builtins.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 "builtins.h"
#include "builtinsimpl.h"
#include "scalar.h"
#include "taoserror.h"
#include "tdatablock.h"

int32_t checkAndGetResultType(SFunctionNode* pFunc);

const SBuiltinFuncDefinition funcMgtBuiltins[] = {
  {
    .name = "count",
    .type = FUNCTION_TYPE_COUNT,
    .classification = FUNC_MGT_AGG_FUNC | FUNC_MGT_SPECIAL_DATA_REQUIRED,
    .checkFunc    = checkAndGetResultType,
    .dataRequiredFunc = countDataRequired,
    .getEnvFunc   = getCountFuncEnv,
    .initFunc     = functionSetup,
    .processFunc  = countFunction,
    .finalizeFunc = functionFinalize
  },
  {
    .name = "sum",
    .type = FUNCTION_TYPE_SUM,
    .classification = FUNC_MGT_AGG_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getSumFuncEnv,
    .initFunc     = functionSetup,
    .processFunc  = sumFunction,
    .finalizeFunc = functionFinalize
  },
  {
    .name = "min",
    .type = FUNCTION_TYPE_MIN,
    .classification = FUNC_MGT_AGG_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getMinmaxFuncEnv,
    .initFunc     = minFunctionSetup,
    .processFunc  = minFunction,
    .finalizeFunc = functionFinalize
  },
  {
    .name = "max",
    .type = FUNCTION_TYPE_MAX,
    .classification = FUNC_MGT_AGG_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getMinmaxFuncEnv,
    .initFunc     = maxFunctionSetup,
    .processFunc  = maxFunction,
    .finalizeFunc = functionFinalize
  },
  {
    .name = "stddev",
    .type = FUNCTION_TYPE_STDDEV,
    .classification = FUNC_MGT_AGG_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getStddevFuncEnv,
    .initFunc     = stddevFunctionSetup,
    .processFunc  = stddevFunction,
    .finalizeFunc = stddevFinalize
  },
  {
    .name = "percentile",
    .type = FUNCTION_TYPE_PERCENTILE,
    .classification = FUNC_MGT_AGG_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getPercentileFuncEnv,
    .initFunc     = percentileFunctionSetup,
    .processFunc  = percentileFunction,
    .finalizeFunc = percentileFinalize
  },
  {
    .name = "apercentile",
    .type = FUNCTION_TYPE_APERCENTILE,
    .classification = FUNC_MGT_AGG_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getMinmaxFuncEnv,
    .initFunc     = maxFunctionSetup,
    .processFunc  = maxFunction,
    .finalizeFunc = functionFinalize
  },
  {
    .name = "top",
    .type = FUNCTION_TYPE_TOP,
    .classification = FUNC_MGT_AGG_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getMinmaxFuncEnv,
    .initFunc     = maxFunctionSetup,
    .processFunc  = maxFunction,
    .finalizeFunc = functionFinalize
  },
  {
    .name = "bottom",
    .type = FUNCTION_TYPE_BOTTOM,
    .classification = FUNC_MGT_AGG_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getMinmaxFuncEnv,
    .initFunc     = maxFunctionSetup,
    .processFunc  = maxFunction,
    .finalizeFunc = functionFinalize
  },
  {
    .name = "spread",
    .type = FUNCTION_TYPE_SPREAD,
    .classification = FUNC_MGT_AGG_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getMinmaxFuncEnv,
    .initFunc     = maxFunctionSetup,
    .processFunc  = maxFunction,
    .finalizeFunc = functionFinalize
  },
  {
    .name = "last_row",
    .type = FUNCTION_TYPE_LAST_ROW,
    .classification = FUNC_MGT_AGG_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getMinmaxFuncEnv,
    .initFunc     = maxFunctionSetup,
    .processFunc  = maxFunction,
    .finalizeFunc = functionFinalize
  },
  {
    .name = "first",
    .type = FUNCTION_TYPE_FIRST,
    .classification = FUNC_MGT_AGG_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getFirstLastFuncEnv,
    .initFunc     = functionSetup,
    .processFunc  = firstFunction,
    .finalizeFunc = functionFinalize
  },
  {
    .name = "last",
    .type = FUNCTION_TYPE_LAST,
    .classification = FUNC_MGT_AGG_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getFirstLastFuncEnv,
    .initFunc     = functionSetup,
    .processFunc  = lastFunction,
    .finalizeFunc = functionFinalize
  },
  {
    .name = "diff",
    .type = FUNCTION_TYPE_DIFF,
    .classification = FUNC_MGT_NONSTANDARD_SQL_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getDiffFuncEnv,
    .initFunc     = diffFunctionSetup,
    .processFunc  = diffFunction,
    .finalizeFunc = functionFinalize
  },
  {
    .name = "abs",
    .type = FUNCTION_TYPE_ABS,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = absFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "log",
    .type = FUNCTION_TYPE_LOG,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = logFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "pow",
    .type = FUNCTION_TYPE_POW,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = powFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "sqrt",
    .type = FUNCTION_TYPE_SQRT,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = sqrtFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "ceil",
    .type = FUNCTION_TYPE_CEIL,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = ceilFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "floor",
    .type = FUNCTION_TYPE_FLOOR,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = floorFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "round",
    .type = FUNCTION_TYPE_ROUND,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = roundFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "sin",
    .type = FUNCTION_TYPE_SIN,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = sinFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "cos",
    .type = FUNCTION_TYPE_COS,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = cosFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "tan",
    .type = FUNCTION_TYPE_TAN,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = tanFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "asin",
    .type = FUNCTION_TYPE_ASIN,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = asinFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "acos",
    .type = FUNCTION_TYPE_ACOS,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = acosFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "atan",
    .type = FUNCTION_TYPE_ATAN,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = atanFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "length",
    .type = FUNCTION_TYPE_LENGTH,
    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_STRING_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = lengthFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "char_length",
    .type = FUNCTION_TYPE_CHAR_LENGTH,
    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_STRING_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = charLengthFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "concat",
    .type = FUNCTION_TYPE_CONCAT,
    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_STRING_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = concatFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "concat_ws",
    .type = FUNCTION_TYPE_CONCAT_WS,
    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_STRING_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = concatWsFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "lower",
    .type = FUNCTION_TYPE_LOWER,
    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_STRING_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = lowerFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "upper",
    .type = FUNCTION_TYPE_UPPER,
    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_STRING_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = upperFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "ltrim",
    .type = FUNCTION_TYPE_LTRIM,
    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_STRING_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = ltrimFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "rtrim",
    .type = FUNCTION_TYPE_RTRIM,
    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_STRING_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = rtrimFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "substr",
    .type = FUNCTION_TYPE_SUBSTR,
    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_STRING_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = substrFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "cast",
    .type = FUNCTION_TYPE_CAST,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = castFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "to_iso8601",
    .type = FUNCTION_TYPE_TO_ISO8601,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = toISO8601Function,
    .finalizeFunc = NULL
  },
  {
    .name = "to_unixtimestamp",
    .type = FUNCTION_TYPE_TO_UNIXTIMESTAMP,
    .classification = FUNC_MGT_SCALAR_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = toUnixtimestampFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "_rowts",
    .type = FUNCTION_TYPE_ROWTS,
    .classification = FUNC_MGT_PSEUDO_COLUMN_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getTimePseudoFuncEnv,
    .initFunc     = NULL,
    .sprocessFunc = NULL,
    .finalizeFunc = NULL
  },
  {
    .name = "tbname",
    .type = FUNCTION_TYPE_TBNAME,
    .classification = FUNC_MGT_PSEUDO_COLUMN_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = NULL,
    .initFunc     = NULL,
    .sprocessFunc = NULL,
    .finalizeFunc = NULL
  },
  {
    .name = "_qstartts",
    .type = FUNCTION_TYPE_QSTARTTS,
    .classification = FUNC_MGT_PSEUDO_COLUMN_FUNC | FUNC_MGT_WINDOW_PC_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getTimePseudoFuncEnv,
    .initFunc     = NULL,
    .sprocessFunc = qStartTsFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "_qendts",
    .type = FUNCTION_TYPE_QENDTS,
    .classification = FUNC_MGT_PSEUDO_COLUMN_FUNC | FUNC_MGT_WINDOW_PC_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getTimePseudoFuncEnv,
    .initFunc     = NULL,
    .sprocessFunc = qEndTsFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "_wstartts",
    .type = FUNCTION_TYPE_WSTARTTS,
    .classification = FUNC_MGT_PSEUDO_COLUMN_FUNC | FUNC_MGT_WINDOW_PC_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getTimePseudoFuncEnv,
    .initFunc     = NULL,
    .sprocessFunc = winStartTsFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "_wendts",
    .type = FUNCTION_TYPE_QENDTS,
    .classification = FUNC_MGT_PSEUDO_COLUMN_FUNC | FUNC_MGT_WINDOW_PC_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getTimePseudoFuncEnv,
    .initFunc     = NULL,
    .sprocessFunc = winEndTsFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "_wduration",
    .type = FUNCTION_TYPE_WDURATION,
    .classification = FUNC_MGT_PSEUDO_COLUMN_FUNC | FUNC_MGT_WINDOW_PC_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getTimePseudoFuncEnv,
    .initFunc     = NULL,
    .sprocessFunc = winDurFunction,
    .finalizeFunc = NULL
  },
  {
    .name = "now",
    .type = FUNCTION_TYPE_NOW,
    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_DATETIME_FUNC,
    .checkFunc    = checkAndGetResultType,
    .getEnvFunc   = getTimePseudoFuncEnv,
    .initFunc     = NULL,
    .sprocessFunc = winDurFunction,
    .finalizeFunc = NULL
  }
};

const int32_t funcMgtBuiltinsNum = (sizeof(funcMgtBuiltins) / sizeof(SBuiltinFuncDefinition));

int32_t checkAndGetResultType(SFunctionNode* pFunc) {
  switch(pFunc->funcType) {
    case FUNCTION_TYPE_WDURATION:
    case FUNCTION_TYPE_COUNT: {
      pFunc->node.resType = (SDataType){.bytes = sizeof(int64_t), .type = TSDB_DATA_TYPE_BIGINT};
      break;
    }

    case FUNCTION_TYPE_SUM: {
      SColumnNode* pParam = nodesListGetNode(pFunc->pParameterList, 0);
      int32_t paraType = pParam->node.resType.type;

      int32_t resType  = 0;
      if (IS_SIGNED_NUMERIC_TYPE(paraType) || paraType == TSDB_DATA_TYPE_BOOL) {
        resType = TSDB_DATA_TYPE_BIGINT;
      } else if (IS_UNSIGNED_NUMERIC_TYPE(paraType)) {
        resType = TSDB_DATA_TYPE_UBIGINT;
      } else if (IS_FLOAT_TYPE(paraType)) {
        resType = TSDB_DATA_TYPE_DOUBLE;
      } else {
        ASSERT(0);
      }

      pFunc->node.resType = (SDataType) { .bytes = tDataTypes[resType].bytes, .type = resType };
      break;
    }

    case FUNCTION_TYPE_DIFF:
    case FUNCTION_TYPE_FIRST:
    case FUNCTION_TYPE_LAST:
    case FUNCTION_TYPE_MIN:
    case FUNCTION_TYPE_MAX: {
      SColumnNode* pParam = nodesListGetNode(pFunc->pParameterList, 0);
      int32_t paraType = pParam->node.resType.type;
      pFunc->node.resType = (SDataType) { .bytes = tDataTypes[paraType].bytes, .type = paraType };
      break;
    }

    case FUNCTION_TYPE_ROWTS:
    case FUNCTION_TYPE_QSTARTTS:
    case FUNCTION_TYPE_QENDTS:
    case FUNCTION_TYPE_WSTARTTS:
    case FUNCTION_TYPE_WENDTS:{
      pFunc->node.resType = (SDataType){.bytes = sizeof(int64_t), .type = TSDB_DATA_TYPE_TIMESTAMP};
      break;
    }

    case FUNCTION_TYPE_ABS:
    case FUNCTION_TYPE_CEIL:
    case FUNCTION_TYPE_FLOOR:
    case FUNCTION_TYPE_ROUND: {
      SColumnNode* pParam = nodesListGetNode(pFunc->pParameterList, 0);
      int32_t paraType = pParam->node.resType.type;
      pFunc->node.resType = (SDataType) { .bytes = tDataTypes[paraType].bytes, .type = paraType };
      break;
    }

    case FUNCTION_TYPE_PERCENTILE:
    case FUNCTION_TYPE_STDDEV:
    case FUNCTION_TYPE_SIN:
    case FUNCTION_TYPE_COS:
    case FUNCTION_TYPE_TAN:
    case FUNCTION_TYPE_ASIN:
    case FUNCTION_TYPE_ACOS:
    case FUNCTION_TYPE_ATAN:
    case FUNCTION_TYPE_SQRT:
    case FUNCTION_TYPE_LOG:
    case FUNCTION_TYPE_POW: {
      pFunc->node.resType = (SDataType) { .bytes = tDataTypes[TSDB_DATA_TYPE_DOUBLE].bytes, .type = TSDB_DATA_TYPE_DOUBLE };
      break;
    }

    case FUNCTION_TYPE_LENGTH:
    case FUNCTION_TYPE_CHAR_LENGTH: {
      pFunc->node.resType = (SDataType) { .bytes = tDataTypes[TSDB_DATA_TYPE_SMALLINT].bytes, .type = TSDB_DATA_TYPE_SMALLINT };
      break;
    }

    case FUNCTION_TYPE_CONCAT:
    case FUNCTION_TYPE_CONCAT_WS: {
      int32_t paraType, paraBytes = 0;
      bool typeSet = false;
      for (int32_t i = 0; i < pFunc->pParameterList->length; ++i) {
        SColumnNode* pParam = nodesListGetNode(pFunc->pParameterList, i);
        if (pParam->node.type == QUERY_NODE_COLUMN) {
          if (typeSet == false) {
            paraType = pParam->node.resType.type;
            typeSet = true;
          } else {
            //columns have to be the same type
            if (paraType != pParam->node.resType.type) {
              return TSDB_CODE_FAILED;
            }
          }
          paraBytes += pParam->node.resType.bytes;
        }
      }

      for (int32_t i = 0; i < pFunc->pParameterList->length; ++i) {
        SColumnNode* pParam = nodesListGetNode(pFunc->pParameterList, i);
        if (pParam->node.type == QUERY_NODE_VALUE) {
          if (paraType == TSDB_DATA_TYPE_NCHAR) {
            paraBytes += pParam->node.resType.bytes * TSDB_NCHAR_SIZE;
          } else {
            paraBytes += pParam->node.resType.bytes;
          }
        }
      }
      pFunc->node.resType = (SDataType) { .bytes = paraBytes, .type = paraType };
      break;
    }
    case FUNCTION_TYPE_LOWER:
    case FUNCTION_TYPE_UPPER:
    case FUNCTION_TYPE_LTRIM:
    case FUNCTION_TYPE_RTRIM:
    case FUNCTION_TYPE_SUBSTR: {
      SColumnNode* pParam = nodesListGetNode(pFunc->pParameterList, 0);
      int32_t paraType  = pParam->node.resType.type;
      int32_t paraBytes = pParam->node.resType.bytes;
      pFunc->node.resType = (SDataType) { .bytes = paraBytes, .type = paraType };
      break;
    }
    case FUNCTION_TYPE_CAST: {
      //type
      SValueNode* pParam = nodesListGetNode(pFunc->pParameterList, 1);
      int32_t paraType = pParam->datum.i;
      //bytes
      pParam = nodesListGetNode(pFunc->pParameterList, 2);
      int32_t paraBytes = pParam->datum.i;
      pFunc->node.resType = (SDataType) { .bytes = paraBytes, .type = paraType};
      break;
    }
    case FUNCTION_TYPE_TO_ISO8601: {
      pFunc->node.resType = (SDataType) { .bytes = 64, .type = TSDB_DATA_TYPE_BINARY};
    }
    case FUNCTION_TYPE_TO_UNIXTIMESTAMP: {
      pFunc->node.resType = (SDataType) { .bytes = tDataTypes[TSDB_DATA_TYPE_BIGINT].bytes, .type = TSDB_DATA_TYPE_BIGINT};
    }

    case FUNCTION_TYPE_TBNAME: {
      // todo
      break;
    }

    case FUNCTION_TYPE_NOW:
      // todo
      break;
    default:
      ASSERT(0); // to found the fault ASAP.
  }

  return TSDB_CODE_SUCCESS;
}