From 3ef067ff0354fba22bf9c99b424266584469b2cd Mon Sep 17 00:00:00 2001 From: Ganlin Zhao Date: Mon, 16 May 2022 11:03:15 +0800 Subject: [PATCH 1/5] feat(query): add tail function --- source/libs/function/inc/builtinsimpl.h | 7 +- source/libs/function/src/builtins.c | 36 +++++++++ source/libs/function/src/builtinsimpl.c | 100 ++++++++++++++++++++++++ 3 files changed, 142 insertions(+), 1 deletion(-) diff --git a/source/libs/function/inc/builtinsimpl.h b/source/libs/function/inc/builtinsimpl.h index 807234a1b1..c25d74911c 100644 --- a/source/libs/function/inc/builtinsimpl.h +++ b/source/libs/function/inc/builtinsimpl.h @@ -105,7 +105,12 @@ int32_t mavgFunction(SqlFunctionCtx* pCtx); bool getSampleFuncEnv(struct SFunctionNode* pFunc, SFuncExecEnv* pEnv); bool sampleFunctionSetup(SqlFunctionCtx *pCtx, SResultRowEntryInfo* pResultInfo); int32_t sampleFunction(SqlFunctionCtx* pCtx); -int32_t sampleFinalize(SqlFunctionCtx* pCtx, SSDataBlock* pBlock); +//int32_t sampleFinalize(SqlFunctionCtx* pCtx, SSDataBlock* pBlock); + +bool getTailFuncEnv(struct SFunctionNode* pFunc, SFuncExecEnv* pEnv); +bool tailFunctionSetup(SqlFunctionCtx *pCtx, SResultRowEntryInfo* pResultInfo); +int32_t tailFunction(SqlFunctionCtx* pCtx); +int32_t tailFinalize(SqlFunctionCtx* pCtx, SSDataBlock* pBlock); bool getSelectivityFuncEnv(SFunctionNode* pFunc, SFuncExecEnv* pEnv); diff --git a/source/libs/function/src/builtins.c b/source/libs/function/src/builtins.c index fc93008312..282b527b31 100644 --- a/source/libs/function/src/builtins.c +++ b/source/libs/function/src/builtins.c @@ -386,6 +386,32 @@ static int32_t translateSample(SFunctionNode* pFunc, char* pErrBuf, int32_t len) return TSDB_CODE_SUCCESS; } +static int32_t translateTail(SFunctionNode* pFunc, char* pErrBuf, int32_t len) { + if (2 != LIST_LENGTH(pFunc->pParameterList)) { + return invaildFuncParaNumErrMsg(pErrBuf, len, pFunc->functionName); + } + + SNode* pPara = nodesListGetNode(pFunc->pParameterList, 0); + if (QUERY_NODE_COLUMN != nodeType(pPara)) { + return buildFuncErrMsg(pErrBuf, len, TSDB_CODE_FUNC_FUNTION_ERROR, + "The input parameter of TAIL function can only be column"); + } + + uint8_t paraType = ((SExprNode*)nodesListGetNode(pFunc->pParameterList, 1))->resType.type; + if (!IS_INTEGER_TYPE(paraType)) { + return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName); + } + + SExprNode* pCol = (SExprNode*)nodesListGetNode(pFunc->pParameterList, 0); + uint8_t colType = pCol->resType.type; + if (IS_VAR_DATA_TYPE(colType)) { + pFunc->node.resType = (SDataType){.bytes = pCol->resType.bytes, .type = colType}; + } else { + pFunc->node.resType = (SDataType){.bytes = tDataTypes[colType].bytes, .type = colType}; + } + return TSDB_CODE_SUCCESS; +} + static int32_t translateLastRow(SFunctionNode* pFunc, char* pErrBuf, int32_t len) { // todo return TSDB_CODE_SUCCESS; @@ -850,6 +876,16 @@ const SBuiltinFuncDefinition funcMgtBuiltins[] = { .processFunc = sampleFunction, .finalizeFunc = NULL }, + { + .name = "tail", + .type = FUNCTION_TYPE_TAIL, + .classification = FUNC_MGT_NONSTANDARD_SQL_FUNC | FUNC_MGT_TIMELINE_FUNC, + .translateFunc = translateTail, + .getEnvFunc = getTailFuncEnv, + .initFunc = tailFunctionSetup, + .processFunc = tailFunction, + .finalizeFunc = NULL + }, { .name = "abs", .type = FUNCTION_TYPE_ABS, diff --git a/source/libs/function/src/builtinsimpl.c b/source/libs/function/src/builtinsimpl.c index af86eb4e90..02382cc228 100644 --- a/source/libs/function/src/builtinsimpl.c +++ b/source/libs/function/src/builtinsimpl.c @@ -18,12 +18,15 @@ #include "function.h" #include "querynodes.h" #include "taggfunction.h" +#include "tcompare.h" #include "tdatablock.h" #include "tpercentile.h" #define HISTOGRAM_MAX_BINS_NUM 1000 #define MAVG_MAX_POINTS_NUM 1000 #define SAMPLE_MAX_POINTS_NUM 1000 +#define TAIL_MAX_POINTS_NUM 100 +#define TAIL_MAX_OFFSET 100 typedef struct SSumRes { union { @@ -161,6 +164,20 @@ typedef struct SSampleInfo { int64_t *timestamp; } SSampleInfo; +typedef struct STailUnit { + int64_t timestamp; + char data[]; +} STailUnit; + +typedef struct STailInfo { + int32_t numOfPoints; + int32_t numAdded; + int32_t offset; + uint8_t colType; + int16_t colBytes; + STailUnit **pRes; +} STailInfo; + #define SET_VAL(_info, numOfElem, res) \ do { \ if ((numOfElem) <= 0) { \ @@ -3141,3 +3158,86 @@ int32_t sampleFunction(SqlFunctionCtx* pCtx) { // // return pResInfo->numOfRes; //} + + +bool getTailFuncEnv(SFunctionNode* pFunc, SFuncExecEnv* pEnv) { + SColumnNode* pCol = (SColumnNode*)nodesListGetNode(pFunc->pParameterList, 0); + SValueNode* pVal = (SValueNode*)nodesListGetNode(pFunc->pParameterList, 1); + int32_t numOfPoints = pVal->datum.i; + pEnv->calcMemSize = sizeof(STailInfo) + numOfPoints * (POINTER_BYTES + sizeof(STailUnit) + pCol->node.resType.bytes); + return true; +} + +bool tailFunctionSetup(SqlFunctionCtx *pCtx, SResultRowEntryInfo *pResultInfo) { + if (!functionSetup(pCtx, pResultInfo)) { + return false; + } + + STailInfo *pInfo = GET_ROWCELL_INTERBUF(pResultInfo); + pInfo->numAdded = 0; + pInfo->numOfPoints = pCtx->param[1].param.i; + pInfo->offset = pCtx->param[2].param.i; + pInfo->colType = pCtx->resDataInfo.type; + pInfo->colBytes = pCtx->resDataInfo.bytes; + if ((pInfo->numOfPoints < 1 || pInfo->numOfPoints > TAIL_MAX_POINTS_NUM) || + (pInfo->numOfPoints < 0 || pInfo->numOfPoints > TAIL_MAX_OFFSET)) { + return false; + } + + pInfo->pRes = (STailUnit **)((char *)pInfo + sizeof(STailInfo)); + char *pUnit = (char *)pInfo->pRes + pInfo->numOfPoints * POINTER_BYTES; + + size_t unitSize = sizeof(STailUnit) + pInfo->colBytes; + for (int32_t i = 0; i < pInfo->numOfPoints; ++i) { + pInfo->pRes[i] = (STailUnit *)(pUnit + i * unitSize); + } + + return true; +} + +static void tailAssignResult(STailUnit* pUnit, char *data, int32_t colBytes, TSKEY ts) { + pUnit->timestamp = ts; + memcpy(pUnit->data, data, colBytes); +} + +static int32_t tailCompFn(const void *p1, const void *p2, const void *param) { + STailUnit *d1 = *(STailUnit **)p1; + STailUnit *d2 = *(STailUnit **)p2; + return compareInt64Val(&d1->timestamp, &d2->timestamp); +} + +static void doTailAdd(STailInfo* pInfo, char *data, TSKEY ts) { + STailUnit **pList = pInfo->pRes; + if (pInfo->numAdded < pInfo->numOfPoints) { + tailAssignResult(pList[pInfo->numAdded], data, pInfo->colBytes, ts); + taosheapsort((void *)pList, sizeof(STailUnit **), pInfo->numAdded + 1, NULL, tailCompFn, 0); + } else if (pList[0]->timestamp < ts) { + tailAssignResult(pList[0], data, pInfo->colBytes, ts); + taosheapadjust((void *)pList, sizeof(STailUnit **), 0, pInfo->numOfPoints - 1, NULL, tailCompFn, NULL, 0); + } +} + +int32_t tailFunction(SqlFunctionCtx* pCtx) { + SResultRowEntryInfo* pResInfo = GET_RES_INFO(pCtx); + STailInfo* pInfo = GET_ROWCELL_INTERBUF(pResInfo); + + SInputColumnInfoData* pInput = &pCtx->input; + TSKEY* tsList = (int64_t*)pInput->pPTS->pData; + + SColumnInfoData* pInputCol = pInput->pData[0]; + SColumnInfoData* pTsOutput = pCtx->pTsOutput; + SColumnInfoData* pOutput = (SColumnInfoData*)pCtx->pOutput; + + int32_t startOffset = pCtx->offset; + for (int32_t i = pInput->startRowIndex; i < pInput->numOfRows + pInput->startRowIndex; i += 1) { + if (colDataIsNull_f(pInputCol->nullbitmap, i)) { + //colDataAppendNULL(pOutput, i); + continue; + } + + char* data = colDataGetData(pInputCol, i); + doTailAdd(pInfo, data, tsList[i]); + } + + return pInfo->numOfPoints; +} From 4be158b391d29c9653f16032b03ec7f92611309d Mon Sep 17 00:00:00 2001 From: Ganlin Zhao Date: Mon, 16 May 2022 11:03:15 +0800 Subject: [PATCH 2/5] feat(query): add tail function --- source/libs/function/src/builtins.c | 2 +- source/libs/function/src/builtinsimpl.c | 64 ++++++++++++++++++------- 2 files changed, 48 insertions(+), 18 deletions(-) diff --git a/source/libs/function/src/builtins.c b/source/libs/function/src/builtins.c index 282b527b31..51f30aca21 100644 --- a/source/libs/function/src/builtins.c +++ b/source/libs/function/src/builtins.c @@ -884,7 +884,7 @@ const SBuiltinFuncDefinition funcMgtBuiltins[] = { .getEnvFunc = getTailFuncEnv, .initFunc = tailFunctionSetup, .processFunc = tailFunction, - .finalizeFunc = NULL + .finalizeFunc = tailFinalize }, { .name = "abs", diff --git a/source/libs/function/src/builtinsimpl.c b/source/libs/function/src/builtinsimpl.c index 02382cc228..7081a65dd0 100644 --- a/source/libs/function/src/builtinsimpl.c +++ b/source/libs/function/src/builtinsimpl.c @@ -164,10 +164,10 @@ typedef struct SSampleInfo { int64_t *timestamp; } SSampleInfo; -typedef struct STailUnit { +typedef struct STailItem { int64_t timestamp; char data[]; -} STailUnit; +} STailItem; typedef struct STailInfo { int32_t numOfPoints; @@ -175,7 +175,7 @@ typedef struct STailInfo { int32_t offset; uint8_t colType; int16_t colBytes; - STailUnit **pRes; + STailItem **pItems; } STailInfo; #define SET_VAL(_info, numOfElem, res) \ @@ -3164,7 +3164,7 @@ bool getTailFuncEnv(SFunctionNode* pFunc, SFuncExecEnv* pEnv) { SColumnNode* pCol = (SColumnNode*)nodesListGetNode(pFunc->pParameterList, 0); SValueNode* pVal = (SValueNode*)nodesListGetNode(pFunc->pParameterList, 1); int32_t numOfPoints = pVal->datum.i; - pEnv->calcMemSize = sizeof(STailInfo) + numOfPoints * (POINTER_BYTES + sizeof(STailUnit) + pCol->node.resType.bytes); + pEnv->calcMemSize = sizeof(STailInfo) + numOfPoints * (POINTER_BYTES + sizeof(STailItem) + pCol->node.resType.bytes); return true; } @@ -3184,36 +3184,37 @@ bool tailFunctionSetup(SqlFunctionCtx *pCtx, SResultRowEntryInfo *pResultInfo) { return false; } - pInfo->pRes = (STailUnit **)((char *)pInfo + sizeof(STailInfo)); - char *pUnit = (char *)pInfo->pRes + pInfo->numOfPoints * POINTER_BYTES; + pInfo->pItems = (STailItem **)((char *)pInfo + sizeof(STailInfo)); + char *pItem = (char *)pInfo->pItems + pInfo->numOfPoints * POINTER_BYTES; - size_t unitSize = sizeof(STailUnit) + pInfo->colBytes; + size_t unitSize = sizeof(STailItem) + pInfo->colBytes; for (int32_t i = 0; i < pInfo->numOfPoints; ++i) { - pInfo->pRes[i] = (STailUnit *)(pUnit + i * unitSize); + pInfo->pItems[i] = (STailItem *)(pItem + i * unitSize); } return true; } -static void tailAssignResult(STailUnit* pUnit, char *data, int32_t colBytes, TSKEY ts) { - pUnit->timestamp = ts; - memcpy(pUnit->data, data, colBytes); +static void tailAssignResult(STailItem* pItem, char *data, int32_t colBytes, TSKEY ts) { + pItem->timestamp = ts; + memcpy(pItem->data, data, colBytes); } static int32_t tailCompFn(const void *p1, const void *p2, const void *param) { - STailUnit *d1 = *(STailUnit **)p1; - STailUnit *d2 = *(STailUnit **)p2; + STailItem *d1 = *(STailItem **)p1; + STailItem *d2 = *(STailItem **)p2; return compareInt64Val(&d1->timestamp, &d2->timestamp); } static void doTailAdd(STailInfo* pInfo, char *data, TSKEY ts) { - STailUnit **pList = pInfo->pRes; + STailItem **pList = pInfo->pItems; if (pInfo->numAdded < pInfo->numOfPoints) { tailAssignResult(pList[pInfo->numAdded], data, pInfo->colBytes, ts); - taosheapsort((void *)pList, sizeof(STailUnit **), pInfo->numAdded + 1, NULL, tailCompFn, 0); + taosheapsort((void *)pList, sizeof(STailItem **), pInfo->numAdded + 1, NULL, tailCompFn, 0); + pInfo->numAdded++; } else if (pList[0]->timestamp < ts) { tailAssignResult(pList[0], data, pInfo->colBytes, ts); - taosheapadjust((void *)pList, sizeof(STailUnit **), 0, pInfo->numOfPoints - 1, NULL, tailCompFn, NULL, 0); + taosheapadjust((void *)pList, sizeof(STailItem **), 0, pInfo->numOfPoints - 1, NULL, tailCompFn, NULL, 0); } } @@ -3231,7 +3232,7 @@ int32_t tailFunction(SqlFunctionCtx* pCtx) { int32_t startOffset = pCtx->offset; for (int32_t i = pInput->startRowIndex; i < pInput->numOfRows + pInput->startRowIndex; i += 1) { if (colDataIsNull_f(pInputCol->nullbitmap, i)) { - //colDataAppendNULL(pOutput, i); + colDataAppendNULL(pOutput, i); continue; } @@ -3239,5 +3240,34 @@ int32_t tailFunction(SqlFunctionCtx* pCtx) { doTailAdd(pInfo, data, tsList[i]); } + for (int32_t i = 0; i < pInfo->numOfPoints; ++i) { + int32_t pos = startOffset + i; + STailItem *pItem = pInfo->pItems[i]; + colDataAppend(pOutput, pos, pItem->data, false); + } + return pInfo->numOfPoints; } + +int32_t tailFinalize(SqlFunctionCtx* pCtx, SSDataBlock* pBlock) { + SResultRowEntryInfo* pEntryInfo = GET_RES_INFO(pCtx); + STailInfo* pInfo = GET_ROWCELL_INTERBUF(pEntryInfo); + pEntryInfo->complete = true; + + int32_t type = pCtx->input.pData[0]->info.type; + int32_t slotId = pCtx->pExpr->base.resSchema.slotId; + + SColumnInfoData* pCol = taosArrayGet(pBlock->pDataBlock, slotId); + + // todo assign the tag value and the corresponding row data + int32_t currentRow = pBlock->info.rows; + for (int32_t i = 0; i < pEntryInfo->numOfRes; ++i) { + STailItem *pItem = pInfo->pItems[i]; + colDataAppend(pCol, currentRow, pItem->data, false); + + //setSelectivityValue(pCtx, pBlock, &pInfo->pItems[i].tuplePos, currentRow); + currentRow += 1; + } + + return pEntryInfo->numOfRes; +} From 21b5f72340c348cbda76bf069a86541236aeac28 Mon Sep 17 00:00:00 2001 From: Ganlin Zhao Date: Mon, 16 May 2022 16:35:59 +0800 Subject: [PATCH 3/5] fix(query): fix tail function NULL value handing. --- source/libs/function/src/builtinsimpl.c | 32 +++++++++++++++---------- 1 file changed, 20 insertions(+), 12 deletions(-) diff --git a/source/libs/function/src/builtinsimpl.c b/source/libs/function/src/builtinsimpl.c index 7081a65dd0..77cde174ee 100644 --- a/source/libs/function/src/builtinsimpl.c +++ b/source/libs/function/src/builtinsimpl.c @@ -166,6 +166,7 @@ typedef struct SSampleInfo { typedef struct STailItem { int64_t timestamp; + bool isNull; char data[]; } STailItem; @@ -3124,7 +3125,7 @@ int32_t sampleFunction(SqlFunctionCtx* pCtx) { int32_t startOffset = pCtx->offset; for (int32_t i = pInput->startRowIndex; i < pInput->numOfRows + pInput->startRowIndex; i += 1) { - if (colDataIsNull_f(pInputCol->nullbitmap, i)) { + if (colDataIsNull_s(pInputCol, i)) { //colDataAppendNULL(pOutput, i); continue; } @@ -3190,14 +3191,19 @@ bool tailFunctionSetup(SqlFunctionCtx *pCtx, SResultRowEntryInfo *pResultInfo) { size_t unitSize = sizeof(STailItem) + pInfo->colBytes; for (int32_t i = 0; i < pInfo->numOfPoints; ++i) { pInfo->pItems[i] = (STailItem *)(pItem + i * unitSize); + pInfo->pItems[i]->isNull = false; } return true; } -static void tailAssignResult(STailItem* pItem, char *data, int32_t colBytes, TSKEY ts) { +static void tailAssignResult(STailItem* pItem, char *data, int32_t colBytes, TSKEY ts, bool isNull) { pItem->timestamp = ts; - memcpy(pItem->data, data, colBytes); + if (isNull) { + pItem->isNull = true; + } else { + memcpy(pItem->data, data, colBytes); + } } static int32_t tailCompFn(const void *p1, const void *p2, const void *param) { @@ -3206,14 +3212,14 @@ static int32_t tailCompFn(const void *p1, const void *p2, const void *param) { return compareInt64Val(&d1->timestamp, &d2->timestamp); } -static void doTailAdd(STailInfo* pInfo, char *data, TSKEY ts) { +static void doTailAdd(STailInfo* pInfo, char *data, TSKEY ts, bool isNull) { STailItem **pList = pInfo->pItems; if (pInfo->numAdded < pInfo->numOfPoints) { - tailAssignResult(pList[pInfo->numAdded], data, pInfo->colBytes, ts); + tailAssignResult(pList[pInfo->numAdded], data, pInfo->colBytes, ts, isNull); taosheapsort((void *)pList, sizeof(STailItem **), pInfo->numAdded + 1, NULL, tailCompFn, 0); pInfo->numAdded++; } else if (pList[0]->timestamp < ts) { - tailAssignResult(pList[0], data, pInfo->colBytes, ts); + tailAssignResult(pList[0], data, pInfo->colBytes, ts, isNull); taosheapadjust((void *)pList, sizeof(STailItem **), 0, pInfo->numOfPoints - 1, NULL, tailCompFn, NULL, 0); } } @@ -3231,19 +3237,21 @@ int32_t tailFunction(SqlFunctionCtx* pCtx) { int32_t startOffset = pCtx->offset; for (int32_t i = pInput->startRowIndex; i < pInput->numOfRows + pInput->startRowIndex; i += 1) { - if (colDataIsNull_f(pInputCol->nullbitmap, i)) { - colDataAppendNULL(pOutput, i); - continue; - } char* data = colDataGetData(pInputCol, i); - doTailAdd(pInfo, data, tsList[i]); + doTailAdd(pInfo, data, tsList[i], colDataIsNull_s(pInputCol, i)); } + taosqsort(pInfo->pItems, pInfo->numOfPoints, POINTER_BYTES, NULL, tailCompFn); + for (int32_t i = 0; i < pInfo->numOfPoints; ++i) { int32_t pos = startOffset + i; STailItem *pItem = pInfo->pItems[i]; - colDataAppend(pOutput, pos, pItem->data, false); + if (pItem->isNull) { + colDataAppendNULL(pOutput, pos); + } else { + colDataAppend(pOutput, pos, pItem->data, false); + } } return pInfo->numOfPoints; From a281da1379eb2f8ca802064f96801add1cba5a07 Mon Sep 17 00:00:00 2001 From: Ganlin Zhao Date: Mon, 16 May 2022 17:02:01 +0800 Subject: [PATCH 4/5] fix(query): fix tail function points larger than total rows issue --- source/libs/function/src/builtinsimpl.c | 1 + 1 file changed, 1 insertion(+) diff --git a/source/libs/function/src/builtinsimpl.c b/source/libs/function/src/builtinsimpl.c index 77cde174ee..add33adb08 100644 --- a/source/libs/function/src/builtinsimpl.c +++ b/source/libs/function/src/builtinsimpl.c @@ -3236,6 +3236,7 @@ int32_t tailFunction(SqlFunctionCtx* pCtx) { SColumnInfoData* pOutput = (SColumnInfoData*)pCtx->pOutput; int32_t startOffset = pCtx->offset; + pInfo->numOfPoints = MIN(pInfo->numOfPoints, pInput->numOfRows); for (int32_t i = pInput->startRowIndex; i < pInput->numOfRows + pInput->startRowIndex; i += 1) { char* data = colDataGetData(pInputCol, i); From ede4a57c99de44d33e64ef5baddb9dc88ce835c7 Mon Sep 17 00:00:00 2001 From: Ganlin Zhao Date: Mon, 16 May 2022 19:36:04 +0800 Subject: [PATCH 5/5] enh(query): tail function handle offset param --- source/libs/function/src/builtins.c | 11 +++++++---- source/libs/function/src/builtinsimpl.c | 14 +++++++++++--- 2 files changed, 18 insertions(+), 7 deletions(-) diff --git a/source/libs/function/src/builtins.c b/source/libs/function/src/builtins.c index 51f30aca21..e41e3c7c39 100644 --- a/source/libs/function/src/builtins.c +++ b/source/libs/function/src/builtins.c @@ -387,7 +387,8 @@ static int32_t translateSample(SFunctionNode* pFunc, char* pErrBuf, int32_t len) } static int32_t translateTail(SFunctionNode* pFunc, char* pErrBuf, int32_t len) { - if (2 != LIST_LENGTH(pFunc->pParameterList)) { + int32_t numOfParams = LIST_LENGTH(pFunc->pParameterList); + if (2 != numOfParams && 3 != numOfParams) { return invaildFuncParaNumErrMsg(pErrBuf, len, pFunc->functionName); } @@ -397,9 +398,11 @@ static int32_t translateTail(SFunctionNode* pFunc, char* pErrBuf, int32_t len) { "The input parameter of TAIL function can only be column"); } - uint8_t paraType = ((SExprNode*)nodesListGetNode(pFunc->pParameterList, 1))->resType.type; - if (!IS_INTEGER_TYPE(paraType)) { - return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName); + for (int32_t i = 1; i < numOfParams; ++i) { + uint8_t paraType = ((SExprNode*)nodesListGetNode(pFunc->pParameterList, i))->resType.type; + if (!IS_INTEGER_TYPE(paraType)) { + return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName); + } } SExprNode* pCol = (SExprNode*)nodesListGetNode(pFunc->pParameterList, 0); diff --git a/source/libs/function/src/builtinsimpl.c b/source/libs/function/src/builtinsimpl.c index add33adb08..479a11ca4a 100644 --- a/source/libs/function/src/builtinsimpl.c +++ b/source/libs/function/src/builtinsimpl.c @@ -3177,7 +3177,11 @@ bool tailFunctionSetup(SqlFunctionCtx *pCtx, SResultRowEntryInfo *pResultInfo) { STailInfo *pInfo = GET_ROWCELL_INTERBUF(pResultInfo); pInfo->numAdded = 0; pInfo->numOfPoints = pCtx->param[1].param.i; - pInfo->offset = pCtx->param[2].param.i; + if (pCtx->numOfParams == 4) { + pInfo->offset = pCtx->param[2].param.i; + } else { + pInfo->offset = 0; + } pInfo->colType = pCtx->resDataInfo.type; pInfo->colBytes = pCtx->resDataInfo.bytes; if ((pInfo->numOfPoints < 1 || pInfo->numOfPoints > TAIL_MAX_POINTS_NUM) || @@ -3236,8 +3240,12 @@ int32_t tailFunction(SqlFunctionCtx* pCtx) { SColumnInfoData* pOutput = (SColumnInfoData*)pCtx->pOutput; int32_t startOffset = pCtx->offset; - pInfo->numOfPoints = MIN(pInfo->numOfPoints, pInput->numOfRows); - for (int32_t i = pInput->startRowIndex; i < pInput->numOfRows + pInput->startRowIndex; i += 1) { + if (pInfo->offset >= pInput->numOfRows) { + return 0; + } else { + pInfo->numOfPoints = MIN(pInfo->numOfPoints, pInput->numOfRows - pInfo->offset); + } + for (int32_t i = pInput->startRowIndex; i < pInput->numOfRows + pInput->startRowIndex - pInfo->offset; i += 1) { char* data = colDataGetData(pInputCol, i); doTailAdd(pInfo, data, tsList[i], colDataIsNull_s(pInputCol, i));