Merge branch 'feature/query' of https://github.com/taosdata/TDengine into feature/query

src/client/src/tscSql.c

@@ -724,6 +724,13 @@ int taos_print_row(char *str, TAOS_ROW row, TAOS_FIELD *fields, int num_fields)
   return len;
 }
 
+static void asyncCallback(void *param, TAOS_RES *tres, int code) {
+  assert(param != NULL);
+  SSqlObj *pSql = ((SSqlObj *)param);
+  pSql->res.code = code;
+  sem_post(&pSql->rspSem);
+}
+
 int taos_validate_sql(TAOS *taos, const char *sql) {
   STscObj *pObj = (STscObj *)taos;
   if (pObj == NULL || pObj->signature != pObj) {
@@ -732,7 +739,8 @@ int taos_validate_sql(TAOS *taos, const char *sql) {
   }
 
   SSqlObj* pSql = calloc(1, sizeof(SSqlObj));
-  
+  pSql->pTscObj = taos;
+  pSql->signature = pSql;
   SSqlRes *pRes = &pSql->res;
   SSqlCmd *pCmd = &pSql->cmd;
   
@@ -766,10 +774,17 @@ int taos_validate_sql(TAOS *taos, const char *sql) {
     pCmd->pTableList = NULL;
   }
 
-  pRes->code = (uint8_t)tsParseSql(pSql, false);
-  int code = pRes->code;
-
-  tscDebug("%p Valid SQL result:%d, %s pObj:%p", pSql, pRes->code, taos_errstr(taos), pObj);
+  pSql->fp = asyncCallback;
+  pSql->fetchFp = asyncCallback;
+  pSql->param = pSql;
+  int code = tsParseSql(pSql, true);
+  if (code == TSDB_CODE_TSC_ACTION_IN_PROGRESS) {
+    sem_wait(&pSql->rspSem);
+    code = pSql->res.code;
+  }
+  if (code != TSDB_CODE_SUCCESS) {
+    tscDebug("%p Valid SQL result:%d, %s pObj:%p", pSql, code, taos_errstr(taos), pObj);
+  }
   taos_free_result(pSql);
 
   return code;
@@ -865,6 +880,8 @@ int taos_load_table_info(TAOS *taos, const char *tableNameList) {
   }
 
   SSqlObj* pSql = calloc(1, sizeof(SSqlObj));
+  pSql->pTscObj = taos;
+  pSql->signature = pSql;
   SSqlRes *pRes = &pSql->res;
 
   pRes->numOfTotal = 0;  // the number of getting table meta from server

src/client/src/tscStream.c

@@ -122,7 +122,7 @@ static void tscProcessStreamTimer(void *handle, void *tmrId) {
       pQueryInfo->window.ekey = pStream->etime;
     }
   } else {
-    pQueryInfo->window.skey = pStream->stime - pStream->interval;
+    pQueryInfo->window.skey = pStream->stime;
     int64_t etime = taosGetTimestamp(pStream->precision);
     // delay to wait all data in last time window
     if (pStream->precision == TSDB_TIME_PRECISION_MICRO) {
@@ -232,6 +232,9 @@ static void tscProcessStreamRetrieveResult(void *param, TAOS_RES *res, int numOf
       (*pStream->fp)(pStream->param, res, row);
     }
 
+    if (!pStream->isProject) {
+      pStream->stime += pStream->slidingTime;
+    }
     // actually only one row is returned. this following is not necessary
     taos_fetch_rows_a(res, tscProcessStreamRetrieveResult, pStream);
   } else {  // numOfRows == 0, all data has been retrieved
@@ -432,6 +435,7 @@ static int64_t tscGetStreamStartTimestamp(SSqlObj *pSql, SSqlStream *pStream, in
   } else {             // timewindow based aggregation stream
     if (stime == 0) {  // no data in meter till now
       stime = ((int64_t)taosGetTimestamp(pStream->precision) / pStream->interval) * pStream->interval;
+      stime -= pStream->interval;
       tscWarn("%p stream:%p, last timestamp:0, reset to:%" PRId64, pSql, pStream, stime);
     } else {
       int64_t newStime = (stime / pStream->interval) * pStream->interval;

src/client/src/tscSub.c

@@ -34,6 +34,7 @@ typedef struct SSubscriptionProgress {
 typedef struct SSub {
   void *                  signature;
   char                    topic[32];
+  sem_t                   sem;
   int64_t                 lastSyncTime;
   int64_t                 lastConsumeTime;
   TAOS *                  taos;
@@ -83,84 +84,108 @@ void tscUpdateSubscriptionProgress(void* sub, int64_t uid, TSKEY ts) {
 
 static void asyncCallback(void *param, TAOS_RES *tres, int code) {
   assert(param != NULL);
-  SSqlObj *pSql = ((SSqlObj *)param);
-  
-  pSql->res.code = code;
-  sem_post(&pSql->rspSem);
+  SSub *pSub = ((SSub *)param);
+  pSub->pSql->res.code = code;
+  sem_post(&pSub->sem);
 }
 
 
 static SSub* tscCreateSubscription(STscObj* pObj, const char* topic, const char* sql) {
-  SSub* pSub = NULL;
-
-  TRY( 8 ) {
-    SSqlObj* pSql = calloc_throw(1, sizeof(SSqlObj));
-    CLEANUP_PUSH_FREE(true, pSql);
-    SSqlCmd *pCmd = &pSql->cmd;
-    SSqlRes *pRes = &pSql->res;
-
-    if (tsem_init(&pSql->rspSem, 0, 0) == -1) {
-      THROW(TAOS_SYSTEM_ERROR(errno));
-    }
-    CLEANUP_PUSH_INT_PTR(true, tsem_destroy, &pSql->rspSem);
+  int code = TSDB_CODE_SUCCESS, line = __LINE__;
+  SSqlObj* pSql = NULL;
 
-    pSql->signature = pSql;
-    pSql->param = pSql;
-    pSql->pTscObj = pObj;
-    pSql->maxRetry = TSDB_MAX_REPLICA;
-    pSql->fp = asyncCallback;
-
-    int code = tscAllocPayload(pCmd, TSDB_DEFAULT_PAYLOAD_SIZE);
-    if (code != TSDB_CODE_SUCCESS) {
-      THROW(code);
-    }
-    CLEANUP_PUSH_FREE(true, pCmd->payload);
+  SSub* pSub = calloc(1, sizeof(SSub));
+  if (pSub == NULL) {
+    line = __LINE__;
+    code = TSDB_CODE_TSC_OUT_OF_MEMORY;
+    goto fail;
+  }
+  pSub->signature = pSub;
+  if (tsem_init(&pSub->sem, 0, 0) == -1) {
+    line = __LINE__;
+    code = TAOS_SYSTEM_ERROR(errno);
+    goto fail;
+  }
+  tstrncpy(pSub->topic, topic, sizeof(pSub->topic));
+  pSub->progress = taosArrayInit(32, sizeof(SSubscriptionProgress));
+  if (pSub->progress == NULL) {
+    line = __LINE__;
+    code = TSDB_CODE_TSC_OUT_OF_MEMORY;
+    goto fail;
+  }
 
-    pRes->qhandle = 0;
-    pRes->numOfRows = 1;
+  pSql = calloc(1, sizeof(SSqlObj));
+  if (pSql == NULL) {
+    line = __LINE__;
+    code = TSDB_CODE_TSC_OUT_OF_MEMORY;
+    goto fail;
+  }
+  pSql->signature = pSql;
+  pSql->pTscObj = pObj;
+  pSql->pSubscription = pSub;
+  pSub->pSql = pSql;
 
-    pSql->sqlstr = strdup_throw(sql);
-    CLEANUP_PUSH_FREE(true, pSql->sqlstr);
-    strtolower(pSql->sqlstr, pSql->sqlstr);
+  SSqlCmd* pCmd = &pSql->cmd;
+  SSqlRes* pRes = &pSql->res;
+  if (tsem_init(&pSql->rspSem, 0, 0) == -1) {
+    line = __LINE__;
+    code = TAOS_SYSTEM_ERROR(errno);
+    goto fail;
+  }
 
-    code = tsParseSql(pSql, false);
-    if (code == TSDB_CODE_TSC_ACTION_IN_PROGRESS) {
-      // wait for the callback function to post the semaphore
-      sem_wait(&pSql->rspSem);
-      code = pSql->res.code;
-    }
-    if (code != TSDB_CODE_SUCCESS) {
-      tscError("failed to parse sql statement: %s, error: %s", pSub->topic, tstrerror(code));
-      THROW( code );
-    }
+  pSql->param = pSub;
+  pSql->maxRetry = TSDB_MAX_REPLICA;
+  pSql->fp = asyncCallback;
+  pSql->fetchFp = asyncCallback;
+  pSql->sqlstr = strdup(sql);
+  if (pSql->sqlstr == NULL) {
+    line = __LINE__;
+    code = TSDB_CODE_TSC_OUT_OF_MEMORY;
+    goto fail;
+  }
+  strtolower(pSql->sqlstr, pSql->sqlstr);
+  pRes->qhandle = 0;
+  pRes->numOfRows = 1;
+
+  code = tscAllocPayload(pCmd, TSDB_DEFAULT_PAYLOAD_SIZE);
+  if (code != TSDB_CODE_SUCCESS) {
+    line = __LINE__;
+    goto fail;
+  }
 
-    if (pSql->cmd.command != TSDB_SQL_SELECT) {
-      tscError("only 'select' statement is allowed in subscription: %s", pSub->topic);
-      THROW( -1 );  // TODO
-    }
+  code = tsParseSql(pSql, false);
+  if (code == TSDB_CODE_TSC_ACTION_IN_PROGRESS) {
+    sem_wait(&pSub->sem);
+    code = pSql->res.code;
+  }
+  if (code != TSDB_CODE_SUCCESS) {
+    line = __LINE__;
+    goto fail;
+  }
 
-    pSub = calloc_throw(1, sizeof(SSub));
-    CLEANUP_PUSH_FREE(true, pSub);
-    pSql->pSubscription = pSub;
-    pSub->pSql = pSql;
-    pSub->signature = pSub;
-    strncpy(pSub->topic, topic, sizeof(pSub->topic));
-    pSub->topic[sizeof(pSub->topic) - 1] = 0;
-    pSub->progress = taosArrayInit(32, sizeof(SSubscriptionProgress));
-    if (pSub->progress == NULL) {
-      THROW(TSDB_CODE_TSC_OUT_OF_MEMORY);
-    }
+  if (pSql->cmd.command != TSDB_SQL_SELECT) {
+    line = __LINE__;
+    code = TSDB_CODE_TSC_INVALID_SQL;
+    goto fail;
+  }
 
-    CLEANUP_EXECUTE();
+  return pSub;
 
-  } CATCH( code ) {
-    tscError("failed to create subscription object: %s", tstrerror(code));
-    CLEANUP_EXECUTE();
+fail:
+  tscError("tscCreateSubscription failed at line %d, reason: %s", line, tstrerror(code));
+  if (pSql != NULL) {
+    tscFreeSqlObj(pSql);
+    pSql = NULL;
+  }
+  if (pSub != NULL) {
+    taosArrayDestroy(pSub->progress);
+    tsem_destroy(&pSub->sem);
+    free(pSub);
     pSub = NULL;
+  }
 
-  } END_TRY
-
-  return pSub;
+  terrno = code;
+  return NULL;
 }
 
 
@@ -405,9 +430,10 @@ TAOS_RES *taos_consume(TAOS_SUB *tsub) {
     tscGetTableMetaInfoFromCmd(&pSql->cmd, 0, 0)->vgroupIndex = 0;
 
     pSql->fp = asyncCallback;
-    pSql->param = pSql;
+    pSql->fetchFp = asyncCallback;
+    pSql->param = pSub;
     tscDoQuery(pSql);
-    sem_wait(&pSql->rspSem);
+    sem_wait(&pSub->sem);
 
     if (pRes->code != TSDB_CODE_SUCCESS) {
       continue;
@@ -437,7 +463,9 @@ void taos_unsubscribe(TAOS_SUB *tsub, int keepProgress) {
   }
 
   if (keepProgress) {
-    tscSaveSubscriptionProgress(pSub);
+    if (pSub->progress != NULL) {
+      tscSaveSubscriptionProgress(pSub);
+    }
   } else {
     char path[256];
     sprintf(path, "%s/subscribe/%s", tsDataDir, pSub->topic);
@@ -448,6 +476,7 @@ void taos_unsubscribe(TAOS_SUB *tsub, int keepProgress) {
 
   tscFreeSqlObj(pSub->pSql);
   taosArrayDestroy(pSub->progress);
+  tsem_destroy(&pSub->sem);
   memset(pSub, 0, sizeof(*pSub));
   free(pSub);
 }

src/inc/taos.h

@@ -67,8 +67,6 @@ DLL_EXPORT void  taos_init();
 DLL_EXPORT void  taos_cleanup();
 DLL_EXPORT int   taos_options(TSDB_OPTION option, const void *arg, ...);
 DLL_EXPORT TAOS *taos_connect(const char *ip, const char *user, const char *pass, const char *db, uint16_t port);
-DLL_EXPORT TAOS *taos_connect_c(const char *ip, uint8_t ipLen, const char *user, uint8_t userLen,
-                 const char *pass, uint8_t passLen, const char *db, uint8_t dbLen, uint16_t port);
 DLL_EXPORT void  taos_close(TAOS *taos);
 
 typedef struct TAOS_BIND {
@@ -90,7 +88,6 @@ TAOS_RES * taos_stmt_use_result(TAOS_STMT *stmt);
 int        taos_stmt_close(TAOS_STMT *stmt);
 
 DLL_EXPORT TAOS_RES *taos_query(TAOS *taos, const char *sql);
-DLL_EXPORT TAOS_RES *taos_query_c(TAOS *taos, const char *sql, uint32_t sqlLen);
 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);

src/query/src/qExecutor.c

@@ -4964,7 +4964,7 @@ static void tableMultiOutputProcess(SQInfo *pQInfo, STableQueryInfo* pTableInfo)
         pQuery->current->lastKey, pQuery->window.ekey);
   } else if (Q_STATUS_EQUAL(pQuery->status, QUERY_COMPLETED)) {
     STableIdInfo tidInfo;
-    STableId* id = TSDB_TABLEID(pQuery->current);
+    STableId* id = TSDB_TABLEID(pQuery->current->pTable);
 
     tidInfo.uid = id->uid;
     tidInfo.tid = id->tid;

tests/examples/c/apitest.c

+// sample code to verify all TDengine API
+// to compile: gcc -o apitest apitest.c -ltaos
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <taos.h>
+#include <unistd.h>
+
+
+static void prepare_data(TAOS* taos) {
+  taos_query(taos, "drop database if exists test;");
+  usleep(100000);
+  taos_query(taos, "create database test;");
+  usleep(100000);
+  taos_select_db(taos, "test");
+
+  taos_query(taos, "create table meters(ts timestamp, a int) tags(area int);");
+
+  taos_query(taos, "create table t0 using meters tags(0);");
+  taos_query(taos, "create table t1 using meters tags(1);");
+  taos_query(taos, "create table t2 using meters tags(2);");
+  taos_query(taos, "create table t3 using meters tags(3);");
+  taos_query(taos, "create table t4 using meters tags(4);");
+  taos_query(taos, "create table t5 using meters tags(5);");
+  taos_query(taos, "create table t6 using meters tags(6);");
+  taos_query(taos, "create table t7 using meters tags(7);");
+  taos_query(taos, "create table t8 using meters tags(8);");
+  taos_query(taos, "create table t9 using meters tags(9);");
+
+  TAOS_RES* res = taos_query(taos, "insert into t0 values('2020-01-01 00:00:00.000', 0)"
+    " ('2020-01-01 00:01:00.000', 0)"
+    " ('2020-01-01 00:02:00.000', 0)"
+    " t1 values('2020-01-01 00:00:00.000', 0)"
+    " ('2020-01-01 00:01:00.000', 0)"
+    " ('2020-01-01 00:02:00.000', 0)"
+    " ('2020-01-01 00:03:00.000', 0)"
+    " t2 values('2020-01-01 00:00:00.000', 0)"
+    " ('2020-01-01 00:01:00.000', 0)"
+    " ('2020-01-01 00:01:01.000', 0)"
+    " ('2020-01-01 00:01:02.000', 0)"
+    " t3 values('2020-01-01 00:01:02.000', 0)"
+    " t4 values('2020-01-01 00:01:02.000', 0)"
+    " t5 values('2020-01-01 00:01:02.000', 0)"
+    " t6 values('2020-01-01 00:01:02.000', 0)"
+    " t7 values('2020-01-01 00:01:02.000', 0)"
+    " t8 values('2020-01-01 00:01:02.000', 0)"
+    " t9 values('2020-01-01 00:01:02.000', 0)");
+  int affected = taos_affected_rows(res);
+  if (affected != 18) {
+    printf("\033[31m%d rows affected by last insert statement, but it should be 18\033[0m\n", affected);
+  }
+  // super tables subscription
+  usleep(1000000);
+}
+
+
+static int print_result(TAOS_RES* res, int blockFetch) {
+  TAOS_ROW    row = NULL;
+  int         num_fields = taos_num_fields(res);
+  TAOS_FIELD* fields = taos_fetch_fields(res);
+  int         nRows = 0;
+
+  if (blockFetch) {
+    int rows = 0;
+    while ((rows = taos_fetch_block(res, &row))) {
+      for (int i = 0; i < rows; i++) {
+        char temp[256];
+        taos_print_row(temp, row + i, fields, num_fields);
+        puts(temp);
+      }
+      nRows += rows;
+    }
+  } else {
+    while ((row = taos_fetch_row(res))) {
+      char temp[256];
+      taos_print_row(temp, row, fields, num_fields);
+      puts(temp);
+      nRows++;
+    }
+  }
+
+  printf("%d rows consumed.\n", nRows);
+  return nRows;
+}
+
+
+static void check_row_count(int line, TAOS_RES* res, int expected) {
+  int actual = print_result(res, expected % 2);
+  if (actual != expected) {
+    printf("\033[31mline %d: row count mismatch, expected: %d, actual: %d\033[0m\n", line, expected, actual);
+  } else {
+    printf("line %d: %d rows consumed as expected\n", line, actual);
+  }
+}
+
+
+static void verify_query(TAOS* taos) {
+  prepare_data(taos);
+
+  int code = taos_load_table_info(taos, "t0,t1,t2,t3,t4,t5,t6,t7,t8,t9");
+  if (code != 0) {
+    printf("\033[31mfailed to load table info: 0x%08x\033[0m\n", code);
+  }
+
+  code = taos_validate_sql(taos, "select * from nonexisttable");
+  if (code == 0) {
+    printf("\033[31mimpossible, the table does not exists\033[0m\n");
+  }
+
+  code = taos_validate_sql(taos, "select * from meters");
+  if (code != 0) {
+    printf("\033[31mimpossible, the table does exists: 0x%08x\033[0m\n", code);
+  }
+
+  TAOS_RES* res = taos_query(taos, "select * from meters");
+  check_row_count(__LINE__, res, 18);
+  printf("result precision is: %d\n",  taos_result_precision(res));
+  int c = taos_field_count(res);
+  printf("field count is: %d\n",  c);
+  int* lengths = taos_fetch_lengths(res);
+  for (int i = 0; i < c; i++) {
+    printf("length of column %d is %d\n", i, lengths[i]);
+  }
+  taos_free_result(res);
+
+  res = taos_query(taos, "select * from t0");
+  check_row_count(__LINE__, res, 3);
+  taos_free_result(res);
+
+  res = taos_query(taos, "select * from nonexisttable");
+  code = taos_errno(res);
+  printf("code=%d, error msg=%s\n", code, taos_errstr(res));
+  taos_free_result(res);
+
+  res = taos_query(taos, "select * from meters");
+  taos_stop_query(res);
+}
+
+
+void subscribe_callback(TAOS_SUB* tsub, TAOS_RES *res, void* param, int code) {
+  int rows = print_result(res, *(int*)param);
+  printf("%d rows consumed in subscribe_callback\n", rows);
+}
+
+static void verify_subscribe(TAOS* taos) {
+  prepare_data(taos);
+
+  TAOS_SUB* tsub = taos_subscribe(taos, 0, "test", "select * from meters;", NULL, NULL, 0);
+  TAOS_RES* res = taos_consume(tsub);
+  check_row_count(__LINE__, res, 18);
+
+  res = taos_consume(tsub);
+  check_row_count(__LINE__, res, 0);
+
+  taos_query(taos, "insert into t0 values('2020-01-01 00:02:00.001', 0);");
+  taos_query(taos, "insert into t8 values('2020-01-01 00:01:03.000', 0);");
+  res = taos_consume(tsub);
+  check_row_count(__LINE__, res, 2);
+
+  taos_query(taos, "insert into t2 values('2020-01-01 00:01:02.001', 0);");
+  taos_query(taos, "insert into t1 values('2020-01-01 00:03:00.001', 0);");
+  res = taos_consume(tsub);
+  check_row_count(__LINE__, res, 2);
+
+  taos_query(taos, "insert into t1 values('2020-01-01 00:03:00.002', 0);");
+  res = taos_consume(tsub);
+  check_row_count(__LINE__, res, 1);
+
+  // keep progress information and restart subscription
+  taos_unsubscribe(tsub, 1);
+  taos_query(taos, "insert into t0 values('2020-01-01 00:04:00.000', 0);");
+  tsub = taos_subscribe(taos, 1, "test", "select * from meters;", NULL, NULL, 0);
+  res = taos_consume(tsub);
+  check_row_count(__LINE__, res, 24);
+
+  // keep progress information and continue previous subscription
+  taos_unsubscribe(tsub, 1);
+  tsub = taos_subscribe(taos, 0, "test", "select * from meters;", NULL, NULL, 0);
+  res = taos_consume(tsub);
+  check_row_count(__LINE__, res, 0);
+
+  // don't keep progress information and continue previous subscription
+  taos_unsubscribe(tsub, 0);
+  tsub = taos_subscribe(taos, 0, "test", "select * from meters;", NULL, NULL, 0);
+  res = taos_consume(tsub);
+  check_row_count(__LINE__, res, 24);
+
+  // single meter subscription
+
+  taos_unsubscribe(tsub, 0);
+  tsub = taos_subscribe(taos, 0, "test", "select * from t0;", NULL, NULL, 0);
+  res = taos_consume(tsub);
+  check_row_count(__LINE__, res, 5);
+
+  res = taos_consume(tsub);
+  check_row_count(__LINE__, res, 0);
+
+  taos_query(taos, "insert into t0 values('2020-01-01 00:04:00.001', 0);");
+  res = taos_consume(tsub);
+  check_row_count(__LINE__, res, 1);
+
+  taos_unsubscribe(tsub, 0);
+
+  int blockFetch = 0;
+  tsub = taos_subscribe(taos, 1, "test", "select * from meters;", subscribe_callback, &blockFetch, 1000);
+  usleep(2000000);
+  taos_query(taos, "insert into t0 values('2020-01-01 00:05:00.001', 0);");
+  usleep(2000000);
+  taos_unsubscribe(tsub, 0);
+}
+
+
+void verify_prepare(TAOS* taos) {
+  TAOS_RES* result = taos_query(taos, "drop database if exists test;");
+  usleep(100000);
+  taos_query(taos, "create database test;");
+
+  int code = taos_errno(result);
+  if (code != 0) {
+    printf("\033[31mfailed to create database, reason:%s\033[0m\n", taos_errstr(result));
+    taos_free_result(result);
+    return;
+  }
+  taos_free_result(result);
+
+  usleep(100000);
+  taos_select_db(taos, "test");
+
+  // create table
+  const char* sql = "create table m1 (ts timestamp, b bool, v1 tinyint, v2 smallint, v4 int, v8 bigint, f4 float, f8 double, bin binary(40), blob nchar(10))";
+  result = taos_query(taos, sql);
+  code = taos_errno(result);
+  if (code != 0) {
+    printf("\033[31mfailed to create table, reason:%s\033[0m\n", taos_errstr(result));
+    taos_free_result(result);
+    return;
+  }
+  taos_free_result(result);
+
+  // insert 10 records
+  struct {
+      int64_t ts;
+      int8_t b;
+      int8_t v1;
+      int16_t v2;
+      int32_t v4;
+      int64_t v8;
+      float f4;
+      double f8;
+      char bin[40];
+      char blob[80];
+  } v = {0};
+
+  TAOS_STMT* stmt = taos_stmt_init(taos);
+  TAOS_BIND params[10];
+  params[0].buffer_type = TSDB_DATA_TYPE_TIMESTAMP;
+  params[0].buffer_length = sizeof(v.ts);
+  params[0].buffer = &v.ts;
+  params[0].length = &params[0].buffer_length;
+  params[0].is_null = NULL;
+
+  params[1].buffer_type = TSDB_DATA_TYPE_BOOL;
+  params[1].buffer_length = sizeof(v.b);
+  params[1].buffer = &v.b;
+  params[1].length = &params[1].buffer_length;
+  params[1].is_null = NULL;
+
+  params[2].buffer_type = TSDB_DATA_TYPE_TINYINT;
+  params[2].buffer_length = sizeof(v.v1);
+  params[2].buffer = &v.v1;
+  params[2].length = &params[2].buffer_length;
+  params[2].is_null = NULL;
+
+  params[3].buffer_type = TSDB_DATA_TYPE_SMALLINT;
+  params[3].buffer_length = sizeof(v.v2);
+  params[3].buffer = &v.v2;
+  params[3].length = &params[3].buffer_length;
+  params[3].is_null = NULL;
+
+  params[4].buffer_type = TSDB_DATA_TYPE_INT;
+  params[4].buffer_length = sizeof(v.v4);
+  params[4].buffer = &v.v4;
+  params[4].length = &params[4].buffer_length;
+  params[4].is_null = NULL;
+
+  params[5].buffer_type = TSDB_DATA_TYPE_BIGINT;
+  params[5].buffer_length = sizeof(v.v8);
+  params[5].buffer = &v.v8;
+  params[5].length = &params[5].buffer_length;
+  params[5].is_null = NULL;
+
+  params[6].buffer_type = TSDB_DATA_TYPE_FLOAT;
+  params[6].buffer_length = sizeof(v.f4);
+  params[6].buffer = &v.f4;
+  params[6].length = &params[6].buffer_length;
+  params[6].is_null = NULL;
+
+  params[7].buffer_type = TSDB_DATA_TYPE_DOUBLE;
+  params[7].buffer_length = sizeof(v.f8);
+  params[7].buffer = &v.f8;
+  params[7].length = &params[7].buffer_length;
+  params[7].is_null = NULL;
+
+  params[8].buffer_type = TSDB_DATA_TYPE_BINARY;
+  params[8].buffer_length = sizeof(v.bin);
+  params[8].buffer = v.bin;
+  params[8].length = &params[8].buffer_length;
+  params[8].is_null = NULL;
+
+  strcpy(v.blob, "一二三四五六七八九十");
+  params[9].buffer_type = TSDB_DATA_TYPE_NCHAR;
+  params[9].buffer_length = strlen(v.blob);
+  params[9].buffer = v.blob;
+  params[9].length = &params[9].buffer_length;
+  params[9].is_null = NULL;
+
+  int is_null = 1;
+
+  sql = "insert into m1 values(?,?,?,?,?,?,?,?,?,?)";
+  code = taos_stmt_prepare(stmt, sql, 0);
+  if (code != 0){
+    printf("\033[31mfailed to execute taos_stmt_prepare. code:0x%x\033[0m\n", code);
+  }
+  v.ts = 1591060628000;
+  for (int i = 0; i < 10; ++i) {
+    v.ts += 1;
+    for (int j = 1; j < 10; ++j) {
+      params[j].is_null = ((i == j) ? &is_null : 0);
+    }
+    v.b = (int8_t)i % 2;
+    v.v1 = (int8_t)i;
+    v.v2 = (int16_t)(i * 2);
+    v.v4 = (int32_t)(i * 4);
+    v.v8 = (int64_t)(i * 8);
+    v.f4 = (float)(i * 40);
+    v.f8 = (double)(i * 80);
+    for (int j = 0; j < sizeof(v.bin) - 1; ++j) {
+      v.bin[j] = (char)(i + '0');
+    }
+
+    taos_stmt_bind_param(stmt, params);
+    taos_stmt_add_batch(stmt);
+  }
+  if (taos_stmt_execute(stmt) != 0) {
+    printf("\033[31mfailed to execute insert statement.\033[0m\n");
+    return;
+  }
+  taos_stmt_close(stmt);
+
+  // query the records
+  stmt = taos_stmt_init(taos);
+  taos_stmt_prepare(stmt, "SELECT * FROM m1 WHERE v1 > ? AND v2 < ?", 0);
+  v.v1 = 5;
+  v.v2 = 15;
+  taos_stmt_bind_param(stmt, params + 2);
+  if (taos_stmt_execute(stmt) != 0) {
+    printf("\033[31mfailed to execute select statement.\033[0m\n");
+    return;
+  }
+
+  result = taos_stmt_use_result(stmt);
+
+  TAOS_ROW    row;
+  int         rows = 0;
+  int         num_fields = taos_num_fields(result);
+  TAOS_FIELD *fields = taos_fetch_fields(result);
+  char        temp[256];
+
+  // fetch the records row by row
+  while ((row = taos_fetch_row(result))) {
+    rows++;
+    taos_print_row(temp, row, fields, num_fields);
+    printf("%s\n", temp);
+  }
+
+  taos_free_result(result);
+  taos_stmt_close(stmt);
+}
+
+void retrieve_callback(void *param, TAOS_RES *tres, int numOfRows)
+{
+  if (numOfRows > 0) {
+    printf("%d rows async retrieved\n", numOfRows);
+    taos_fetch_rows_a(tres, retrieve_callback, param);
+  } else {
+    if (numOfRows < 0) {
+      printf("\033[31masync retrieve failed, code: %d\033[0m\n", numOfRows);
+    } else {
+      printf("async retrieve completed\n");
+    }
+    taos_free_result(tres);
+  }
+}
+
+void select_callback(void *param, TAOS_RES *tres, int code)
+{
+  if (code == 0 && tres) {
+    taos_fetch_rows_a(tres, retrieve_callback, param);
+  } else {
+    printf("\033[31masync select failed, code: %d\033[0m\n", code);
+  }
+}
+
+void verify_async(TAOS* taos) {
+  prepare_data(taos);
+  taos_query_a(taos, "select * from meters", select_callback, NULL);
+  usleep(1000000);
+}
+
+void stream_callback(void *param, TAOS_RES *res, TAOS_ROW row) {
+  int         num_fields = taos_num_fields(res);
+  TAOS_FIELD* fields = taos_fetch_fields(res);
+
+  printf("got one row from stream_callback\n");
+  char temp[256];
+  taos_print_row(temp, row, fields, num_fields);
+  puts(temp);
+}
+
+void verify_stream(TAOS* taos) {
+  prepare_data(taos);
+  TAOS_STREAM* strm = taos_open_stream(
+    taos,
+    "select count(*) from meters interval(1m)",
+    stream_callback,
+    0,
+    NULL,
+    NULL);
+  printf("waiting for stream data\n"); 
+  usleep(100000);
+  taos_query(taos, "insert into t0 values(now, 0)(now+5s,1)(now+10s, 2);");
+  usleep(200000000);
+  taos_close_stream(strm);
+}
+
+int main(int argc, char *argv[]) {
+  const char* host = "127.0.0.1";
+  const char* user = "root";
+  const char* passwd = "taosdata";
+
+  taos_options(TSDB_OPTION_TIMEZONE, "GMT-8");
+  taos_init();
+
+  TAOS* taos = taos_connect(host, user, passwd, "", 0);
+  if (taos == NULL) {
+    printf("\033[31mfailed to connect to db, reason:%s\033[0m\n", taos_errstr(taos));
+    exit(1);
+  }
+
+  char* info = taos_get_server_info(taos);
+  printf("server info: %s\n", info);
+  info = taos_get_client_info(taos);
+  printf("client info: %s\n", info);
+
+  printf("************  verify query  *************\n");
+  verify_query(taos);
+
+  printf("*********  verify async query  **********\n");
+  verify_async(taos);
+
+  printf("*********** verify subscribe ************\n");
+  verify_subscribe(taos);
+
+  printf("************ verify prepare *************\n");
+  verify_prepare(taos);
+
+  printf("************ verify stream  *************\n");
+  verify_stream(taos);
+  printf("done\n");
+
+  taos_close(taos);
+  taos_cleanup();
+}
\ No newline at end of file

tests/examples/c/makefile

@@ -4,7 +4,6 @@
 ROOT=./
 TARGET=exe
 LFLAGS = '-Wl,-rpath,/usr/local/taos/driver/' -ltaos -lpthread -lm -lrt
-#LFLAGS = '-Wl,-rpath,/home/zbm/project/td/debug/build/lib/' -L/home/zbm/project/td/debug/build/lib -ltaos -lpthread -lm -lrt
 CFLAGS = -O3 -g -Wall -Wno-deprecated -fPIC -Wno-unused-result -Wconversion -Wno-char-subscripts -D_REENTRANT -Wno-format -D_REENTRANT -DLINUX -msse4.2 -Wno-unused-function -D_M_X64 \
 	-I/usr/local/taos/include -std=gnu99
 
@@ -16,6 +15,7 @@ exe:
 	gcc $(CFLAGS) ./prepare.c -o $(ROOT)/prepare $(LFLAGS)
 	gcc $(CFLAGS) ./stream.c -o $(ROOT)/stream $(LFLAGS)
 	gcc $(CFLAGS) ./subscribe.c -o $(ROOT)subscribe $(LFLAGS)
+	gcc $(CFLAGS) ./apitest.c -o $(ROOT)apitest $(LFLAGS)
 
 clean:
 	rm $(ROOT)/asyncdemo