more

src/util/inc/tarray.h

+/*
+ * 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/>.
+ */
+
+#ifndef TDENGINE_TAOSARRAY_H
+#define TDENGINE_TAOSARRAY_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "os.h"
+
+#define TARRAY_MIN_SIZE 8
+#define TARRAY_GET_ELEM(array, index) ((array)->pData + (index) * (array)->elemSize)
+
+typedef struct SArray {
+  size_t size;
+  size_t capacity;
+  size_t elemSize;
+
+  void* pData;
+} SArray;
+
+/**
+ *
+ * @param size
+ * @param elemSize
+ * @return
+ */
+void* taosArrayInit(size_t size, size_t elemSize);
+
+/**
+ *
+ * @param pArray
+ * @param pData
+ * @return
+ */
+void* taosArrayPush(SArray* pArray, void* pData);
+
+/**
+ *
+ * @param pArray
+ */
+void taosArrayPop(SArray* pArray);
+
+/**
+ *
+ * @param pArray
+ * @param index
+ * @return
+ */
+void* taosArrayGet(SArray* pArray, size_t index);
+
+/**
+ *
+ * @param pArray
+ * @return
+ */
+size_t taosArrayGetSize(SArray* pArray);
+
+/**
+ *
+ * @param pArray
+ * @param index
+ * @param pData
+ */
+void taosArrayInsert(SArray* pArray, int32_t index, void* pData);
+
+/**
+ *
+ * @param pArray
+ */
+void taosArrayDestory(SArray* pArray);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // TDENGINE_TAOSARRAY_H

src/util/inc/tskiplist.h

@@ -20,59 +20,62 @@
 extern "C" {
 #endif
 
-#define MAX_SKIP_LIST_LEVEL 20
-
-#include <pthread.h>
-#include <stdint.h>
-#include <stdlib.h>
-
 #include "os.h"
 #include "ttypes.h"
+#include "tarray.h"
 
 /*
  * key of each node
  * todo move to as the global structure in all search codes...
  */
+#define MAX_SKIP_LIST_LEVEL 15
+#define SKIP_LIST_RECORD_PERFORMANCE 0
+
+typedef char *SSkipListKey;
+typedef char *(*__sl_key_fn_t)(const void *);
+
+/**
+ * the format of skip list node is as follows:
+ * +------------+-----------------------+------------------------+-----+------+
+ * | node level | forward pointer array | backward pointer array | key | data |
+ * +------------+-----------------------+------------------------+-----+------+
+ * the skiplist node is located in a consecutive memory area, key will not be copy to skip list
+ */
+typedef struct SSkipListNode {
+  uint8_t level;
+} SSkipListNode;
 
-const static size_t SKIP_LIST_STR_KEY_LENGTH_THRESHOLD = 15;
-typedef tVariant    tSkipListKey;
-
-typedef enum tSkipListPointQueryType {
-  INCLUDE_POINT_QUERY,
-  EXCLUDE_POINT_QUERY,
-} tSkipListPointQueryType;
+#define SL_NODE_HEADER_SIZE(_l) (sizeof(SSkipListNode) + ((_l) << 1u) * POINTER_BYTES)
 
-typedef struct tSkipListNode {
-  uint16_t nLevel;
-  char *   pData;
+#define SL_GET_FORWARD_POINTER(n, _l) ((SSkipListNode **)((char *)(n) + sizeof(SSkipListNode)))[(_l)]
+#define SL_GET_BACKWARD_POINTER(n, _l) \
+  ((SSkipListNode **)((char *)(n) + sizeof(SSkipListNode) + ((n)->level) * POINTER_BYTES))[(_l)]
 
-  struct tSkipListNode **pForward;
-  struct tSkipListNode **pBackward;
+#define SL_GET_NODE_DATA(n) ((char*)(n) + SL_NODE_HEADER_SIZE((n)->level))
+#define SL_GET_NODE_KEY(s, n) ((s)->keyFn(SL_GET_NODE_DATA(n)))
 
-  tSkipListKey key;
-} tSkipListNode;
+#define SL_GET_NODE_LEVEL(n) *(int32_t *)((n))
 
 /*
- * @version 0.2
+ * @version 0.3
  * @date   2017/11/12
- * the simple version of SkipList.
+ * the simple version of skip list.
+ *
  * for multi-thread safe purpose, we employ pthread_rwlock_t to guarantee to generate
- * deterministic result. Later, we will remove the lock in SkipList to further
- * enhance the performance. In this case, one should use the concurrent skip list (by
- * using michael-scott algorithm) instead of this simple version in a multi-thread
- * environment, to achieve higher performance of read/write operations.
+ * deterministic result. Later, we will remove the lock in SkipList to further enhance the performance.
+ * In this case, one should use the concurrent skip list (by using michael-scott algorithm) instead of
+ * this simple version in a multi-thread environment, to achieve higher performance of read/write operations.
  *
  * Note: Duplicated primary key situation.
  * In case of duplicated primary key, two ways can be employed to handle this situation:
- * 1. add as normal insertion with out special process.
- * 2. add an overflow pointer at each list node, all nodes with the same key will be added
- *    in the overflow pointer. In this case, the total steps of each search will be reduced significantly.
+ * 1. add as normal insertion without special process.
+ * 2. add an overflow pointer at each list node, all nodes with the same key will be added in the overflow pointer.
+ *    In this case, the total steps of each search will be reduced significantly.
  *    Currently, we implement the skip list in a line with the first means, maybe refactor it soon.
  *
  *    Memory consumption: the memory alignment causes many memory wasted. So, employ a memory
  *    pool will significantly reduce the total memory consumption, as well as the calloc/malloc operation costs.
  *
- * 3. use the iterator pattern to refactor all routines to make it more clean
  */
 
 // state struct, record following information:
@@ -81,7 +84,7 @@ typedef struct tSkipListNode {
 // avg search rsp time, for latest 1000 queries
 // total memory size
 typedef struct tSkipListState {
-  // in bytes, sizeof(tSkipList)+sizeof(tSkipListNode)*tSkipList->nSize
+  // in bytes, sizeof(SSkipList)+sizeof(SSkipListNode)*SSkipList->nSize
   uint64_t nTotalMemSize;
   uint64_t nLevelNodeCnt[MAX_SKIP_LIST_LEVEL];
   uint64_t queryCount;  // total query count
@@ -101,68 +104,95 @@ typedef struct tSkipListState {
   uint64_t nTotalElapsedTimeForInsert;
 } tSkipListState;
 
-typedef struct tSkipList {
-  tSkipListNode pHead;
-  uint64_t      nSize;
-  uint16_t      nMaxLevel;
-  uint16_t      nLevel;
-  uint16_t      keyType;
-  uint16_t      nMaxKeyLen;
+typedef struct SSkipListKeyInfo {
+  uint8_t dupKey : 2;  // if allow duplicated key in the skip list
+  uint8_t type : 6;    // key type
+  uint8_t len;         // maximum key length, used in case of string key
+} SSkipListKeyInfo;
+
+typedef struct SSkipList {
+  __compar_fn_t    comparFn;
+  __sl_key_fn_t    keyFn;
+  uint32_t         size;
+  uint8_t          maxLevel;
+  uint8_t          level;
+  SSkipListKeyInfo keyInfo;
+
+  pthread_rwlock_t *lock;
+  SSkipListNode *   pHead;
+
+#if SKIP_LIST_RECORD_PERFORMANCE
+  tSkipListState state;  // skiplist state
+#endif
 
-  __compar_fn_t    comparator;
-  pthread_rwlock_t lock;   // will be removed soon
-  tSkipListState   state;  // skiplist state
-} tSkipList;
+} SSkipList;
 
 /*
  * iterate the skiplist
  * this will cause the multi-thread problem, when the skiplist is destroyed, the iterate may
  * continue iterating the skiplist, so add the reference count for skiplist
- * TODO add the ref for skiplist when one iterator is created
+ * TODO add the ref for skip list when one iterator is created
  */
 typedef struct SSkipListIterator {
-  tSkipList *    pSkipList;
-  tSkipListNode *cur;
+  SSkipList *    pSkipList;
+  SSkipListNode *cur;
   int64_t        num;
 } SSkipListIterator;
 
-/*
- * query condition structure to denote the range query
- * todo merge the point query cond with range query condition
+/**
+ *
+ * @param nMaxLevel   maximum skip list level
+ * @param keyType     type of key
+ * @param dupKey      allow the duplicated key in the skip list
+ * @return
  */
-typedef struct tSKipListQueryCond {
-  // when the upper bounding == lower bounding, it is a point query
-  tSkipListKey lowerBnd;
-  tSkipListKey upperBnd;
-  int32_t      lowerBndRelOptr;  // relation operator to denote if lower bound is
-  int32_t      upperBndRelOptr;  // included or not
-} tSKipListQueryCond;
-
-tSkipList *tSkipListCreate(int16_t nMaxLevel, int16_t keyType, int16_t nMaxKeyLen);
-
-void *tSkipListDestroy(tSkipList *pSkipList);
-
-// create skip list key
-tSkipListKey tSkipListCreateKey(int32_t type, char *val, size_t keyLength);
+SSkipList *tSkipListCreate(uint8_t nMaxLevel, uint8_t keyType, uint8_t keyLen, uint8_t dupKey, uint8_t threadsafe,
+                           __sl_key_fn_t fn);
 
-// destroy skip list key
-void tSkipListDestroyKey(tSkipListKey *pKey);
+/**
+ *
+ * @param pSkipList
+ * @return                NULL will always be returned
+ */
+void *tSkipListDestroy(SSkipList *pSkipList);
 
-// put data into skiplist
-tSkipListNode *tSkipListPut(tSkipList *pSkipList, void *pData, tSkipListKey *pKey, int32_t insertIdenticalKey);
+/**
+ *
+ * @param pSkipList
+ * @param level
+ * @param headSize
+ */
+void tSkipListRandNodeInfo(SSkipList *pSkipList, int32_t *level, int32_t *headSize);
 
-/*
- * get only *one* node of which key is equalled to pKey, even there are more
- * than one nodes are of the same key
+/**
+ * put the skip list node into the skip list.
+ * If failed, NULL will be returned, otherwise, the pNode will be returned.
+ *
+ * @param pSkipList
+ * @param pNode
+ * @return
  */
-tSkipListNode *tSkipListGetOne(tSkipList *pSkipList, tSkipListKey *pKey);
+SSkipListNode *tSkipListPut(SSkipList *pSkipList, SSkipListNode *pNode);
 
-/*
- * get all data with the same keys
+/**
+ * get only *one* node of which key is equalled to pKey, even there are more than one nodes are of the same key
+ *
+ * @param pSkipList
+ * @param pKey
+ * @param keyType
+ * @return
  */
-int32_t tSkipListGets(tSkipList *pSkipList, tSkipListKey *pKey, tSkipListNode ***pRes);
+SArray* tSkipListGet(SSkipList *pSkipList, SSkipListKey pKey, int16_t keyType);
 
-int32_t tSkipListIterateList(tSkipList *pSkipList, tSkipListNode ***pRes, bool (*fp)(tSkipListNode *, void *),
+/**
+ *
+ * @param pSkipList
+ * @param pRes
+ * @param fp
+ * @param param
+ * @return
+ */
+int32_t tSkipListIterateList(SSkipList *pSkipList, SSkipListNode ***pRes, bool (*fp)(SSkipListNode *, void *),
                              void *param);
 
 /*
@@ -173,30 +203,16 @@ int32_t tSkipListIterateList(tSkipList *pSkipList, tSkipListNode ***pRes, bool (
  * true: one node has been removed
  * false: no node has been removed
  */
-bool tSkipListRemove(tSkipList *pSkipList, tSkipListKey *pKey);
+bool tSkipListRemove(SSkipList *pSkipList, SSkipListKey *pKey);
 
 /*
  * remove the specified node in parameters
  */
-void tSkipListRemoveNode(tSkipList *pSkipList, tSkipListNode *pNode);
-
-// for debug purpose only
-void tSkipListPrint(tSkipList *pSkipList, int16_t nlevel);
-
-/*
- * range query & single point query function
- */
-int32_t tSkipListQuery(tSkipList *pSkipList, tSKipListQueryCond *pQueryCond, tSkipListNode ***pResult);
-
-/*
- * include/exclude point query
- */
-int32_t tSkipListPointQuery(tSkipList *pSkipList, tSkipListKey *pKey, int32_t numOfKey, tSkipListPointQueryType type,
-                            tSkipListNode ***pResult);
+void tSkipListRemoveNode(SSkipList *pSkipList, SSkipListNode *pNode);
 
-int32_t tSkipListIteratorReset(tSkipList *pSkipList, SSkipListIterator *iter);
-bool tSkipListIteratorNext(SSkipListIterator *iter);
-tSkipListNode *tSkipListIteratorGet(SSkipListIterator *iter);
+int32_t        tSkipListIteratorReset(SSkipList *pSkipList, SSkipListIterator *iter);
+bool           tSkipListIteratorNext(SSkipListIterator *iter);
+SSkipListNode *tSkipListIteratorGet(SSkipListIterator *iter);
 
 #ifdef __cplusplus
 }

src/util/src/tarray.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 "tarray.h"
+
+void* taosArrayInit(size_t size, size_t elemSize) {
+  assert(elemSize > 0);
+
+  if (size < TARRAY_MIN_SIZE) {
+    size = TARRAY_MIN_SIZE;
+  }
+
+  SArray* pArray = calloc(1, sizeof(SArray));
+  if (pArray == NULL) {
+    return NULL;
+  }
+
+  pArray->pData = calloc(size, elemSize * size);
+  if (pArray->pData == NULL) {
+    free(pArray);
+    return NULL;
+  }
+
+  pArray->capacity = size;
+  pArray->elemSize = elemSize;
+  return pArray;
+}
+
+static void taosArrayResize(SArray* pArray) {
+  assert(pArray->size >= pArray->capacity);
+
+  size_t size = pArray->capacity;
+  size = (size << 1u);
+
+  void* tmp = realloc(pArray->pData, size * pArray->elemSize);
+  if (tmp == NULL) {
+    // todo
+  }
+
+  pArray->pData = tmp;
+  pArray->capacity = size;
+}
+
+void* taosArrayPush(SArray* pArray, void* pData) {
+  if (pArray == NULL || pData == NULL) {
+    return NULL;
+  }
+
+  if (pArray->size >= pArray->capacity) {
+    taosArrayResize(pArray);
+  }
+
+  void* dst = TARRAY_GET_ELEM(pArray, pArray->size);
+  memcpy(dst, pData, pArray->elemSize);
+
+  pArray->size += 1;
+  return dst;
+}
+
+void taosArrayPop(SArray* pArray) {
+  if (pArray == NULL || pArray->size == 0) {
+    return;
+  }
+
+  pArray->size -= 1;
+}
+
+void* taosArrayGet(SArray* pArray, size_t index) {
+  assert(index < pArray->size);
+  return TARRAY_GET_ELEM(pArray, index);
+}
+
+size_t taosArrayGetSize(SArray* pArray) { return pArray->size; }
+
+void taosArrayInsert(SArray* pArray, int32_t index, void* pData) {
+  if (pArray == NULL || pData == NULL) {
+    return;
+  }
+
+  if (index >= pArray->size) {
+    taosArrayPush(pArray, pData);
+    return;
+  }
+
+  if (pArray->size >= pArray->capacity) {
+    taosArrayResize(pArray);
+  }
+
+  void* dst = TARRAY_GET_ELEM(pArray, index);
+
+  int32_t remain = pArray->size - index;
+  memmove(dst + pArray->elemSize, dst, pArray->elemSize * remain);
+  memcpy(dst, pData, pArray->elemSize);
+
+  pArray->size += 1;
+}
+
+void taosArrayDestory(SArray* pArray) {
+  if (pArray == NULL) {
+    return;
+  }
+
+  free(pArray->pData);
+  free(pArray);
+}

src/util/src/tskiplist.c

@@ -15,49 +15,54 @@
 #include "os.h"
 
 #include "tlog.h"
-#include "taosdef.h"
+// #include "tsdb.h"
 #include "tskiplist.h"
 #include "tutil.h"
 
-static FORCE_INLINE void recordNodeEachLevel(tSkipList *pSkipList, int32_t nLevel) {  // record link count in each level
-  for (int32_t i = 0; i < nLevel; ++i) {
+static FORCE_INLINE void recordNodeEachLevel(SSkipList *pSkipList, int32_t level) {  // record link count in each level
+#if SKIP_LIST_RECORD_PERFORMANCE
+  for (int32_t i = 0; i < level; ++i) {
     pSkipList->state.nLevelNodeCnt[i]++;
   }
+#endif
 }
 
-static FORCE_INLINE void removeNodeEachLevel(tSkipList *pSkipList, int32_t nLevel) {
-  for (int32_t i = 0; i < nLevel; ++i) {
+static FORCE_INLINE void removeNodeEachLevel(SSkipList *pSkipList, int32_t level) {
+#if SKIP_LIST_RECORD_PERFORMANCE
+  for (int32_t i = 0; i < level; ++i) {
     pSkipList->state.nLevelNodeCnt[i]--;
   }
+#endif
 }
 
-static FORCE_INLINE int32_t getSkipListNodeRandomHeight(tSkipList *pSkipList) {
+static FORCE_INLINE int32_t getSkipListNodeRandomHeight(SSkipList *pSkipList) {
   const uint32_t factor = 4;
 
   int32_t n = 1;
-  while ((rand() % factor) == 0 && n <= pSkipList->nMaxLevel) {
+  while ((rand() % factor) == 0 && n <= pSkipList->maxLevel) {
     n++;
   }
 
   return n;
 }
 
-static FORCE_INLINE int32_t getSkipListNodeLevel(tSkipList *pSkipList) {
-  int32_t nLevel = getSkipListNodeRandomHeight(pSkipList);
-  if (pSkipList->nSize == 0) {
-    nLevel = 1;
-    pSkipList->nLevel = 1;
+static FORCE_INLINE int32_t getSkipListRandLevel(SSkipList *pSkipList) {
+  int32_t level = getSkipListNodeRandomHeight(pSkipList);
+  if (pSkipList->size == 0) {
+    level = 1;
+    pSkipList->level = 1;
   } else {
-    if (nLevel > pSkipList->nLevel && pSkipList->nLevel < pSkipList->nMaxLevel) {
-      nLevel = (++pSkipList->nLevel);
+    if (level > pSkipList->level && pSkipList->level < pSkipList->maxLevel) {
+      level = (++pSkipList->level);
     }
   }
-  return nLevel;
+  return level;
 }
 
-void tSkipListDoInsert(tSkipList *pSkipList, tSkipListNode **forward, int32_t nLevel, tSkipListNode *pNode);
+static void tSkipListDoInsert(SSkipList *pSkipList, SSkipListNode **forward, int32_t level, SSkipListNode *pNode);
 
-void tSkipListDoRecordPut(tSkipList *pSkipList) {
+void tSkipListDoRecordPut(SSkipList *pSkipList) {
+#if SKIP_LIST_RECORD_PERFORMANCE
   const int32_t MAX_RECORD_NUM = 1000;
 
   if (pSkipList->state.nInsertObjs == MAX_RECORD_NUM) {
@@ -67,61 +72,38 @@ void tSkipListDoRecordPut(tSkipList *pSkipList) {
   } else {
     pSkipList->state.nInsertObjs++;
   }
+#endif
 }
 
-int32_t compareIntVal(const void *pLeft, const void *pRight) {
-  int64_t lhs = ((tSkipListKey *)pLeft)->i64Key;
-  int64_t rhs = ((tSkipListKey *)pRight)->i64Key;
-
-  DEFAULT_COMP(lhs, rhs);
-}
-
-int32_t compareIntDoubleVal(const void *pLeft, const void *pRight) {
-  int64_t lhs = ((tSkipListKey *)pLeft)->i64Key;
-  double  rhs = ((tSkipListKey *)pRight)->dKey;
-  if (fabs(lhs - rhs) < FLT_EPSILON) {
+int32_t compareInt32Val(const void *pLeft, const void *pRight) {
+  int32_t ret = GET_INT32_VAL(pLeft) - GET_INT32_VAL(pRight);
+  if (ret == 0) {
     return 0;
   } else {
-    return (lhs > rhs) ? 1 : -1;
+    return ret > 0 ? 1 : -1;
   }
 }
 
-int32_t compareDoubleIntVal(const void *pLeft, const void *pRight) {
-  double  lhs = ((tSkipListKey *)pLeft)->dKey;
-  int64_t rhs = ((tSkipListKey *)pRight)->i64Key;
-  if (fabs(lhs - rhs) < FLT_EPSILON) {
+int32_t compareInt64Val(const void *pLeft, const void *pRight) {
+  int32_t ret = GET_INT64_VAL(pLeft) - GET_INT64_VAL(pRight);
+  if (ret == 0) {
     return 0;
   } else {
-    return (lhs > rhs) ? 1 : -1;
+    return ret > 0 ? 1 : -1;
   }
 }
 
-int32_t compareDoubleVal(const void *pLeft, const void *pRight) {
-  double ret = (((tSkipListKey *)pLeft)->dKey - ((tSkipListKey *)pRight)->dKey);
-  if (fabs(ret) < FLT_EPSILON) {
+int32_t compareInt16Val(const void *pLeft, const void *pRight) {
+  int32_t ret = GET_INT16_VAL(pLeft) - GET_INT16_VAL(pRight);
+  if (ret == 0) {
     return 0;
   } else {
     return ret > 0 ? 1 : -1;
   }
 }
 
-int32_t compareStrVal(const void *pLeft, const void *pRight) {
-  tSkipListKey *pL = (tSkipListKey *)pLeft;
-  tSkipListKey *pR = (tSkipListKey *)pRight;
-
-  if (pL->nLen == 0 && pR->nLen == 0) {
-    return 0;
-  }
-
-  //handle only one-side bound compare situation, there is only lower bound or only upper bound
-  if (pL->nLen == -1) {
-    return 1;  // no lower bound, lower bound is minimum, always return -1;
-  } else if (pR->nLen == -1) {
-    return -1;  // no upper bound, upper bound is maximum situation, always return 1;
-  }
-
-  int32_t ret = strcmp(((tSkipListKey *)pLeft)->pz, ((tSkipListKey *)pRight)->pz);
-
+int32_t compareInt8Val(const void *pLeft, const void *pRight) {
+  int32_t ret = GET_INT8_VAL(pLeft) - GET_INT8_VAL(pRight);
   if (ret == 0) {
     return 0;
   } else {
@@ -129,716 +111,692 @@ int32_t compareStrVal(const void *pLeft, const void *pRight) {
   }
 }
 
-int32_t compareWStrVal(const void *pLeft, const void *pRight) {
-  tSkipListKey *pL = (tSkipListKey *)pLeft;
-  tSkipListKey *pR = (tSkipListKey *)pRight;
-
-  if (pL->nLen == 0 && pR->nLen == 0) {
-    return 0;
-  }
-
-  //handle only one-side bound compare situation, there is only lower bound or only upper bound
-  if (pL->nLen == -1) {
-    return 1;  // no lower bound, lower bound is minimum, always return -1;
-  } else if (pR->nLen == -1) {
-    return -1;  // no upper bound, upper bound is maximum situation, always return 1;
-  }
+int32_t compareIntDoubleVal(const void *pLeft, const void *pRight) {
+  //  int64_t lhs = ((SSkipListKey *)pLeft)->i64Key;
+  //  double  rhs = ((SSkipListKey *)pRight)->dKey;
+  //  if (fabs(lhs - rhs) < FLT_EPSILON) {
+  //    return 0;
+  //  } else {
+  //    return (lhs > rhs) ? 1 : -1;
+  //  }
+  return 0;
+}
 
-  int32_t ret = wcscmp(((tSkipListKey *)pLeft)->wpz, ((tSkipListKey *)pRight)->wpz);
+int32_t compareDoubleIntVal(const void *pLeft, const void *pRight) {
+  //  double  lhs = ((SSkipListKey *)pLeft)->dKey;
+  //  int64_t rhs = ((SSkipListKey *)pRight)->i64Key;
+  //  if (fabs(lhs - rhs) < FLT_EPSILON) {
+  //    return 0;
+  //  } else {
+  //    return (lhs > rhs) ? 1 : -1;
+  //  }
+  return 0;
+}
 
-  if (ret == 0) {
+int32_t compareDoubleVal(const void *pLeft, const void *pRight) {
+  double ret = GET_DOUBLE_VAL(pLeft) - GET_DOUBLE_VAL(pRight);
+  if (fabs(ret) < FLT_EPSILON) {
     return 0;
   } else {
     return ret > 0 ? 1 : -1;
   }
 }
 
-static __compar_fn_t getKeyFilterComparator(tSkipList *pSkipList, int32_t filterDataType) {
-  __compar_fn_t comparator = NULL;
+int32_t compareStrVal(const void *pLeft, const void *pRight) {
+  //  SSkipListKey *pL = (SSkipListKey *)pLeft;
+  //  SSkipListKey *pR = (SSkipListKey *)pRight;
+  //
+  //  if (pL->nLen == 0 && pR->nLen == 0) {
+  //    return 0;
+  //  }
+  //
+  //  // handle only one-side bound compare situation, there is only lower bound or only upper bound
+  //  if (pL->nLen == -1) {
+  //    return 1;  // no lower bound, lower bound is minimum, always return -1;
+  //  } else if (pR->nLen == -1) {
+  //    return -1;  // no upper bound, upper bound is maximum situation, always return 1;
+  //  }
+  //
+  //  int32_t ret = strcmp(((SSkipListKey *)pLeft)->pz, ((SSkipListKey *)pRight)->pz);
+  //
+  //  if (ret == 0) {
+  //    return 0;
+  //  } else {
+  //    return ret > 0 ? 1 : -1;
+  //  }
+  return 0;
+}
 
-  switch (pSkipList->keyType) {
+int32_t compareWStrVal(const void *pLeft, const void *pRight) {
+  //  SSkipListKey *pL = (SSkipListKey *)pLeft;
+  //  SSkipListKey *pR = (SSkipListKey *)pRight;
+  //
+  //  if (pL->nLen == 0 && pR->nLen == 0) {
+  //    return 0;
+  //  }
+  //
+  //  // handle only one-side bound compare situation, there is only lower bound or only upper bound
+  //  if (pL->nLen == -1) {
+  //    return 1;  // no lower bound, lower bound is minimum, always return -1;
+  //  } else if (pR->nLen == -1) {
+  //    return -1;  // no upper bound, upper bound is maximum situation, always return 1;
+  //  }
+  //
+  //  int32_t ret = wcscmp(((SSkipListKey *)pLeft)->wpz, ((SSkipListKey *)pRight)->wpz);
+  //
+  //  if (ret == 0) {
+  //    return 0;
+  //  } else {
+  //    return ret > 0 ? 1 : -1;
+  //  }
+  return 0;
+}
+
+static __compar_fn_t getKeyFilterComparator(SSkipList *pSkipList, int32_t filterDataType) {
+  __compar_fn_t comparFn = NULL;
+
+  switch (pSkipList->keyInfo.type) {
     case TSDB_DATA_TYPE_TINYINT:
     case TSDB_DATA_TYPE_SMALLINT:
     case TSDB_DATA_TYPE_INT:
-    case TSDB_DATA_TYPE_BIGINT:
+    case TSDB_DATA_TYPE_BIGINT: {
+      if (filterDataType == TSDB_DATA_TYPE_BIGINT) {
+        comparFn = compareInt64Val;
+        break;
+      }
+    }
     case TSDB_DATA_TYPE_BOOL: {
       if (filterDataType >= TSDB_DATA_TYPE_BOOL && filterDataType <= TSDB_DATA_TYPE_BIGINT) {
-        comparator = compareIntVal;
+        comparFn = compareInt32Val;
       } else if (filterDataType >= TSDB_DATA_TYPE_FLOAT && filterDataType <= TSDB_DATA_TYPE_DOUBLE) {
-        comparator = compareIntDoubleVal;
+        comparFn = compareIntDoubleVal;
       }
       break;
     }
     case TSDB_DATA_TYPE_FLOAT:
     case TSDB_DATA_TYPE_DOUBLE: {
-      if (filterDataType >= TSDB_DATA_TYPE_BOOL && filterDataType <= TSDB_DATA_TYPE_BIGINT) {
-        comparator = compareDoubleIntVal;
-      } else if (filterDataType >= TSDB_DATA_TYPE_FLOAT && filterDataType <= TSDB_DATA_TYPE_DOUBLE) {
-        comparator = compareDoubleVal;
+//      if (filterDataType >= TSDB_DATA_TYPE_BOOL && filterDataType <= TSDB_DATA_TYPE_BIGINT) {
+//        comparFn = compareDoubleIntVal;
+//      } else if (filterDataType >= TSDB_DATA_TYPE_FLOAT && filterDataType <= TSDB_DATA_TYPE_DOUBLE) {
+//        comparFn = compareDoubleVal;
+//      }
+      if (filterDataType == TSDB_DATA_TYPE_DOUBLE) {
+        comparFn = compareDoubleVal;
       }
       break;
     }
     case TSDB_DATA_TYPE_BINARY:
-      comparator = compareStrVal;
+      comparFn = compareStrVal;
       break;
     case TSDB_DATA_TYPE_NCHAR:
-      comparator = compareWStrVal;
+      comparFn = compareWStrVal;
       break;
     default:
-      comparator = compareIntVal;
+      comparFn = compareInt32Val;
       break;
   }
 
-  return comparator;
+  return comparFn;
 }
 
 static __compar_fn_t getKeyComparator(int32_t keyType) {
-  __compar_fn_t comparator = NULL;
+  __compar_fn_t comparFn = NULL;
 
   switch (keyType) {
     case TSDB_DATA_TYPE_TINYINT:
+      comparFn = compareInt8Val;
+      break;
     case TSDB_DATA_TYPE_SMALLINT:
+      comparFn = compareInt16Val;
+      break;
     case TSDB_DATA_TYPE_INT:
+      comparFn = compareInt32Val;
+      break;
     case TSDB_DATA_TYPE_BIGINT:
+      comparFn = compareInt64Val;
+      break;
     case TSDB_DATA_TYPE_BOOL:
-      comparator = compareIntVal;
+      comparFn = compareInt32Val;
       break;
 
     case TSDB_DATA_TYPE_FLOAT:
     case TSDB_DATA_TYPE_DOUBLE:
-      comparator = compareDoubleVal;
+      comparFn = compareDoubleVal;
       break;
 
     case TSDB_DATA_TYPE_BINARY:
-      comparator = compareStrVal;
+      comparFn = compareStrVal;
       break;
 
     case TSDB_DATA_TYPE_NCHAR:
-      comparator = compareWStrVal;
+      comparFn = compareWStrVal;
       break;
 
     default:
-      comparator = compareIntVal;
+      comparFn = compareInt32Val;
       break;
   }
 
-  return comparator;
+  return comparFn;
 }
 
-tSkipList* tSkipListCreate(int16_t nMaxLevel, int16_t keyType, int16_t nMaxKeyLen) {
-  tSkipList *pSkipList = (tSkipList *)calloc(1, sizeof(tSkipList));
+SSkipList *tSkipListCreate(uint8_t maxLevel, uint8_t keyType, uint8_t keyLen, uint8_t dupKey, uint8_t lock,
+                           __sl_key_fn_t fn) {
+  SSkipList *pSkipList = (SSkipList *)calloc(1, sizeof(SSkipList));
   if (pSkipList == NULL) {
     return NULL;
   }
 
-  pSkipList->keyType = keyType;
-
-  pSkipList->comparator = getKeyComparator(keyType);
-  pSkipList->pHead.pForward = (tSkipListNode **)calloc(1, POINTER_BYTES * MAX_SKIP_LIST_LEVEL);
-
-  pSkipList->nMaxLevel = MAX_SKIP_LIST_LEVEL;
-  pSkipList->nLevel = 1;
+  if (maxLevel > MAX_SKIP_LIST_LEVEL) {
+    maxLevel = MAX_SKIP_LIST_LEVEL;
+  }
 
-  pSkipList->nMaxKeyLen = nMaxKeyLen;
-  pSkipList->nMaxLevel = nMaxLevel;
+  pSkipList->keyInfo = (SSkipListKeyInfo){.type = keyType, .len = keyLen, .dupKey = dupKey};
+  pSkipList->keyFn = fn;
 
-  if (pthread_rwlock_init(&pSkipList->lock, NULL) != 0) {
-    tfree(pSkipList->pHead.pForward);
-    tfree(pSkipList);
-    return NULL;
-  }
+  pSkipList->comparFn = getKeyComparator(keyType);
+  pSkipList->maxLevel = maxLevel;
+  pSkipList->level = 1;
 
-  srand(time(NULL));
-  pSkipList->state.nTotalMemSize += sizeof(tSkipList);
-  return pSkipList;
-}
+  pSkipList->pHead = (SSkipListNode *)calloc(1, SL_NODE_HEADER_SIZE(maxLevel));
+  pSkipList->pHead->level = pSkipList->maxLevel;
 
-static void doRemove(tSkipList *pSkipList, tSkipListNode *pNode, tSkipListNode *forward[]) {
-  int32_t level = pNode->nLevel;
-  for (int32_t j = level - 1; j >= 0; --j) {
-    if ((forward[j]->pForward[j] != NULL) && (forward[j]->pForward[j]->pForward[j])) {
-      forward[j]->pForward[j]->pForward[j]->pBackward[j] = forward[j];
-    }
+  if (lock) {
+    pSkipList->lock = calloc(1, sizeof(pthread_rwlock_t));
 
-    if (forward[j]->pForward[j] != NULL) {
-      forward[j]->pForward[j] = forward[j]->pForward[j]->pForward[j];
+    if (pthread_rwlock_init(pSkipList->lock, NULL) != 0) {
+      tfree(pSkipList->pHead);
+      tfree(pSkipList);
+      return NULL;
     }
   }
 
-  pSkipList->state.nTotalMemSize -= (sizeof(tSkipListNode) + POINTER_BYTES * pNode->nLevel * 2);
-  removeNodeEachLevel(pSkipList, pNode->nLevel);
+  srand(time(NULL));
+
+#if SKIP_LIST_RECORD_PERFORMANCE
+  pSkipList->state.nTotalMemSize += sizeof(SSkipList);
+#endif
 
-  tfree(pNode);
-  --pSkipList->nSize;
+  return pSkipList;
 }
 
-static size_t getOneNodeSize(const tSkipListKey *pKey, int32_t nLevel) {
-  size_t size = sizeof(tSkipListNode) + sizeof(intptr_t) * (nLevel << 1);
-  if (pKey->nType == TSDB_DATA_TYPE_BINARY) {
-    size += pKey->nLen + 1;
-  } else if (pKey->nType == TSDB_DATA_TYPE_NCHAR) {
-    size += (pKey->nLen + 1) * TSDB_NCHAR_SIZE;
+// static void doRemove(SSkipList *pSkipList, SSkipListNode *pNode, SSkipListNode *forward[]) {
+//  int32_t level = pNode->level;
+//  for (int32_t j = level - 1; j >= 0; --j) {
+//    if ((forward[j]->pForward[j] != NULL) && (forward[j]->pForward[j]->pForward[j])) {
+//      forward[j]->pForward[j]->pForward[j]->pBackward[j] = forward[j];
+//    }
+//
+//    if (forward[j]->pForward[j] != NULL) {
+//      forward[j]->pForward[j] = forward[j]->pForward[j]->pForward[j];
+//    }
+//  }
+//
+//  pSkipList->state.nTotalMemSize -= (sizeof(SSkipListNode) + POINTER_BYTES * pNode->level * 2);
+//  removeNodeEachLevel(pSkipList, pNode->level);
+//
+//  tfree(pNode);
+//  --pSkipList->size;
+//}
+
+void *tSkipListDestroy(SSkipList *pSkipList) {
+  if (pSkipList == NULL) {
+    return NULL;
   }
 
-  return size;
-}
+  if (pSkipList->lock) {
+    pthread_rwlock_wrlock(pSkipList->lock);
+  }
 
-static tSkipListNode *tSkipListCreateNode(void *pData, const tSkipListKey *pKey, int32_t nLevel) {
-  size_t         nodeSize = getOneNodeSize(pKey, nLevel);
-  tSkipListNode *pNode = (tSkipListNode *)calloc(1, nodeSize);
+  SSkipListNode *pNode = SL_GET_FORWARD_POINTER(pSkipList->pHead, 0);  // pSkipList->pHead.pForward[0];
 
-  pNode->pForward = (tSkipListNode **)(&pNode[1]);
-  pNode->pBackward = (pNode->pForward + nLevel);
+  while (pNode) {
+    SSkipListNode *pTemp = pNode;
+    pNode = SL_GET_FORWARD_POINTER(pNode, 0);
+    tfree(pTemp);
+  }
 
-  pNode->pData = pData;
+  tfree(pSkipList->pHead);
 
-  pNode->key = *pKey;
-  if (pKey->nType == TSDB_DATA_TYPE_BINARY) {
-    pNode->key.pz = (char *)(pNode->pBackward + nLevel);
+  if (pSkipList->lock) {
+    pthread_rwlock_unlock(pSkipList->lock);
+    pthread_rwlock_destroy(pSkipList->lock);
 
-    strcpy(pNode->key.pz, pKey->pz);
-    pNode->key.pz[pKey->nLen] = 0;
-  } else if (pKey->nType == TSDB_DATA_TYPE_NCHAR) {
-    pNode->key.wpz = (wchar_t *)(pNode->pBackward + nLevel);
-    wcsncpy(pNode->key.wpz, pKey->wpz, pKey->nLen);
-    pNode->key.wpz[pKey->nLen] = 0;
+    tfree(pSkipList->lock);
   }
 
-  pNode->nLevel = nLevel;
-  return pNode;
-}
-
-tSkipListKey tSkipListCreateKey(int32_t type, char *val, size_t keyLength) {
-  tSkipListKey k = {0};
-  tVariantCreateFromBinary(&k, val, (uint32_t) keyLength, (uint32_t) type);
-  return k;
+  tfree(pSkipList->pHead);
+  tfree(pSkipList);
+  return NULL;
 }
 
-void tSkipListDestroyKey(tSkipListKey *pKey) { tVariantDestroy(pKey); }
-
-void* tSkipListDestroy(tSkipList *pSkipList) {
+void tSkipListRandNodeInfo(SSkipList *pSkipList, int32_t *level, int32_t *headSize) {
   if (pSkipList == NULL) {
-    return NULL;
-  }
-
-  pthread_rwlock_wrlock(&pSkipList->lock);
-  tSkipListNode *pNode = pSkipList->pHead.pForward[0];
-  while (pNode) {
-    tSkipListNode *pTemp = pNode;
-    pNode = pNode->pForward[0];
-    tfree(pTemp);
+    return;
   }
 
-  tfree(pSkipList->pHead.pForward);
-  pthread_rwlock_unlock(&pSkipList->lock);
-
-  pthread_rwlock_destroy(&pSkipList->lock);
-  tfree(pSkipList);
-
-  return NULL;
+  *level = getSkipListRandLevel(pSkipList);
+  *headSize = SL_NODE_HEADER_SIZE(*level);
 }
 
-tSkipListNode *tSkipListPut(tSkipList *pSkipList, void *pData, tSkipListKey *pKey, int32_t insertIdenticalKey) {
+SSkipListNode *tSkipListPut(SSkipList *pSkipList, SSkipListNode *pNode) {
   if (pSkipList == NULL) {
     return NULL;
   }
 
-  pthread_rwlock_wrlock(&pSkipList->lock);
+  if (pSkipList->lock) {
+    pthread_rwlock_wrlock(pSkipList->lock);
+  }
 
   // record one node is put into skiplist
   tSkipListDoRecordPut(pSkipList);
 
-  tSkipListNode *px = &pSkipList->pHead;
+  SSkipListNode *px = pSkipList->pHead;
+  SSkipListNode *forward[MAX_SKIP_LIST_LEVEL] = {0};
 
-  tSkipListNode *forward[MAX_SKIP_LIST_LEVEL] = {0};
-  for (int32_t i = pSkipList->nLevel - 1; i >= 0; --i) {
-    while (px->pForward[i] != NULL && (pSkipList->comparator(&px->pForward[i]->key, pKey) < 0)) {
-      px = px->pForward[i];
+  for (int32_t i = pSkipList->level - 1; i >= 0; --i) {
+    SSkipListNode *p = SL_GET_FORWARD_POINTER(px, i);
+    while (p != NULL) {
+      char *key = SL_GET_NODE_KEY(pSkipList, p);
+      char *newDatakey = SL_GET_NODE_KEY(pSkipList, pNode);
+
+      // if the forward element is less than the specified key, forward one step
+      if (pSkipList->comparFn(key, newDatakey) < 0) {
+        px = p;
+
+        p = SL_GET_FORWARD_POINTER(px, i);
+      } else {
+        break;
+      }
     }
 
+#if SKIP_LIST_RECORD_PERFORMANCE
     pSkipList->state.nTotalStepsForInsert++;
+#endif
     forward[i] = px;
   }
 
-  // if the skiplist does not allowed identical key inserted, the new data will be discarded.
-  if ((insertIdenticalKey == 0) && forward[0] != &pSkipList->pHead &&
-      (pSkipList->comparator(&forward[0]->key, pKey) == 0)) {
-    pthread_rwlock_unlock(&pSkipList->lock);
-    return forward[0];
+  // if the skip list does not allowed identical key inserted, the new data will be discarded.
+  if (pSkipList->keyInfo.dupKey == 0 && forward[0] != pSkipList->pHead) {
+    char *key = SL_GET_NODE_KEY(pSkipList, forward[0]);
+    char *pNewDataKey = SL_GET_NODE_KEY(pSkipList, pNode);
+
+    if (pSkipList->comparFn(key, pNewDataKey) == 0) {
+      if (pSkipList->lock) {
+        pthread_rwlock_unlock(pSkipList->lock);
+      }
+
+      return forward[0];
+    }
   }
 
-  int32_t nLevel = getSkipListNodeLevel(pSkipList);
-  recordNodeEachLevel(pSkipList, nLevel);
+#if SKIP_LIST_RECORD_PERFORMANCE
+  recordNodeEachLevel(pSkipList, level);
+#endif
 
-  tSkipListNode *pNode = tSkipListCreateNode(pData, pKey, nLevel);
-  tSkipListDoInsert(pSkipList, forward, nLevel, pNode);
+  int32_t level = SL_GET_NODE_LEVEL(pNode);
+  tSkipListDoInsert(pSkipList, forward, level, pNode);
 
-  pSkipList->nSize += 1;
+  atomic_add_fetch_32(&pSkipList->size, 1);
 
-  //    char tmpstr[512] = {0};
-  //    tVariantToString(&pNode->key, tmpstr);
-  //    pTrace("skiplist:%p, node added, key:%s, total list len:%d", pSkipList,
-  //    tmpstr, pSkipList->nSize);
+#if SKIP_LIST_RECORD_PERFORMANCE
+  pSkipList->state.nTotalMemSize += getOneNodeSize(pKey, level);
+#endif
 
-  pSkipList->state.nTotalMemSize += getOneNodeSize(pKey, nLevel);
-  pthread_rwlock_unlock(&pSkipList->lock);
+  if (pSkipList->lock) {
+    pthread_rwlock_unlock(pSkipList->lock);
+  }
 
   return pNode;
 }
 
-void tSkipListDoInsert(tSkipList *pSkipList, tSkipListNode **forward, int32_t nLevel, tSkipListNode *pNode) {
-  for (int32_t i = 0; i < nLevel; ++i) {
-    tSkipListNode *x = forward[i];
+void tSkipListDoInsert(SSkipList *pSkipList, SSkipListNode **forward, int32_t level, SSkipListNode *pNode) {
+  for (int32_t i = 0; i < level; ++i) {
+    SSkipListNode *x = forward[i];
     if (x != NULL) {
-      pNode->pBackward[i] = x;
-      if (x->pForward[i]) x->pForward[i]->pBackward[i] = pNode;
+      SL_GET_BACKWARD_POINTER(pNode, i) = x;
 
-      pNode->pForward[i] = x->pForward[i];
-      x->pForward[i] = pNode;
+      SSkipListNode *pForward = SL_GET_FORWARD_POINTER(x, i);
+      if (pForward) {
+        SL_GET_BACKWARD_POINTER(pForward, i) = pNode;
+      }
+
+      SL_GET_FORWARD_POINTER(pNode, i) = SL_GET_FORWARD_POINTER(x, i);
+      SL_GET_FORWARD_POINTER(x, i) = pNode;
     } else {
-      pSkipList->pHead.pForward[i] = pNode;
-      pNode->pBackward[i] = &(pSkipList->pHead);
+      SL_GET_FORWARD_POINTER(pSkipList->pHead, i) = pNode;
+      SL_GET_BACKWARD_POINTER(pSkipList->pHead, i) = (pSkipList->pHead);
     }
   }
 }
 
-tSkipListNode *tSkipListGetOne(tSkipList *pSkipList, tSkipListKey *pKey) {
-  int32_t sLevel = pSkipList->nLevel - 1;
+SArray* tSkipListGet(SSkipList *pSkipList, SSkipListKey pKey, int16_t keyType) {
+  int32_t sLevel = pSkipList->level - 1;
   int32_t ret = -1;
 
-  tSkipListNode *x = &pSkipList->pHead;
+  // result list
+  SArray* sa = taosArrayInit(1, POINTER_BYTES);
+  
+  SSkipListNode *pNode = pSkipList->pHead;
+ 
+  if (pSkipList->lock) {
+    pthread_rwlock_rdlock(pSkipList->lock);
+  }
 
-  pthread_rwlock_rdlock(&pSkipList->lock);
+#if SKIP_LIST_RECORD_PERFORMANCE
   pSkipList->state.queryCount++;
+#endif
 
-  __compar_fn_t filterComparator = getKeyFilterComparator(pSkipList, pKey->nType);
+  __compar_fn_t filterComparFn = getKeyFilterComparator(pSkipList, keyType);
 
   for (int32_t i = sLevel; i >= 0; --i) {
-    while (x->pForward[i] != NULL && (ret = filterComparator(&x->pForward[i]->key, pKey)) < 0) {
-      x = x->pForward[i];
-    }
-
-    if (ret == 0) {
-      pthread_rwlock_unlock(&pSkipList->lock);
-      return x->pForward[i];
-    }
-  }
-
-  pthread_rwlock_unlock(&pSkipList->lock);
-  return NULL;
-}
-
-static int32_t tSkipListEndParQuery(tSkipList *pSkipList, tSkipListNode *pStartNode, tSkipListKey *pEndKey,
-                                    int32_t cond, tSkipListNode ***pRes) {
-  pthread_rwlock_rdlock(&pSkipList->lock);
-  tSkipListNode *p = pStartNode;
-  int32_t        numOfRes = 0;
-
-  __compar_fn_t filterComparator = getKeyFilterComparator(pSkipList, pEndKey->nType);
-  while (p != NULL) {
-    int32_t ret = filterComparator(&p->key, pEndKey);
-    if (ret > 0) {
-      break;
-    }
-
-    if (ret < 0) {
-      numOfRes++;
-      p = p->pForward[0];
-    } else if (ret == 0) {
-      if (cond == TSDB_RELATION_LESS_EQUAL) {
-        numOfRes++;
-        p = p->pForward[0];
+    SSkipListNode *pNext = SL_GET_FORWARD_POINTER(pNode, i);
+    while (pNext != NULL) {
+      char *key = SL_GET_NODE_KEY(pSkipList, pNext);
+      if ((ret = filterComparFn(key, pKey)) < 0) {
+        pNode = pNext;
+        pNext = SL_GET_FORWARD_POINTER(pNext, i);
       } else {
         break;
       }
     }
-  }
-
-  (*pRes) = (tSkipListNode **)malloc(POINTER_BYTES * numOfRes);
-  for (int32_t i = 0; i < numOfRes; ++i) {
-    (*pRes)[i] = pStartNode;
-    pStartNode = pStartNode->pForward[0];
-  }
-  pthread_rwlock_unlock(&pSkipList->lock);
-
-  return numOfRes;
-}
-
-/*
- * maybe return the copy of tSkipListNode would be better
- */
-int32_t tSkipListGets(tSkipList *pSkipList, tSkipListKey *pKey, tSkipListNode ***pRes) {
-  (*pRes) = NULL;
 
-  tSkipListNode *pNode = tSkipListGetOne(pSkipList, pKey);
-  if (pNode == NULL) {
-    return 0;
-  }
-
-  __compar_fn_t filterComparator = getKeyFilterComparator(pSkipList, pKey->nType);
-
-  // backward check if previous nodes are with the same value.
-  tSkipListNode *pPrev = pNode->pBackward[0];
-  while ((pPrev != &pSkipList->pHead) && filterComparator(&pPrev->key, pKey) == 0) {
-    pPrev = pPrev->pBackward[0];
-  }
-
-  return tSkipListEndParQuery(pSkipList, pPrev->pForward[0], &pNode->key, TSDB_RELATION_LESS_EQUAL, pRes);
-}
-
-static tSkipListNode *tSkipListParQuery(tSkipList *pSkipList, tSkipListKey *pKey, int32_t cond) {
-  int32_t sLevel = pSkipList->nLevel - 1;
-  int32_t ret = -1;
-
-  tSkipListNode *x = &pSkipList->pHead;
-  __compar_fn_t  filterComparator = getKeyFilterComparator(pSkipList, pKey->nType);
-
-  pthread_rwlock_rdlock(&pSkipList->lock);
-
-  if (cond == TSDB_RELATION_LARGE_EQUAL || cond == TSDB_RELATION_LARGE) {
-    for (int32_t i = sLevel; i >= 0; --i) {
-      while (x->pForward[i] != NULL && (ret = filterComparator(&x->pForward[i]->key, pKey)) < 0) {
-        x = x->pForward[i];
-      }
-    }
-
-    // backward check if previous nodes are with the same value.
-    if (cond == TSDB_RELATION_LARGE_EQUAL && ret == 0) {
-      tSkipListNode *pNode = x->pForward[0];
-      while ((pNode->pBackward[0] != &pSkipList->pHead) && (filterComparator(&pNode->pBackward[0]->key, pKey) == 0)) {
-        pNode = pNode->pBackward[0];
+    // find the qualified key
+    if (ret == 0) {
+      if (pSkipList->lock) {
+        pthread_rwlock_unlock(pSkipList->lock);
       }
-      pthread_rwlock_unlock(&pSkipList->lock);
-      return pNode;
-    }
 
-    if (ret > 0 || cond == TSDB_RELATION_LARGE_EQUAL) {
-      pthread_rwlock_unlock(&pSkipList->lock);
-      return x->pForward[0];
-    } else {  // cond == TSDB_RELATION_LARGE && ret == 0
-      tSkipListNode *pn = x->pForward[0];
-      while (pn != NULL && filterComparator(&pn->key, pKey) == 0) {
-        pn = pn->pForward[0];
+      SSkipListNode* pResult = SL_GET_FORWARD_POINTER(pNode, i);
+      taosArrayPush(sa, &pResult);
+      
+      // skip list does not allowed duplicated key, abort further retrieve data
+      if (!pSkipList->keyInfo.dupKey) {
+        break;
       }
-      pthread_rwlock_unlock(&pSkipList->lock);
-      return pn;
-    }
-  }
-
-  pthread_rwlock_unlock(&pSkipList->lock);
-  return NULL;
-}
-
-int32_t tSkipListIterateList(tSkipList *pSkipList, tSkipListNode ***pRes, bool (*fp)(tSkipListNode *, void *),
-                             void *param) {
-  (*pRes) = (tSkipListNode **)calloc(1, POINTER_BYTES * pSkipList->nSize);
-  if (NULL == *pRes) {
-    pError("error skiplist %p, malloc failed", pSkipList);
-    return -1;
-  }
-  
-  pthread_rwlock_rdlock(&pSkipList->lock);
-  tSkipListNode *pStartNode = pSkipList->pHead.pForward[0];
-  int32_t        num = 0;
-
-  for (int32_t i = 0; i < pSkipList->nSize; ++i) {
-    if (pStartNode == NULL) {
-      pError("error skiplist %p, required length:%d, actual length:%d", pSkipList, pSkipList->nSize, i - 1);
-#ifdef _DEBUG_VIEW
-      tSkipListPrint(pSkipList, 1);
-#endif
-      break;
     }
-
-    if (fp == NULL || (fp != NULL && fp(pStartNode, param) == true)) {
-      (*pRes)[num++] = pStartNode;
-    }
-
-    pStartNode = pStartNode->pForward[0];
-  }
-
-  pthread_rwlock_unlock(&pSkipList->lock);
-
-  if (num == 0) {
-    free(*pRes);
-    *pRes = NULL;
-  } else if (num < pSkipList->nSize) { // free unused memory
-    char* tmp = realloc((*pRes), num * POINTER_BYTES);
-    assert(tmp != NULL);
-
-    *pRes = (tSkipListNode**)tmp;
   }
 
-  return num;
-}
-
-int32_t tSkipListIteratorReset(tSkipList *pSkipList, SSkipListIterator* iter) {
-  if (pSkipList == NULL) {
-    return -1;
-  }
-
-  iter->pSkipList = pSkipList;
-
-  pthread_rwlock_rdlock(&pSkipList->lock);
-  iter->cur = NULL;//pSkipList->pHead.pForward[0];
-  iter->num = pSkipList->nSize;
-  pthread_rwlock_unlock(&pSkipList->lock);
-
-  return 0;
-}
-
-bool tSkipListIteratorNext(SSkipListIterator* iter) {
-  if (iter->num == 0 || iter->pSkipList == NULL) {
-    return false;
-  }
-
-  tSkipList* pSkipList = iter->pSkipList;
-
-  pthread_rwlock_rdlock(&pSkipList->lock);
-  if (iter->cur == NULL) {
-    iter->cur = pSkipList->pHead.pForward[0];
-  } else {
-    iter->cur = iter->cur->pForward[0];
-  }
-
-  pthread_rwlock_unlock(&pSkipList->lock);
-
-  return iter->cur != NULL;
-}
-
-tSkipListNode* tSkipListIteratorGet(SSkipListIterator* iter) {
-  return iter->cur;
-}
-
-int32_t tSkipListRangeQuery(tSkipList *pSkipList, tSKipListQueryCond *pCond, tSkipListNode ***pRes) {
-  pSkipList->state.queryCount++;
-  tSkipListNode *pStart = tSkipListParQuery(pSkipList, &pCond->lowerBnd, pCond->lowerBndRelOptr);
-  if (pStart == 0) {
-    *pRes = NULL;
-    return 0;
-  }
-
-  return tSkipListEndParQuery(pSkipList, pStart, &pCond->upperBnd, pCond->upperBndRelOptr, pRes);
-}
-
-static bool removeSupport(tSkipList *pSkipList, tSkipListNode **forward, tSkipListKey *pKey) {
-  __compar_fn_t filterComparator = getKeyFilterComparator(pSkipList, pKey->nType);
-
-  if (filterComparator(&forward[0]->pForward[0]->key, pKey) == 0) {
-    tSkipListNode *p = forward[0]->pForward[0];
-    doRemove(pSkipList, p, forward);
-  } else {  // failed to find the node of specified value,abort
-    return false;
-  }
-
-  // compress the minimum level of skip list
-  while (pSkipList->nLevel > 0 && pSkipList->pHead.pForward[pSkipList->nLevel - 1] == NULL) {
-    pSkipList->nLevel -= 1;
-  }
-
-  return true;
-}
-
-void tSkipListRemoveNode(tSkipList *pSkipList, tSkipListNode *pNode) {
-  tSkipListNode *forward[MAX_SKIP_LIST_LEVEL] = {0};
-
-  pthread_rwlock_rdlock(&pSkipList->lock);
-  for (int32_t i = 0; i < pNode->nLevel; ++i) {
-    forward[i] = pNode->pBackward[i];
-  }
-
-  removeSupport(pSkipList, forward, &pNode->key);
-  pthread_rwlock_unlock(&pSkipList->lock);
-}
-
-bool tSkipListRemove(tSkipList *pSkipList, tSkipListKey *pKey) {
-  tSkipListNode *forward[MAX_SKIP_LIST_LEVEL] = {0};
-  __compar_fn_t  filterComparator = getKeyFilterComparator(pSkipList, pKey->nType);
-
-  pthread_rwlock_rdlock(&pSkipList->lock);
-
-  tSkipListNode *x = &pSkipList->pHead;
-  for (int32_t i = pSkipList->nLevel - 1; i >= 0; --i) {
-    while (x->pForward[i] != NULL && (filterComparator(&x->pForward[i]->key, pKey) < 0)) {
-      x = x->pForward[i];
-    }
-    forward[i] = x;
-  }
-
-  bool ret = removeSupport(pSkipList, forward, pKey);
-  pthread_rwlock_unlock(&pSkipList->lock);
-
-  return ret;
-}
-
-void tSkipListPrint(tSkipList *pSkipList, int16_t nlevel) {
-  if (pSkipList == NULL || pSkipList->nLevel < nlevel || nlevel <= 0) {
+  if (pSkipList->lock) {
+    pthread_rwlock_unlock(pSkipList->lock);
+  }
+
+  return sa;
+}
+
+// static int32_t tSkipListEndParQuery(SSkipList *pSkipList, SSkipListNode *pStartNode, SSkipListKey *pEndKey,
+//                                    int32_t cond, SSkipListNode ***pRes) {
+//  pthread_rwlock_rdlock(&pSkipList->lock);
+//  SSkipListNode *p = pStartNode;
+//  int32_t        numOfRes = 0;
+//
+//  __compar_fn_t filterComparFn = getKeyFilterComparator(pSkipList, pEndKey->nType);
+//  while (p != NULL) {
+//    int32_t ret = filterComparFn(&p->key, pEndKey);
+//    if (ret > 0) {
+//      break;
+//    }
+//
+//    if (ret < 0) {
+//      numOfRes++;
+//      p = p->pForward[0];
+//    } else if (ret == 0) {
+//      if (cond == TSDB_RELATION_LESS_EQUAL) {
+//        numOfRes++;
+//        p = p->pForward[0];
+//      } else {
+//        break;
+//      }
+//    }
+//  }
+//
+//  (*pRes) = (SSkipListNode **)malloc(POINTER_BYTES * numOfRes);
+//  for (int32_t i = 0; i < numOfRes; ++i) {
+//    (*pRes)[i] = pStartNode;
+//    pStartNode = pStartNode->pForward[0];
+//  }
+//  pthread_rwlock_unlock(&pSkipList->lock);
+//
+//  return numOfRes;
+//}
+//
+///*
+// * maybe return the copy of SSkipListNode would be better
+// */
+// int32_t tSkipListGets(SSkipList *pSkipList, SSkipListKey *pKey, SSkipListNode ***pRes) {
+//  (*pRes) = NULL;
+//
+//  SSkipListNode *pNode = tSkipListGet(pSkipList, pKey);
+//  if (pNode == NULL) {
+//    return 0;
+//  }
+//
+//  __compar_fn_t filterComparFn = getKeyFilterComparator(pSkipList, pKey->nType);
+//
+//  // backward check if previous nodes are with the same value.
+//  SSkipListNode *pPrev = pNode->pBackward[0];
+//  while ((pPrev != &pSkipList->pHead) && filterComparFn(&pPrev->key, pKey) == 0) {
+//    pPrev = pPrev->pBackward[0];
+//  }
+//
+//  return tSkipListEndParQuery(pSkipList, pPrev->pForward[0], &pNode->key, TSDB_RELATION_LESS_EQUAL, pRes);
+//}
+//
+// static SSkipListNode *tSkipListParQuery(SSkipList *pSkipList, SSkipListKey *pKey, int32_t cond) {
+//  int32_t sLevel = pSkipList->level - 1;
+//  int32_t ret = -1;
+//
+//  SSkipListNode *x = &pSkipList->pHead;
+//  __compar_fn_t  filterComparFn = getKeyFilterComparator(pSkipList, pKey->nType);
+//
+//  pthread_rwlock_rdlock(&pSkipList->lock);
+//
+//  if (cond == TSDB_RELATION_LARGE_EQUAL || cond == TSDB_RELATION_LARGE) {
+//    for (int32_t i = sLevel; i >= 0; --i) {
+//      while (x->pForward[i] != NULL && (ret = filterComparFn(&x->pForward[i]->key, pKey)) < 0) {
+//        x = x->pForward[i];
+//      }
+//    }
+//
+//    // backward check if previous nodes are with the same value.
+//    if (cond == TSDB_RELATION_LARGE_EQUAL && ret == 0) {
+//      SSkipListNode *pNode = x->pForward[0];
+//      while ((pNode->pBackward[0] != &pSkipList->pHead) && (filterComparFn(&pNode->pBackward[0]->key, pKey) == 0)) {
+//        pNode = pNode->pBackward[0];
+//      }
+//      pthread_rwlock_unlock(&pSkipList->lock);
+//      return pNode;
+//    }
+//
+//    if (ret > 0 || cond == TSDB_RELATION_LARGE_EQUAL) {
+//      pthread_rwlock_unlock(&pSkipList->lock);
+//      return x->pForward[0];
+//    } else {  // cond == TSDB_RELATION_LARGE && ret == 0
+//      SSkipListNode *pn = x->pForward[0];
+//      while (pn != NULL && filterComparFn(&pn->key, pKey) == 0) {
+//        pn = pn->pForward[0];
+//      }
+//      pthread_rwlock_unlock(&pSkipList->lock);
+//      return pn;
+//    }
+//  }
+//
+//  pthread_rwlock_unlock(&pSkipList->lock);
+//  return NULL;
+//}
+//
+// int32_t tSkipListIterateList(SSkipList *pSkipList, SSkipListNode ***pRes, bool (*fp)(SSkipListNode *, void *),
+//                             void *param) {
+//  (*pRes) = (SSkipListNode **)calloc(1, POINTER_BYTES * pSkipList->nSize);
+//  if (NULL == *pRes) {
+//    pError("error skiplist %p, malloc failed", pSkipList);
+//    return -1;
+//  }
+//
+//  pthread_rwlock_rdlock(&pSkipList->lock);
+//  SSkipListNode *pStartNode = pSkipList->pHead.pForward[0];
+//  int32_t        num = 0;
+//
+//  for (int32_t i = 0; i < pSkipList->nSize; ++i) {
+//    if (pStartNode == NULL) {
+//      pError("error skiplist %p, required length:%d, actual length:%d", pSkipList, pSkipList->nSize, i - 1);
+//#ifdef _DEBUG_VIEW
+//      tSkipListPrint(pSkipList, 1);
+//#endif
+//      break;
+//    }
+//
+//    if (fp == NULL || (fp != NULL && fp(pStartNode, param) == true)) {
+//      (*pRes)[num++] = pStartNode;
+//    }
+//
+//    pStartNode = pStartNode->pForward[0];
+//  }
+//
+//  pthread_rwlock_unlock(&pSkipList->lock);
+//
+//  if (num == 0) {
+//    free(*pRes);
+//    *pRes = NULL;
+//  } else if (num < pSkipList->nSize) {  // free unused memory
+//    char *tmp = realloc((*pRes), num * POINTER_BYTES);
+//    assert(tmp != NULL);
+//
+//    *pRes = (SSkipListNode **)tmp;
+//  }
+//
+//  return num;
+//}
+//
+// int32_t tSkipListIteratorReset(SSkipList *pSkipList, SSkipListIterator *iter) {
+//  if (pSkipList == NULL) {
+//    return -1;
+//  }
+//
+//  iter->pSkipList = pSkipList;
+//  if (pSkipList->lock) {
+//    pthread_rwlock_rdlock(&pSkipList->lock);
+//  }
+//  iter->cur = NULL;  // pSkipList->pHead.pForward[0];
+//  iter->num = pSkipList->size;
+//
+//  if (pSkipList->lock) {
+//    pthread_rwlock_unlock(&pSkipList->lock);
+//  }
+//
+//  return 0;
+//}
+//
+// bool tSkipListIteratorNext(SSkipListIterator *iter) {
+//  if (iter->num == 0 || iter->pSkipList == NULL) {
+//    return false;
+//  }
+//
+//  SSkipList *pSkipList = iter->pSkipList;
+//
+//  pthread_rwlock_rdlock(&pSkipList->lock);
+//  if (iter->cur == NULL) {
+//    iter->cur = pSkipList->pHead.pForward[0];
+//  } else {
+//    iter->cur = iter->cur->pForward[0];
+//  }
+//
+//  pthread_rwlock_unlock(&pSkipList->lock);
+//
+//  return iter->cur != NULL;
+//}
+//
+// SSkipListNode *tSkipListIteratorGet(SSkipListIterator *iter) { return iter->cur; }
+//
+// int32_t tSkipListRangeQuery(SSkipList *pSkipList, tSKipListQueryCond *pCond, SSkipListNode ***pRes) {
+//  pSkipList->state.queryCount++;
+//  SSkipListNode *pStart = tSkipListParQuery(pSkipList, &pCond->lowerBnd, pCond->lowerBndRelOptr);
+//  if (pStart == 0) {
+//    *pRes = NULL;
+//    return 0;
+//  }
+//
+//  return tSkipListEndParQuery(pSkipList, pStart, &pCond->upperBnd, pCond->upperBndRelOptr, pRes);
+//}
+//
+// static bool removeSupport(SSkipList *pSkipList, SSkipListNode **forward, SSkipListKey *pKey) {
+//  __compar_fn_t filterComparFn = getKeyFilterComparator(pSkipList, pKey->nType);
+//
+//  if (filterComparFn(&forward[0]->pForward[0]->key, pKey) == 0) {
+//    SSkipListNode *p = forward[0]->pForward[0];
+//    doRemove(pSkipList, p, forward);
+//  } else {  // failed to find the node of specified value,abort
+//    return false;
+//  }
+//
+//  // compress the minimum level of skip list
+//  while (pSkipList->level > 0 && pSkipList->pHead.pForward[pSkipList->level - 1] == NULL) {
+//    pSkipList->level -= 1;
+//  }
+//
+//  return true;
+//}
+//
+// void tSkipListRemoveNode(SSkipList *pSkipList, SSkipListNode *pNode) {
+//  SSkipListNode *forward[MAX_SKIP_LIST_LEVEL] = {0};
+//
+//  pthread_rwlock_rdlock(&pSkipList->lock);
+//  for (int32_t i = 0; i < pNode->level; ++i) {
+//    forward[i] = pNode->pBackward[i];
+//  }
+//
+//  removeSupport(pSkipList, forward, &pNode->key);
+//  pthread_rwlock_unlock(&pSkipList->lock);
+//}
+//
+// bool tSkipListRemove(SSkipList *pSkipList, SSkipListKey *pKey) {
+//  SSkipListNode *forward[MAX_SKIP_LIST_LEVEL] = {0};
+//  __compar_fn_t  filterComparFn = getKeyFilterComparator(pSkipList, pKey->nType);
+//
+//  pthread_rwlock_rdlock(&pSkipList->lock);
+//
+//  SSkipListNode *x = &pSkipList->pHead;
+//  for (int32_t i = pSkipList->level - 1; i >= 0; --i) {
+//    while (x->pForward[i] != NULL && (filterComparFn(&x->pForward[i]->key, pKey) < 0)) {
+//      x = x->pForward[i];
+//    }
+//    forward[i] = x;
+//  }
+//
+//  bool ret = removeSupport(pSkipList, forward, pKey);
+//  pthread_rwlock_unlock(&pSkipList->lock);
+//
+//  return ret;
+//}
+
+void tSkipListPrint(SSkipList *pSkipList, int16_t nlevel) {
+  if (pSkipList == NULL || pSkipList->level < nlevel || nlevel <= 0) {
     return;
   }
 
-  tSkipListNode *p = pSkipList->pHead.pForward[nlevel - 1];
+  SSkipListNode *p = SL_GET_FORWARD_POINTER(pSkipList->pHead, nlevel - 1);
   int32_t        id = 1;
+
   while (p) {
-    switch (pSkipList->keyType) {
+    char *key = SL_GET_NODE_KEY(pSkipList, p);
+    switch (pSkipList->keyInfo.type) {
       case TSDB_DATA_TYPE_INT:
       case TSDB_DATA_TYPE_SMALLINT:
       case TSDB_DATA_TYPE_TINYINT:
       case TSDB_DATA_TYPE_BIGINT:
-        fprintf(stdout, "%d: %" PRId64 " \n", id++, p->key.i64Key);
+        fprintf(stdout, "%d: %" PRId64 " \n", id++, *(int64_t *)key);
         break;
       case TSDB_DATA_TYPE_BINARY:
-        fprintf(stdout, "%d: %s \n", id++, p->key.pz);
+        fprintf(stdout, "%d: %s \n", id++, key);
         break;
       case TSDB_DATA_TYPE_DOUBLE:
-        fprintf(stdout, "%d: %lf \n", id++, p->key.dKey);
+        fprintf(stdout, "%d: %lf \n", id++, *(double *)key);
         break;
       default:
         fprintf(stdout, "\n");
     }
-    p = p->pForward[nlevel - 1];
-  }
-}
-
-/*
- * query processor based on query condition
- */
-int32_t tSkipListQuery(tSkipList *pSkipList, tSKipListQueryCond *pQueryCond, tSkipListNode ***pResult) {
-  // query condition check
-  int32_t       rel = 0;
-  __compar_fn_t comparator = getKeyComparator(pQueryCond->lowerBnd.nType);
-
-  if (pSkipList == NULL || pQueryCond == NULL || pSkipList->nSize == 0 ||
-      (((rel = comparator(&pQueryCond->lowerBnd, &pQueryCond->upperBnd)) > 0 &&
-        pQueryCond->lowerBnd.nType != TSDB_DATA_TYPE_NCHAR && pQueryCond->lowerBnd.nType != TSDB_DATA_TYPE_BINARY))) {
-    (*pResult) = NULL;
-    return 0;
-  }
-
-  if (rel == 0) {
-    /*
-     * 0 means: pQueryCond->lowerBnd == pQueryCond->upperBnd
-     * point query
-     */
-    if (pQueryCond->lowerBndRelOptr == TSDB_RELATION_LARGE_EQUAL &&
-        pQueryCond->upperBndRelOptr == TSDB_RELATION_LESS_EQUAL) {  // point query
-      return tSkipListGets(pSkipList, &pQueryCond->lowerBnd, pResult);
-    } else {
-      (*pResult) = NULL;
-      return 0;
-    }
-  } else {
-    /* range query, query operation code check */
-    return tSkipListRangeQuery(pSkipList, pQueryCond, pResult);
-  }
-}
-
-typedef struct MultipleQueryResult {
-  int32_t         len;
-  tSkipListNode **pData;
-} MultipleQueryResult;
-
-static int32_t mergeQueryResult(MultipleQueryResult *pResults, int32_t numOfResSet, tSkipListNode ***pRes) {
-  int32_t total = 0;
-  for (int32_t i = 0; i < numOfResSet; ++i) {
-    total += pResults[i].len;
-  }
-
-  (*pRes) = malloc(POINTER_BYTES * total);
-  int32_t idx = 0;
-
-  for (int32_t i = 0; i < numOfResSet; ++i) {
-    MultipleQueryResult *pOneResult = &pResults[i];
-    for (int32_t j = 0; j < pOneResult->len; ++j) {
-      (*pRes)[idx++] = pOneResult->pData[j];
-    }
-  }
-
-  return total;
-}
-
-static void removeDuplicateKey(tSkipListKey *pKey, int32_t *numOfKey, __compar_fn_t comparator) {
-  if (*numOfKey == 1) {
-    return;
-  }
-
-  qsort(pKey, *numOfKey, sizeof(pKey[0]), comparator);
-  int32_t i = 0, j = 1;
-
-  while (i < (*numOfKey) && j < (*numOfKey)) {
-    int32_t ret = comparator(&pKey[i], &pKey[j]);
-    if (ret == 0) {
-      j++;
-    } else {
-      pKey[i + 1] = pKey[j];
-      i++;
-      j++;
-    }
-  }
-
-  (*numOfKey) = i + 1;
-}
-
-int32_t mergeResult(const tSkipListKey *pKey, int32_t numOfKey, tSkipListNode ***pRes, __compar_fn_t comparator,
-                    tSkipListNode *pNode) {
-  int32_t i = 0, j = 0;
-  // merge two sorted arrays in O(n) time
-  while (i < numOfKey && pNode != NULL) {
-    int32_t ret = comparator(&pNode->key, &pKey[i]);
-    if (ret < 0) {
-      (*pRes)[j++] = pNode;
-      pNode = pNode->pForward[0];
-    } else if (ret == 0) {
-      pNode = pNode->pForward[0];
-    } else {  // pNode->key > pkey[i]
-      i++;
-    }
-  }
 
-  while (pNode != NULL) {
-    (*pRes)[j++] = pNode;
-    pNode = pNode->pForward[0];
-  }
-  return j;
-}
-
-int32_t tSkipListPointQuery(tSkipList *pSkipList, tSkipListKey *pKey, int32_t numOfKey, tSkipListPointQueryType type,
-                            tSkipListNode ***pRes) {
-  if (numOfKey == 0 || pKey == NULL || pSkipList == NULL || pSkipList->nSize == 0 ||
-      (type != INCLUDE_POINT_QUERY && type != EXCLUDE_POINT_QUERY)) {
-    (*pRes) = NULL;
-    return 0;
-  }
-
-  __compar_fn_t comparator = getKeyComparator(pKey->nType);
-  removeDuplicateKey(pKey, &numOfKey, comparator);
-
-  if (type == INCLUDE_POINT_QUERY) {
-    if (numOfKey == 1) {
-      return tSkipListGets(pSkipList, &pKey[0], pRes);
-    } else {
-      MultipleQueryResult *pTempResult = (MultipleQueryResult *)malloc(sizeof(MultipleQueryResult) * numOfKey);
-      for (int32_t i = 0; i < numOfKey; ++i) {
-        pTempResult[i].len = tSkipListGets(pSkipList, &pKey[i], &pTempResult[i].pData);
-      }
-      int32_t num = mergeQueryResult(pTempResult, numOfKey, pRes);
-
-      for (int32_t i = 0; i < numOfKey; ++i) {
-        free(pTempResult[i].pData);
-      }
-      free(pTempResult);
-      return num;
-    }
-  } else {  // exclude query
-    *pRes = malloc(POINTER_BYTES * pSkipList->nSize);
-
-    __compar_fn_t filterComparator = getKeyFilterComparator(pSkipList, pKey->nType);
-
-    tSkipListNode *pNode = pSkipList->pHead.pForward[0];
-    int32_t        retLen = mergeResult(pKey, numOfKey, pRes, filterComparator, pNode);
-
-    if (retLen < pSkipList->nSize) {
-      (*pRes) = realloc(*pRes, POINTER_BYTES * retLen);
-    }
-    return retLen;
+    p = SL_GET_FORWARD_POINTER(p, nlevel - 1);
+    //    p = p->pForward[nlevel - 1];
   }
 }