <netinet/in.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#define SERVER_PORT 8888
+#define BUFF_LEN 1024
+void handle_udp_msg(int fd) {
+  char      buf[BUFF_LEN];  //接收缓冲区，1024字节
+  socklen_t len;
+  int       count;
+  struct sockaddr_in clent_addr;  // clent_addr用于记录发送方的地址信息
+  while (1) {
+    memset(buf, 0, BUFF_LEN);
+    len = sizeof(clent_addr);
+    count =
+        recvfrom(fd, buf, BUFF_LEN, 0, (struct sockaddr*)&clent_addr, &len);  // recvfrom是拥塞函数，没有数据就一直拥塞
+    if (count == -1) {
+      printf("recieve data fail!\n");
+      return;
+    }
+    printf("client:%s\n", buf);  //打印client发过来的信息
+    memset(buf, 0, BUFF_LEN);
+    sprintf(buf, "I have recieved %d bytes data!\n", count);  //回复client
+    printf("server:%s\n", buf);                               //打印自己发送的信息给
+    sendto(fd, buf, BUFF_LEN, 0, (struct sockaddr*)&clent_addr,
+           len);  //发送信息给client，注意使用了clent_addr结构体指针
+  }
+}
+/*
+    server:
+            socket-->bind-->recvfrom-->sendto-->close
+*/
+int main(int argc, char* argv[]) {
+  int                server_fd, ret;
+  struct sockaddr_in ser_addr;
+  server_fd = socket(AF_INET, SOCK_DGRAM, 0);  // AF_INET:IPV4;SOCK_DGRAM:UDP
+  if (server_fd < 0) {
+    printf("create socket fail!\n");
+    return -1;
+  }
+  memset(&ser_addr, 0, sizeof(ser_addr));
+  ser_addr.sin_family = AF_INET;
+  ser_addr.sin_addr.s_addr = htonl(INADDR_ANY);  // IP地址，需要进行网络序转换，INADDR_ANY：本地地址
+  ser_addr.sin_port = htons(SERVER_PORT);        //端口号，需要网络序转换
+  ret = bind(server_fd, (struct sockaddr*)&ser_addr, sizeof(ser_addr));
+  if (ret < 0) {
+    printf("socket bind fail!\n");
+    return -1;
+  }
+  handle_udp_msg(server_fd);  //处理接收到的数据
+  close(server_fd);
+  return 0;
+}
\ No newline at end of file
--- a/src/os/linux/src/linuxSysPara.c
+++ b/src/os/linux/src/linuxSysPara.c
@@ -245,10 +245,10 @@ static void taosGetSystemLocale() {  // get and set default locale
      strncpy(tsCharset, revisedCharset, tListLen(tsCharset));
      free(revisedCharset);
-      uError("charset not configured, set to system default:%s", tsCharset);
+      uWarn("charset not configured, set to system default:%s", tsCharset);
    } else {
      strcpy(tsCharset, "UTF-8");
-      uError("can't get locale and charset from system, set it to UTF-8");
+      uWarn("can't get locale and charset from system, set it to UTF-8");
    }
  }
 }

--- a/src/plugins/http/src/httpSql.c
+++ b/src/plugins/http/src/httpSql.c
@@ -58,10 +58,10 @@ void httpProcessMultiSqlRetrieveCallBack(void *param, TAOS_RES *result, int numO
    if (numOfRows < 0) {
      httpError("context:%p, fd:%d, ip:%s, user:%s, process pos:%d, retrieve failed code:%s, sql:%s",
                pContext, pContext->fd, pContext->ipstr, pContext->user, multiCmds->pos, tstrerror(numOfRows), sql);
-    } else {
+    } 
-      taos_free_result(result);
-    }
+    taos_free_result(result);
    if (singleCmd->cmdReturnType == HTTP_CMD_RETURN_TYPE_WITH_RETURN && encode->stopJsonFp) {
      (encode->stopJsonFp)(pContext, singleCmd);
    }
@@ -103,12 +103,15 @@ void httpProcessMultiSqlCallBack(void *param, TAOS_RES *result, int code) {
    }
    multiCmds->pos++;
    httpProcessMultiSql(pContext);
+    taos_free_result(result);
    return;
  }
-  if (result == NULL) {
+  int num_fields = taos_field_count(result);
+  if (num_fields == 0) {
    // not select or show commands
-    int affectRows = code;
+    int affectRows = taos_affected_rows(result);
    httpTrace("context:%p, fd:%d, ip:%s, user:%s, process pos:%d, affect rows:%d, sql:%s",
              pContext, pContext->fd, pContext->ipstr, pContext->user, multiCmds->pos, affectRows, sql);
@@ -132,6 +135,7 @@ void httpProcessMultiSqlCallBack(void *param, TAOS_RES *result, int code) {
      multiCmds->pos++;
    }
+    taos_free_result(result);
    httpProcessMultiSql(pContext);
  } else {
    httpTrace("context:%p, fd:%d, ip:%s, user:%s, process pos:%d, start retrieve, sql:%s",
@@ -212,9 +216,9 @@ void httpProcessSingleSqlRetrieveCallBack(void *param, TAOS_RES *result, int num
    if (numOfRows < 0) {
      httpError("context:%p, fd:%d, ip:%s, user:%s, retrieve failed, code:%s", pContext, pContext->fd, pContext->ipstr,
                pContext->user, tstrerror(numOfRows));
-    } else {
+    } 
-      taos_free_result(result);
-    }
+    taos_free_result(result);    
    if (encode->stopJsonFp) {
      (encode->stopJsonFp)(pContext, &pContext->singleCmd);
@@ -247,12 +251,14 @@ void httpProcessSingleSqlCallBack(void *param, TAOS_RES *result, int code) {
                pContext, pContext->fd, pContext->ipstr, pContext->user, pContext->session->taos, tstrerror(code), pObj);
      httpSendTaosdErrorResp(pContext, code);
    }
+    taos_free_result(result);
    return;
  }
-  if (result == NULL) {
+  int num_fields = taos_field_count(result);
+  if (num_fields == 0) {
    // not select or show commands
-    int affectRows = code;
+    int affectRows = taos_affected_rows(result);
    httpTrace("context:%p, fd:%d, ip:%s, user:%s, affect rows:%d, stop query, sqlObj:%p",
              pContext, pContext->fd, pContext->ipstr, pContext->user, affectRows, result);
@@ -269,6 +275,7 @@ void httpProcessSingleSqlCallBack(void *param, TAOS_RES *result, int code) {
      (encode->stopJsonFp)(pContext, &pContext->singleCmd);
    }
+    taos_free_result(result);
    httpCloseContextByApp(pContext);
  } else {
    httpTrace("context:%p, fd:%d, ip:%s, user:%s, start retrieve", pContext, pContext->fd, pContext->ipstr,

--- a/src/query/inc/qExecutor.h
+++ b/src/query/inc/qExecutor.h
@@ -116,11 +116,14 @@ typedef struct SQueryCostInfo {
  uint64_t loadDataInCacheSize;
  uint64_t loadDataTime;
-  uint64_t dataInRows;
+  uint64_t totalRows;
-  uint64_t checkRows;
+  uint64_t totalCheckedRows;
-  uint32_t dataBlocks;
+  uint32_t totalBlocks;
+  uint32_t loadBlocks;
  uint32_t loadBlockStatis;
  uint32_t discardBlocks;
+  uint64_t elapsedTime;
+  uint64_t computTime;
 } SQueryCostInfo;
 typedef struct SGroupItem {
@@ -168,7 +171,7 @@ typedef struct SQueryRuntimeEnv {
  SWindowResInfo       windowResInfo;
  STSBuf*              pTSBuf;
  STSCursor            cur;
-  SQueryCostInfo    summary;
+  SQueryCostInfo       summary;
  bool                 stableQuery;  // super table query or not
  void*                pQueryHandle;
  void*                pSecQueryHandle;  // another thread for
@@ -177,8 +180,6 @@ typedef struct SQueryRuntimeEnv {
 typedef struct SQInfo {
  void*   signature;
-  TSKEY   startTime;
-  TSKEY   elapsedTime;
  int32_t pointsInterpo;
  int32_t code;  // error code to returned to client
  sem_t   dataReady;

--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -1183,6 +1183,7 @@ static int32_t tableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, SDataBl
  STableQueryInfo* pTableQInfo = pQuery->current;
  SWindowResInfo*  pWindowResInfo = &pRuntimeEnv->windowResInfo;
+  pQuery->pos = QUERY_IS_ASC_QUERY(pQuery)? 0 : pDataBlockInfo->rows - 1;
  if (pQuery->numOfFilterCols > 0 || pRuntimeEnv->pTSBuf != NULL || isGroupbyNormalCol(pQuery->pGroupbyExpr)) {
    rowwiseApplyFunctions(pRuntimeEnv, pStatis, pDataBlockInfo, pWindowResInfo, pDataBlock);
@@ -1190,10 +1191,10 @@ static int32_t tableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, SDataBl
    blockwiseApplyFunctions(pRuntimeEnv, pStatis, pDataBlockInfo, pWindowResInfo, searchFn, pDataBlock);
  }
+  // update the lastkey of current table
  TSKEY lastKey = QUERY_IS_ASC_QUERY(pQuery) ? pDataBlockInfo->window.ekey : pDataBlockInfo->window.skey;
  pTableQInfo->lastKey = lastKey + GET_FORWARD_DIRECTION_FACTOR(pQuery->order.order);
  // interval query with limit applied
  int32_t numOfRes = 0;
@@ -2013,7 +2014,7 @@ SArray *loadDataBlockOnDemand(SQueryRuntimeEnv *pRuntimeEnv, void* pQueryHandle,
    if (*pStatis == NULL) { // data block statistics does not exist, load data block
      pDataBlock = tsdbRetrieveDataBlock(pQueryHandle, NULL);
-      pRuntimeEnv->summary.checkRows += pBlockInfo->rows;
+      pRuntimeEnv->summary.totalCheckedRows += pBlockInfo->rows;
    }
  } else {
    assert(r == BLK_DATA_ALL_NEEDED);
@@ -2032,7 +2033,7 @@ SArray *loadDataBlockOnDemand(SQueryRuntimeEnv *pRuntimeEnv, void* pQueryHandle,
      //        return DISK_DATA_DISCARDED;
    }
-    pRuntimeEnv->summary.checkRows += pBlockInfo->rows;
+    pRuntimeEnv->summary.totalCheckedRows += pBlockInfo->rows;
    pDataBlock = tsdbRetrieveDataBlock(pQueryHandle, NULL);
  }
@@ -2149,7 +2150,7 @@ static int64_t doScanAllDataBlocks(SQueryRuntimeEnv *pRuntimeEnv) {
  TsdbQueryHandleT pQueryHandle = IS_MASTER_SCAN(pRuntimeEnv)? pRuntimeEnv->pQueryHandle : pRuntimeEnv->pSecQueryHandle;
  while (tsdbNextDataBlock(pQueryHandle)) {
-    pRuntimeEnv->summary.dataBlocks += 1;
+    pRuntimeEnv->summary.totalBlocks += 1;
    if (isQueryKilled(GET_QINFO_ADDR(pRuntimeEnv))) {
      return 0;
    }
@@ -2185,12 +2186,10 @@ static int64_t doScanAllDataBlocks(SQueryRuntimeEnv *pRuntimeEnv) {
    ensureOutputBuffer(pRuntimeEnv, &blockInfo);
    SDataStatis *pStatis = NULL;
-    pQuery->pos = QUERY_IS_ASC_QUERY(pQuery)? 0 : blockInfo.rows - 1;
    SArray *pDataBlock = loadDataBlockOnDemand(pRuntimeEnv, pQueryHandle, &blockInfo, &pStatis);
    int32_t numOfRes = tableApplyFunctionsOnBlock(pRuntimeEnv, &blockInfo, pStatis, binarySearchForKey, pDataBlock);
-    pRuntimeEnv->summary.dataInRows += blockInfo.rows;
+    pRuntimeEnv->summary.totalRows += blockInfo.rows;
    qTrace("QInfo:%p check data block, brange:%" PRId64 "-%" PRId64 ", numOfRows:%d, numOfRes:%d, lastKey:%"PRId64, GET_QINFO_ADDR(pRuntimeEnv),
           blockInfo.window.skey, blockInfo.window.ekey, blockInfo.rows, numOfRes, pQuery->current->lastKey);
@@ -3253,7 +3252,7 @@ void destroyTableQueryInfo(STableQueryInfo *pTableQueryInfo, int32_t numOfCols)
  free(pTableQueryInfo);
 }
-void restoreIntervalQueryRange(SQueryRuntimeEnv *pRuntimeEnv, STableQueryInfo *pTableQueryInfo) {
+void setCurrentQueryTable(SQueryRuntimeEnv *pRuntimeEnv, STableQueryInfo *pTableQueryInfo) {
  SQuery *pQuery = pRuntimeEnv->pQuery;
  pQuery->current = pTableQueryInfo;
@@ -3322,7 +3321,7 @@ static void setWindowResOutputBuf(SQueryRuntimeEnv *pRuntimeEnv, SWindowResult *
 int32_t setAdditionalInfo(SQInfo *pQInfo, STableId* pTableId, STableQueryInfo *pTableQueryInfo) {
  SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
-  assert(pTableQueryInfo->lastKey >= 0);
+  assert(pTableQueryInfo->lastKey >= TSKEY_INITIAL_VAL);
  setTagVal(pRuntimeEnv, pTableId, pQInfo->tsdb);
@@ -3534,10 +3533,11 @@ static void updateWindowResNumOfRes(SQueryRuntimeEnv *pRuntimeEnv, STableQueryIn
  }
 }
-void stableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, STableQueryInfo *pTableQueryInfo,
+void stableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, SDataBlockInfo *pDataBlockInfo, SDataStatis *pStatis,
-                                 SDataBlockInfo *pDataBlockInfo, SDataStatis *pStatis, SArray *pDataBlock,
+    SArray *pDataBlock, __block_search_fn_t searchFn) {
-                                 __block_search_fn_t searchFn) {
  SQuery *         pQuery = pRuntimeEnv->pQuery;
+  STableQueryInfo* pTableQueryInfo = pQuery->current;
  SWindowResInfo * pWindowResInfo = &pTableQueryInfo->windowResInfo;
  pQuery->pos = QUERY_IS_ASC_QUERY(pQuery)? 0 : pDataBlockInfo->rows - 1;
@@ -3670,10 +3670,8 @@ int32_t doFillGapsInResults(SQueryRuntimeEnv* pRuntimeEnv, tFilePage **pDst, int
  }
 }
-void queryCostStatis(SQInfo *pQInfo) {
+static void queryCostStatis(SQInfo *pQInfo) {
  SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
-//  SQuery *pQuery = pRuntimeEnv->pQuery;
  SQueryCostInfo *pSummary = &pRuntimeEnv->summary;
 //  if (pRuntimeEnv->pResultBuf == NULL) {
 ////    pSummary->tmpBufferInDisk = 0;
@@ -3693,8 +3691,9 @@ void queryCostStatis(SQInfo *pQInfo) {
 //      pQInfo, pSummary->readDiskBlocks, pSummary->totalBlockSize, pSummary->loadBlocksUs / 1000.0,
 //      pSummary->skippedFileBlocks, pSummary->totalGenData);
-  qTrace("QInfo:%p cost: check blocks:%d, statis:%d, rows:%"PRId64", check rows:%"PRId64, pQInfo, pSummary->dataBlocks,
+  qTrace("QInfo:%p :cost summary: elpased time:%"PRId64" us, total blocks:%d, use block statis:%d, use block data:%d, "
-         pSummary->loadBlockStatis, pSummary->dataInRows, pSummary->checkRows);
+         "total rows:%"PRId64 ", check rows:%"PRId64, pQInfo, pSummary->elapsedTime, pSummary->totalBlocks,
+         pSummary->loadBlockStatis, pSummary->loadBlocks, pSummary->totalRows, pSummary->totalCheckedRows);
 //  qTrace("QInfo:%p cost: temp file:%d Bytes", pQInfo, pSummary->tmpBufferInDisk);
 //
@@ -4090,12 +4089,13 @@ static void enableExecutionForNextTable(SQueryRuntimeEnv *pRuntimeEnv) {
 static int64_t queryOnDataBlocks(SQInfo *pQInfo) {
  SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
  SQuery *          pQuery = pRuntimeEnv->pQuery;
+  SQueryCostInfo* summary  = &pRuntimeEnv->summary;
  int64_t st = taosGetTimestampMs();
  TsdbQueryHandleT pQueryHandle = IS_MASTER_SCAN(pRuntimeEnv)? pRuntimeEnv->pQueryHandle : pRuntimeEnv->pSecQueryHandle;
  while (tsdbNextDataBlock(pQueryHandle)) {
+    summary->totalBlocks += 1;
    if (isQueryKilled(pQInfo)) {
      break;
    }
@@ -4127,10 +4127,9 @@ static int64_t queryOnDataBlocks(SQInfo *pQInfo) {
    }
    assert(pTableQueryInfo != NULL);
-    restoreIntervalQueryRange(pRuntimeEnv, pTableQueryInfo);
+    setCurrentQueryTable(pRuntimeEnv, pTableQueryInfo);
    SDataStatis *pStatis = NULL;
    SArray *pDataBlock = loadDataBlockOnDemand(pRuntimeEnv, pQueryHandle, &blockInfo, &pStatis);
    if (!isIntervalQuery(pQuery)) {
@@ -4139,15 +4138,14 @@ static int64_t queryOnDataBlocks(SQInfo *pQInfo) {
    } else {  // interval query
      TSKEY nextKey = blockInfo.window.skey;
      setIntervalQueryRange(pQInfo, nextKey);
-      int32_t ret = setAdditionalInfo(pQInfo, &pTableQueryInfo->id, pTableQueryInfo);
+      /*int32_t ret = */setAdditionalInfo(pQInfo, &pTableQueryInfo->id, pTableQueryInfo);
-      if (ret != TSDB_CODE_SUCCESS) {
-        pQInfo->code = ret;
-        return taosGetTimestampMs() - st;
-      }
    }
-    stableApplyFunctionsOnBlock(pRuntimeEnv, pTableQueryInfo, &blockInfo, pStatis, pDataBlock, binarySearchForKey);
+    summary->totalRows += blockInfo.rows;
+    stableApplyFunctionsOnBlock(pRuntimeEnv, &blockInfo, pStatis, pDataBlock, binarySearchForKey);
+    qTrace("QInfo:%p check data block, brange:%" PRId64 "-%" PRId64 ", numOfRows:%d, lastKey:%"PRId64, GET_QINFO_ADDR(pRuntimeEnv),
+           blockInfo.window.skey, blockInfo.window.ekey, blockInfo.rows, pQuery->current->lastKey);
  }
  int64_t et = taosGetTimestampMs();
@@ -4509,10 +4507,6 @@ static void multiTableQueryProcess(SQInfo *pQInfo) {
      copyFromWindowResToSData(pQInfo, pRuntimeEnv->windowResInfo.pResult);
    }
-    if (pQuery->rec.rows == 0) {
-      //      queryCostStatis(pSupporter);
-    }
    qTrace("QInfo:%p current:%lld, total:%lld", pQInfo, pQuery->rec.rows, pQuery->rec.total);
    return;
  }
@@ -4795,7 +4789,6 @@ static void tableQueryImpl(SQInfo *pQInfo) {
    }
    qTrace("QInfo:%p query over, %d rows are returned", pQInfo, pQuery->rec.total);
-    queryCostStatis(pQInfo);
    return;
  }
@@ -4818,7 +4811,7 @@ static void tableQueryImpl(SQInfo *pQInfo) {
  }
  // record the total elapsed time
-  pQInfo->elapsedTime += (taosGetTimestampUs() - st);
+  pRuntimeEnv->summary.elapsedTime += (taosGetTimestampUs() - st);
  assert(pQInfo->groupInfo.numOfTables == 1);
  /* check if query is killed or not */
@@ -4827,10 +4820,6 @@ static void tableQueryImpl(SQInfo *pQInfo) {
  } else {// todo set the table uid and tid in log
    qTrace("QInfo:%p query paused, %" PRId64 " rows returned, numOfTotal:%" PRId64 " rows",
        pQInfo, pQuery->rec.rows, pQuery->rec.total + pQuery->rec.rows);
-    if (Q_STATUS_EQUAL(pQuery->status, QUERY_COMPLETED)) {
-      queryCostStatis(pQInfo);
-    }
  }
 }
@@ -4852,13 +4841,10 @@ static void stableQueryImpl(SQInfo *pQInfo) {
  }
  // record the total elapsed time
-  pQInfo->elapsedTime += (taosGetTimestampUs() - st);
+  pQInfo->runtimeEnv.summary.elapsedTime += (taosGetTimestampUs() - st);
-  //  taosFillSetStartInfo(&pQInfo->runtimeEnv.pFillInfo, pQuery->size, pQInfo->query.fillType);
  if (pQuery->rec.rows == 0) {
-    qTrace("QInfo:%p over, %d tables queried, %d points are returned", pQInfo, pQInfo->groupInfo.numOfTables,
+    qTrace("QInfo:%p over, %d tables queried, %d rows are returned", pQInfo, pQInfo->groupInfo.numOfTables, pQuery->rec.total);
-           pQuery->rec.total);
-    //    queryCostStatis(pSupporter);
  }
 }
@@ -5838,9 +5824,11 @@ int32_t qCreateQueryInfo(void *tsdb, int32_t vgId, SQueryTableMsg *pQueryMsg, qi
        numOfGroupByCols = 0;
      }
-      // todo handle the error
+      code = tsdbQuerySTableByTagCond(tsdb, id->uid, tagCond, pQueryMsg->tagCondLen, pQueryMsg->tagNameRelType, tbnameCond, &groupInfo, pGroupColIndex,
-      /*int32_t ret =*/tsdbQuerySTableByTagCond(tsdb, id->uid, tagCond, pQueryMsg->tagCondLen, pQueryMsg->tagNameRelType, tbnameCond, &groupInfo, pGroupColIndex,
                                          numOfGroupByCols);
+      if (code != TSDB_CODE_SUCCESS) {
+        goto _over;
+      }
    } else {
      SArray* pTableGroup = taosArrayInit(1, POINTER_BYTES);
@@ -5870,7 +5858,7 @@ _over:
  taosArrayDestroy(pTableIdList);
  if (code != TSDB_CODE_SUCCESS) {
-    //pQInfo already freed in initQinfo 
+    //pQInfo already freed in initQInfo, but *pQInfo may not pointer to null; 
    *pQInfo = NULL;
  }
@@ -5880,6 +5868,9 @@ _over:
 void qDestroyQueryInfo(qinfo_t pQInfo) {
  qTrace("QInfo:%p query completed", pQInfo);
+  // print the query cost summary
+  queryCostStatis(pQInfo);
  freeQInfo(pQInfo);
 }
@@ -5956,6 +5947,7 @@ int32_t qDumpRetrieveResult(qinfo_t qinfo, SRetrieveTableRsp **pRsp, int32_t *co
    return TSDB_CODE_INVALID_QHANDLE;
  }
+  SQueryRuntimeEnv* pRuntimeEnv = &pQInfo->runtimeEnv;
  SQuery *pQuery = pQInfo->runtimeEnv.pQuery;
  size_t  size = getResultSize(pQInfo, &pQuery->rec.rows);
  size += sizeof(int32_t);
@@ -5969,7 +5961,7 @@ int32_t qDumpRetrieveResult(qinfo_t qinfo, SRetrieveTableRsp **pRsp, int32_t *co
  int32_t code = pQInfo->code;
  if (code == TSDB_CODE_SUCCESS) {
    (*pRsp)->offset = htobe64(pQuery->limit.offset);
-    (*pRsp)->useconds = htobe64(pQInfo->elapsedTime);
+    (*pRsp)->useconds = htobe64(pRuntimeEnv->summary.elapsedTime);
  } else {
    (*pRsp)->offset = 0;
    (*pRsp)->useconds = 0;

--- a/src/query/src/qfill.c
+++ b/src/query/src/qfill.c
@@ -110,6 +110,14 @@ void taosDestoryFillInfo(SFillInfo* pFillInfo) {
  tfree(pFillInfo->prevValues);
  tfree(pFillInfo->nextValues);
  tfree(pFillInfo->pTags);
+  for(int32_t i = 0; i < pFillInfo->numOfCols; ++i) {
+    tfree(pFillInfo->pData[i]);
+  }
+  tfree(pFillInfo->pData);
+  tfree(pFillInfo->pFillCol);
  tfree(pFillInfo);
 }
@@ -247,7 +255,7 @@ int taosDoLinearInterpolation(int32_t type, SPoint* point1, SPoint* point2, SPoi
 }
 static void setTagsValue(SFillInfo* pColInfo, tFilePage** data, char** pTags, int32_t start, int32_t num) {
-  for (int32_t j = 0, i = start; i < pColInfo->numOfCols + pColInfo->numOfTags; ++i, ++j) {
+  for (int32_t j = 0, i = start; i < pColInfo->numOfCols; ++i, ++j) {
    SFillColInfo* pCol = &pColInfo->pFillCol[i];
    char* val1 = elePtrAt(data[i]->data, pCol->col.bytes, num);
@@ -344,7 +352,7 @@ static void doInterpoResultImpl(SFillInfo* pFillInfo, tFilePage** data, int32_t*
      setTagsValue(pFillInfo, data, pTags, numOfValCols, *num);
    }
-  } else { /* default value interpolation */
+  } else { /* fill the default value */
    for (int32_t i = 1; i < numOfValCols; ++i) {
      SFillColInfo* pCol = &pFillInfo->pFillCol[i];

--- a/src/tsdb/src/tsdbRead.c
+++ b/src/tsdb/src/tsdbRead.c
@@ -193,7 +193,7 @@ TsdbQueryHandleT* tsdbQueryTables(TsdbRepoT* tsdb, STsdbQueryCond* pCond, STable
    }
  }
-  uTrace("%p total numOfTable:%d in query", pQueryHandle, taosArrayGetSize(pQueryHandle->pTableCheckInfo));
+  tsdbTrace("%p total numOfTable:%d in query", pQueryHandle, taosArrayGetSize(pQueryHandle->pTableCheckInfo));
  tsdbInitDataBlockLoadInfo(&pQueryHandle->dataBlockLoadInfo);
  tsdbInitCompBlockLoadInfo(&pQueryHandle->compBlockLoadInfo);
@@ -282,10 +282,10 @@ static bool initTableMemIterator(STsdbQueryHandle* pHandle, STableCheckInfo* pCh
    SDataRow row = SL_GET_NODE_DATA(node);
    TSKEY key = dataRowKey(row);  // first timestamp in buffer
-    uTrace("%p uid:%" PRId64", tid:%d check data in mem from skey:%" PRId64 ", order:%d, %p", pHandle,
+    tsdbTrace("%p uid:%" PRId64", tid:%d check data in mem from skey:%" PRId64 ", order:%d, %p", pHandle,
           pCheckInfo->tableId.uid, pCheckInfo->tableId.tid, key, order, pHandle->qinfo);
  } else {
-    uTrace("%p uid:%" PRId64 ", tid:%d no data in mem", pHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid);
+    tsdbTrace("%p uid:%" PRId64 ", tid:%d no data in mem", pHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid);
  }
  if (!imemEmpty) {
@@ -294,10 +294,10 @@ static bool initTableMemIterator(STsdbQueryHandle* pHandle, STableCheckInfo* pCh
    SDataRow row = SL_GET_NODE_DATA(node);
    TSKEY key = dataRowKey(row);  // first timestamp in buffer
-    uTrace("%p uid:%" PRId64", tid:%d check data in imem from skey:%" PRId64 ", order:%d, %p", pHandle,
+    tsdbTrace("%p uid:%" PRId64", tid:%d check data in imem from skey:%" PRId64 ", order:%d, %p", pHandle,
           pCheckInfo->tableId.uid, pCheckInfo->tableId.tid, key, order, pHandle->qinfo);
  } else {
-    uTrace("%p uid:%"PRId64", tid:%d no data in imem", pHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid);
+    tsdbTrace("%p uid:%"PRId64", tid:%d no data in imem", pHandle, pCheckInfo->tableId.uid, pCheckInfo->tableId.tid);
  }
  return true;
@@ -338,7 +338,7 @@ static bool hasMoreDataInCache(STsdbQueryHandle* pHandle) {
  SDataRow row = SL_GET_NODE_DATA(node);
  pCheckInfo->lastKey = dataRowKey(row);  // first timestamp in buffer
-  uTrace("%p uid:%" PRId64", tid:%d check data in buffer from skey:%" PRId64 ", order:%d, %p", pHandle,
+  tsdbTrace("%p uid:%" PRId64", tid:%d check data in buffer from skey:%" PRId64 ", order:%d, %p", pHandle,
      pCheckInfo->tableId.uid, pCheckInfo->tableId.tid, pCheckInfo->lastKey, pHandle->order, pHandle->qinfo);
  // all data in mem are checked already.
@@ -1038,7 +1038,7 @@ static void doMergeTwoLevelData(STsdbQueryHandle* pQueryHandle, STableCheckInfo*
  cur->rows = numOfRows;
  cur->pos = pos;
-  uTrace("%p uid:%" PRIu64",tid:%d data block created, brange:%"PRIu64"-%"PRIu64" %p", pQueryHandle, cur->win.skey,
+  tsdbTrace("%p uid:%" PRIu64",tid:%d data block created, brange:%"PRIu64"-%"PRIu64" %p", pQueryHandle, cur->win.skey,
      cur->win.ekey, cur->rows, pQueryHandle->qinfo);
 }
@@ -1138,7 +1138,7 @@ static int32_t dataBlockOrderCompar(const void* pLeft, const void* pRight, void*
  if (pLeftBlockInfoEx->compBlock->offset == pRightBlockInfoEx->compBlock->offset &&
      pLeftBlockInfoEx->compBlock->last == pRightBlockInfoEx->compBlock->last) {
    // todo add more information
-    uError("error in header file, two block with same offset:%p", pLeftBlockInfoEx->compBlock->offset);
+    tsdbError("error in header file, two block with same offset:%p", pLeftBlockInfoEx->compBlock->offset);
  }
  return pLeftBlockInfoEx->compBlock->offset > pRightBlockInfoEx->compBlock->offset ? 1 : -1;
@@ -1200,7 +1200,7 @@ static int32_t createDataBlocksInfo(STsdbQueryHandle* pQueryHandle, int32_t numO
    numOfQualTables++;
  }
-  uTrace("%p create data blocks info struct completed, %d blocks in %d tables", pQueryHandle, cnt, numOfQualTables);
+  tsdbTrace("%p create data blocks info struct completed, %d blocks in %d tables", pQueryHandle, cnt, numOfQualTables);
  assert(cnt <= numOfBlocks && numOfQualTables <= numOfTables);  // the pTableQueryInfo[j]->numOfBlocks may be 0
  sup.numOfTables = numOfQualTables;
@@ -1236,7 +1236,7 @@ static int32_t createDataBlocksInfo(STsdbQueryHandle* pQueryHandle, int32_t numO
   * }
   */
-  uTrace("%p %d data blocks sort completed", pQueryHandle, cnt);
+  tsdbTrace("%p %d data blocks sort completed", pQueryHandle, cnt);
  cleanBlockOrderSupporter(&sup, numOfTables);
  free(pTree);
@@ -1257,7 +1257,7 @@ static bool getDataBlocksInFilesImpl(STsdbQueryHandle* pQueryHandle) {
      break;
    }
-    uTrace("%p %d blocks found in file for %d table(s), fid:%d", pQueryHandle, numOfBlocks,
+    tsdbTrace("%p %d blocks found in file for %d table(s), fid:%d", pQueryHandle, numOfBlocks,
           numOfTables, pQueryHandle->pFileGroup->fileId);
    assert(numOfBlocks >= 0);
@@ -1583,7 +1583,7 @@ static int tsdbReadRowsFromCache(SSkipListIterator* pIter, STable* pTable, TSKEY
    if ((key > maxKey && ASCENDING_TRAVERSE(pQueryHandle->order)) ||
        (key < maxKey && !ASCENDING_TRAVERSE(pQueryHandle->order))) {
-      uTrace("%p key:%"PRIu64" beyond qrange:%"PRId64" - %"PRId64", no more data in buffer", pQueryHandle, key, pQueryHandle->window.skey,
+      tsdbTrace("%p key:%"PRIu64" beyond qrange:%"PRId64" - %"PRId64", no more data in buffer", pQueryHandle, key, pQueryHandle->window.skey,
          pQueryHandle->window.ekey);
      break;
@@ -1958,7 +1958,7 @@ SArray* createTableGroup(SArray* pTableList, STSchema* pTagSchema, SColIndex* pC
  size_t size = taosArrayGetSize(pTableList);
  if (size == 0) {
-    uTrace("no qualified tables");
+    tsdbTrace("no qualified tables");
    return pTableGroup;
  }
@@ -1970,7 +1970,7 @@ SArray* createTableGroup(SArray* pTableList, STSchema* pTagSchema, SColIndex* pC
    }
    taosArrayPush(pTableGroup, &sa);
-    uTrace("all %d tables belong to one group", size);
+    tsdbTrace("all %d tables belong to one group", size);
  } else {
    STableGroupSupporter *pSupp = (STableGroupSupporter *) calloc(1, sizeof(STableGroupSupporter));
    pSupp->tsdbMeta = tsdbGetMeta(tsdb);
@@ -2069,12 +2069,12 @@ int32_t tsdbQuerySTableByTagCond(TsdbRepoT* tsdb, uint64_t uid, const char* pTag
                                 SColIndex* pColIndex, int32_t numOfCols) {
  STable* pTable = tsdbGetTableByUid(tsdbGetMeta(tsdb), uid);
  if (pTable == NULL) {
-    uError("%p failed to get stable, uid:%" PRIu64, tsdb, uid);
+    tsdbError("%p failed to get stable, uid:%" PRIu64, tsdb, uid);
    return TSDB_CODE_INVALID_TABLE_ID;
  }
  if (pTable->type != TSDB_SUPER_TABLE) {
-    uError("%p query normal tag not allowed, uid:%" PRIu64 ", tid:%d, name:%s",
+    tsdbError("%p query normal tag not allowed, uid:%" PRIu64 ", tid:%d, name:%s",
           tsdb, uid, pTable->tableId.tid, pTable->name);
    return TSDB_CODE_OPS_NOT_SUPPORT; //basically, this error is caused by invalid sql issued by client
@@ -2090,7 +2090,7 @@ int32_t tsdbQuerySTableByTagCond(TsdbRepoT* tsdb, uint64_t uid, const char* pTag
      pGroupInfo->numOfTables = taosArrayGetSize(res);
      pGroupInfo->pGroupList  = createTableGroup(res, pTagSchema, pColIndex, numOfCols, tsdb);
-      uTrace("no tbname condition or tagcond, all tables belongs to one group, numOfTables:%d", pGroupInfo->numOfTables);
+      tsdbTrace("no tbname condition or tagcond, all tables belongs to one group, numOfTables:%d", pGroupInfo->numOfTables);
    } else {
      // todo add error
    }

--- a/src/util/inc/tcache.h
+++ b/src/util/inc/tcache.h
@@ -47,7 +47,7 @@ typedef struct SCacheDataNode {
 typedef struct STrashElem {
  struct STrashElem *prev;
  struct STrashElem *next;
-  SCacheDataNode *        pData;
+  SCacheDataNode    *pData;
 } STrashElem;
 typedef struct {

--- a/src/util/inc/tutil.h
+++ b/src/util/inc/tutil.h
@@ -118,7 +118,7 @@ extern "C" {
 int32_t strdequote(char *src);
-void strtrim(char *src);
+size_t strtrim(char *src);
 char *strnchr(char *haystack, char needle, int32_t len, bool skipquote);

--- a/src/util/src/hash.c
+++ b/src/util/src/hash.c
@@ -529,7 +529,7 @@ void taosHashTableResize(SHashObj *pHashObj) {
 }
 SHashNode *doCreateHashNode(const void *key, size_t keyLen, const void *pData, size_t dsize, uint32_t hashVal) {
-  size_t totalSize = dsize + sizeof(SHashNode) + keyLen + 1;  // one extra byte for null
+  size_t totalSize = dsize + sizeof(SHashNode) + keyLen;
  SHashNode *pNewNode = calloc(1, totalSize);
  if (pNewNode == NULL) {
@@ -544,7 +544,6 @@ SHashNode *doCreateHashNode(const void *key, size_t keyLen, const void *pData, s
  pNewNode->keyLen = keyLen;
  pNewNode->hashVal = hashVal;
  return pNewNode;
 }
@@ -559,7 +558,6 @@ SHashNode *doUpdateHashNode(SHashNode *pNode, const void *key, size_t keyLen, co
  memcpy(pNewNode->data, pData, dsize);
  pNewNode->key = pNewNode->data + dsize;
  assert(memcmp(pNewNode->key, key, keyLen) == 0 && keyLen == pNewNode->keyLen);
  memcpy(pNewNode->key, key, keyLen);

--- a/src/util/src/tcache.c
+++ b/src/util/src/tcache.c
@@ -77,7 +77,7 @@ static FORCE_INLINE void taosFreeNode(void *data) {
 * @param lifespan total survial expiredTime from now
 * @return         SCacheDataNode
 */
-static SCacheDataNode *taosCreateHashNode(const char *key, size_t keyLen, const char *pData, size_t size,
+static SCacheDataNode *taosCreateCacheNode(const char *key, size_t keyLen, const char *pData, size_t size,
                                          uint64_t duration) {
  size_t totalSize = size + sizeof(SCacheDataNode) + keyLen + 1;
@@ -242,13 +242,14 @@ static SCacheDataNode *taosUpdateCacheImpl(SCacheObj *pCacheObj, SCacheDataNode
  // only a node is not referenced by any other object, in-place update it
  if (T_REF_VAL_GET(pNode) == 0) {
-    size_t newSize = sizeof(SCacheDataNode) + dataSize + keyLen;
+    size_t newSize = sizeof(SCacheDataNode) + dataSize + keyLen + 1;
    pNewNode = (SCacheDataNode *)realloc(pNode, newSize);
    if (pNewNode == NULL) {
      return NULL;
    }
+    memset(pNewNode, 0, newSize);
    pNewNode->signature = (uint64_t)pNewNode;
    memcpy(pNewNode->data, pData, dataSize);
@@ -267,7 +268,7 @@ static SCacheDataNode *taosUpdateCacheImpl(SCacheObj *pCacheObj, SCacheDataNode
  } else {
    taosCacheMoveToTrash(pCacheObj, pNode);
-    pNewNode = taosCreateHashNode(key, keyLen, pData, dataSize, duration);
+    pNewNode = taosCreateCacheNode(key, keyLen, pData, dataSize, duration);
    if (pNewNode == NULL) {
      return NULL;
    }
@@ -293,7 +294,7 @@ static SCacheDataNode *taosUpdateCacheImpl(SCacheObj *pCacheObj, SCacheDataNode
 */
 static FORCE_INLINE SCacheDataNode *taosAddToCacheImpl(SCacheObj *pCacheObj, const char *key, size_t keyLen, const void *pData,
                                                       size_t dataSize, uint64_t duration) {
-  SCacheDataNode *pNode = taosCreateHashNode(key, keyLen, pData, dataSize, duration);
+  SCacheDataNode *pNode = taosCreateCacheNode(key, keyLen, pData, dataSize, duration);
  if (pNode == NULL) {
    return NULL;
  }

--- a/src/util/src/tutil.c
+++ b/src/util/src/tutil.c
@@ -60,7 +60,7 @@ int32_t strdequote(char *z) {
  return j + 1;  // only one quote, do nothing
 }
-void strtrim(char *z) {
+size_t strtrim(char *z) {
  int32_t i = 0;
  int32_t j = 0;
@@ -71,7 +71,7 @@ void strtrim(char *z) {
  if (z[j] == 0) {
    z[0] = 0;
-    return;
+    return 0;
  }
  delta = j;
@@ -89,9 +89,12 @@ void strtrim(char *z) {
  if (stop > 0) {
    z[stop - delta] = 0;
+    return (stop - delta);
  } else if (j != i) {
    z[i] = 0;
  }
+  return i;
 }
 char **strsplit(char *z, const char *delim, int32_t *num) {

--- a/src/util/tests/stringTest.cpp
+++ b/src/util/tests/stringTest.cpp
@@ -20,10 +20,10 @@ TEST(testCase, string_dequote_test) {
  EXPECT_STRCASEEQ(t1, "abc");
  char t21[] = " abc ";
-  strtrim(t21);
+  int32_t lx = strtrim(t21);
  EXPECT_STREQ("abc", t21);
-  EXPECT_EQ(3, strlen(t21));
+  EXPECT_EQ(3, lx);
 }
 TEST(testCase, string_replace_test) {

--- a/tests/examples/c/demo.c
+++ b/tests/examples/c/demo.c
@@ -26,13 +26,12 @@
 void taosMsleep(int mseconds);
 static int32_t doQuery(TAOS* taos, const char* sql) {
-  int32_t code = taos_query(taos, sql);
+  TAOS_RES* res = taos_query(taos, sql);
-  if (code != 0) {
+  if (taos_errno(res) != 0) {
    printf("failed to execute query, reason:%s\n", taos_errstr(taos));
    return -1;
  }
-  TAOS_RES* res = taos_use_result(taos);
  TAOS_ROW row = NULL;
  char buf[512] = {0};
@@ -46,7 +45,6 @@ static int32_t doQuery(TAOS* taos, const char* sql) {
  }
  taos_free_result(res);
  return 0;
 }
@@ -81,6 +79,7 @@ static __attribute__((unused)) void multiThreadTest(int32_t numOfThreads, void*
    pthread_join(threadId[i], NULL);
  }
+  free(threadId);
  pthread_attr_destroy(&thattr);
 }
@@ -114,19 +113,6 @@ int main(int argc, char *argv[]) {
 //    doQuery(taos, "insert into t1 values(now, 2)");
 //  }
 //  doQuery(taos, "create table t1(ts timestamp, k binary(12), f nchar(2))");
-//  doQuery(taos, "insert into tm0 values('2020-1-1 1:1:1', 'abc')");
-//  doQuery(taos, "create table if not exists tm0 (ts timestamp, k int);");
-//  doQuery(taos, "insert into tm0 values('2020-1-1 1:1:1', 1);");
-//  doQuery(taos, "insert into tm0 values('2020-1-1 1:1:2', 2);");
-//  doQuery(taos, "insert into tm0 values('2020-1-1 1:1:3', 3);");
-//  doQuery(taos, "insert into tm0 values('2020-1-1 1:1:4', 4);");
-//  doQuery(taos, "insert into tm0 values('2020-1-1 1:1:5', 5);");
-//  doQuery(taos, "insert into tm0 values('2020-1-1 1:1:6', 6);");
-//  doQuery(taos, "insert into tm0 values('2020-1-1 1:1:7', 7);");
-//  doQuery(taos, "insert into tm0 values('2020-1-1 1:1:8', 8);");
-//  doQuery(taos, "insert into tm0 values('2020-1-1 1:1:9', 9);");
-//  doQuery(taos, "select sum(k),count(*) from m1 group by a");
  taos_close(taos);
  return 0;
@@ -173,10 +159,6 @@ int main(int argc, char *argv[]) {
    exit(1);
  }
-  result = taos_use_result(taos);
  if (result == NULL) {
    printf("failed to get result, reason:%s\n", taos_errstr(taos));
    exit(1);

--- a/tests/pytest/crash_gen.py
+++ b/tests/pytest/crash_gen.py
@@ -609,7 +609,8 @@ class StateDbOnly(AnyState):
        ]
    def verifyTasksToState(self, tasks, newState):
-        self.assertAtMostOneSuccess(tasks, DropDbTask) # not true in massively parralel cases
+        if ( not self.hasTask(tasks, CreateDbTask) ):
+            self.assertAtMostOneSuccess(tasks, DropDbTask) # only if we don't create any more
        self.assertIfExistThenSuccess(tasks, DropDbTask)
        # self.assertAtMostOneSuccess(tasks, CreateFixedTableTask) # not true in massively parrallel cases
        # Nothing to be said about adding data task
@@ -619,7 +620,8 @@ class StateDbOnly(AnyState):
            # self._state = self.STATE_EMPTY
        elif ( self.hasSuccess(tasks, CreateFixedSuperTableTask) ): # did not drop db, create table success
            # self.assertHasTask(tasks, CreateFixedTableTask) # tried to create table
-            self.assertAtMostOneSuccess(tasks, CreateFixedSuperTableTask) # at most 1 attempt is successful
+            if ( not self.hasTask(tasks, DropFixedSuperTableTask) ): 
+                self.assertAtMostOneSuccess(tasks, CreateFixedSuperTableTask) # at most 1 attempt is successful, if we don't drop anything
            self.assertNoTask(tasks, DropDbTask) # should have have tried
            # if ( not self.hasSuccess(tasks, AddFixedDataTask) ): # just created table, no data yet
            #     # can't say there's add-data attempts, since they may all fail
@@ -674,7 +676,7 @@ class StateHasData(AnyState):
            if ( not self.hasTask(tasks, CreateDbTask)): # without a create_db task
                self.assertNoTask(tasks, DropDbTask) # we must have drop_db task
            self.hasSuccess(tasks, DropFixedSuperTableTask)
-            self.assertAtMostOneSuccess(tasks, DropFixedSuperTableTask) # TODO: dicy
+            # self.assertAtMostOneSuccess(tasks, DropFixedSuperTableTask) # TODO: dicy
        elif ( newState.equals(AnyState.STATE_TABLE_ONLY) ): # data deleted
            self.assertNoTask(tasks, DropDbTask)
            self.assertNoTask(tasks, DropFixedSuperTableTask)
@@ -689,9 +691,9 @@ class StateHasData(AnyState):
 # State of the database as we believe it to be
 class DbState():
-    def __init__(self):
+    def __init__(self, resetDb = True):
        self.tableNumQueue = LinearQueue()
-        self._lastTick = datetime.datetime(2019, 1, 1) # initial date time tick
+        self._lastTick = self.setupLastTick() # datetime.datetime(2019, 1, 1) # initial date time tick
        self._lastInt  = 0 # next one is initial integer 
        self._lock = threading.RLock()
@@ -712,12 +714,32 @@ class DbState():
        except:
            print("[=] Unexpected exception")
            raise        
-        self._dbConn.resetDb() # drop and recreate DB
-        self._state = StateEmpty() # initial state, the result of above
+        if resetDb :
+            self._dbConn.resetDb() # drop and recreate DB            
+        self._state = self._findCurrentState()
    def getDbConn(self):
        return self._dbConn
+    def getState(self):
+        return self._state
+    # We aim to create a starting time tick, such that, whenever we run our test here once
+    # We should be able to safely create 100,000 records, which will not have any repeated time stamp
+    # when we re-run the test in 3 minutes (180 seconds), basically we should expand time duration
+    # by a factor of 500.
+    # TODO: what if it goes beyond 10 years into the future
+    def setupLastTick(self):
+        t1 = datetime.datetime(2020, 5, 30)
+        t2 = datetime.datetime.now()
+        elSec = t2.timestamp() - t1.timestamp()
+        # print("elSec = {}".format(elSec))
+        t3 = datetime.datetime(2012, 1, 1) # default "keep" is 10 years
+        t4 = datetime.datetime.fromtimestamp( t3.timestamp() + elSec * 500) # see explanation above
+        logger.info("Setting up TICKS to start from: {}".format(t4))
+        return t4
    def pickAndAllocateTable(self): # pick any table, and "use" it
        return self.tableNumQueue.pickAndAllocate()
@@ -743,7 +765,7 @@ class DbState():
            return self._lastInt
    def getNextBinary(self):
-        return "Los_Angeles_{}".format(self.getNextInt())
+        return "Beijing_Shanghai_Los_Angeles_New_York_San_Francisco_Chicago_Beijing_Shanghai_Los_Angeles_New_York_San_Francisco_Chicago_{}".format(self.getNextInt())
    def getNextFloat(self):
        return 0.9 + self.getNextInt()
@@ -1089,7 +1111,7 @@ class CreateFixedSuperTableTask(StateTransitionTask):
    def _executeInternal(self, te: TaskExecutor, wt: WorkerThread):
        tblName = self._dbState.getFixedSuperTableName()        
-        wt.execSql("create table db.{} (ts timestamp, speed int) tags (b binary(20), f float) ".format(tblName))
+        wt.execSql("create table db.{} (ts timestamp, speed int) tags (b binary(200), f float) ".format(tblName))
        # No need to create the regular tables, INSERT will do that automatically
@@ -1148,12 +1170,13 @@ class AddFixedDataTask(StateTransitionTask):
        ds = self._dbState
        wt.execSql("use db") # TODO: seems to be an INSERT bug to require this
        for i in range(10): # 0 to 9
-            sql = "insert into db.reg_table_{} using {} tags ('{}', {}) values ('{}', {});".format(
+            for j in range(10) :
-                i, 
+                sql = "insert into db.reg_table_{} using {} tags ('{}', {}) values ('{}', {});".format(
-                ds.getFixedSuperTableName(), 
+                    i, 
-                ds.getNextBinary(), ds.getNextFloat(),
+                    ds.getFixedSuperTableName(), 
-                ds.getNextTick(), ds.getNextInt())
+                    ds.getNextBinary(), ds.getNextFloat(),
-            wt.execSql(sql) 
+                    ds.getNextTick(), ds.getNextInt())
+                wt.execSql(sql) 
 #---------- Non State-Transition Related Tasks ----------#
@@ -1301,7 +1324,9 @@ def main():
    ch = logging.StreamHandler()
    logger.addHandler(ch)
-    dbState = DbState()
+    # resetDb = False # DEBUG only
+    # dbState = DbState(resetDb)  # DBEUG only!
+    dbState = DbState() # Regular function
    Dice.seed(0) # initial seeding of dice
    tc = ThreadCoordinator(
        ThreadPool(dbState, gConfig.num_threads, gConfig.max_steps, 0), 
@@ -1309,6 +1334,43 @@ def main():
        dbState
        )
+    # # Hack to exercise reading from disk, imcreasing coverage. TODO: fix
+    # dbc = dbState.getDbConn()
+    # sTbName = dbState.getFixedSuperTableName()   
+    # dbc.execute("create database if not exists db")
+    # if not dbState.getState().equals(StateEmpty()):
+    #     dbc.execute("use db")     
+    # rTables = None
+    # try: # the super table may not exist
+    #     sql = "select TBNAME from db.{}".format(sTbName)
+    #     logger.info("Finding out tables in super table: {}".format(sql))
+    #     dbc.query(sql) # TODO: analyze result set later
+    #     logger.info("Fetching result")
+    #     rTables = dbc.getQueryResult()
+    #     logger.info("Result: {}".format(rTables))
+    # except taos.error.ProgrammingError as err:
+    #     logger.info("Initial Super table OPS error: {}".format(err))
+    # # sys.exit()
+    # if ( not rTables == None):
+    #     # print("rTables[0] = {}, type = {}".format(rTables[0], type(rTables[0])))
+    #     try:
+    #         for rTbName in rTables : # regular tables
+    #             ds = dbState
+    #             logger.info("Inserting into table: {}".format(rTbName[0]))
+    #             sql = "insert into db.{} values ('{}', {});".format(
+    #                 rTbName[0],                    
+    #                 ds.getNextTick(), ds.getNextInt())
+    #             dbc.execute(sql)
+    #         for rTbName in rTables : # regular tables        
+    #             dbc.query("select * from db.{}".format(rTbName[0])) # TODO: check success failure
+    #         logger.info("Initial READING operation is successful")       
+    #     except taos.error.ProgrammingError as err:
+    #         logger.info("Initial WRITE/READ error: {}".format(err))   
    # Sandbox testing code
    # dbc = dbState.getDbConn()
    # while True:

--- a/tests/pytest/crash_gen_0519.py
+++ b/tests/pytest/crash_gen_0519.py
--- a/tests/pytest/crash_gen_0519.sh
+++ b/tests/pytest/crash_gen_0519.sh
-#!/bin/bash
-# This is the script for us to try to cause the TDengine server or client to crash
-#    
-# PREPARATION
-#
-# 1. Build an compile the TDengine source code that comes with this script, in the same directory tree
-# 2. Please follow the direction in our README.md, and build TDengine in the build/ directory
-# 3. Adjust the configuration file if needed under build/test/cfg/taos.cfg
-# 4. Run the TDengine server instance: cd build; ./build/bin/taosd -c test/cfg
-# 5. Make sure you have a working Python3 environment: run /usr/bin/python3 --version, and you should get 3.6 or above
-# 6. Make sure you have the proper Python packages: # sudo apt install python3-setuptools python3-pip python3-distutils
-#
-# RUNNING THIS SCRIPT
-# 
-# This script assumes the source code directory is intact, and that the binaries has been built in the
-# build/ directory, as such, will will load the Python libraries in the directory tree, and also load
-# the TDengine client shared library (so) file, in the build/directory, as evidenced in the env
-# variables below.
-#
-# Running the script is simple, no parameter is needed (for now, but will change in the future).
-#
-# Happy Crashing...
-# Due to the heavy path name assumptions/usage, let us require that the user be in the current directory
-EXEC_DIR=`dirname "$0"`
-if [[ $EXEC_DIR != "." ]]
-then
-    echo "ERROR: Please execute `basename "$0"` in its own directory (for now anyway, pardon the dust)"
-    exit -1
-fi
-# First we need to set up a path for Python to find our own TAOS modules, so that "import" can work.
-export PYTHONPATH=$(pwd)/../../src/connector/python/linux/python3
-# Then let us set up the library path so that our compiled SO file can be loaded by Python
-export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$(pwd)/../../build/build/lib
-# Now we are all let, and let's see if we can find a crash. Note we pass all params
-./crash_gen_0519.py $@
--- a/tests/pytest/fulltest.sh
+++ b/tests/pytest/fulltest.sh
@@ -131,6 +131,6 @@ python3 ./test.py -f user/pass_len.py
 #query
 python3 ./test.py -f query/filter.py
-python3 ./test.py $1 -f query/filterCombo.py
+python3 ./test.py -f query/filterCombo.py
-python3 ./test.py $1 -f query/queryNormal.py
+python3 ./test.py -f query/queryNormal.py
-python3 ./test.py $1 -f query/queryError.py
+python3 ./test.py -f query/queryError.py
--- a/tests/script/general/field/binary.sim
+++ b/tests/script/general/field/binary.sim
--- a/tests/script/general/parser/limit2_query.sim
+++ b/tests/script/general/parser/limit2_query.sim
--- a/tests/script/general/parser/testSuite.sim
+++ b/tests/script/general/parser/testSuite.sim
--- a/tests/script/unique/http/opentsdb.sim
+++ b/tests/script/unique/http/opentsdb.sim
--- a/tests/test-all.sh
+++ b/tests/test-all.sh
--- a/tests/test/c/importOneRow.c
+++ b/tests/test/c/importOneRow.c
--- a/tests/tsim/src/simExe.c
+++ b/tests/tsim/src/simExe.c