add top getenv function for merge function

source/libs/function/inc/builtinsimpl.h

@@ -99,6 +99,7 @@ int32_t firstCombine(SqlFunctionCtx* pDestCtx, SqlFunctionCtx* pSourceCtx);
 int32_t lastCombine(SqlFunctionCtx* pDestCtx, SqlFunctionCtx* pSourceCtx);
 
 bool getTopBotFuncEnv(SFunctionNode* UNUSED_PARAM(pFunc), SFuncExecEnv* pEnv);
+bool getTopBotMergeFuncEnv(SFunctionNode* UNUSED_PARAM(pFunc), SFuncExecEnv* pEnv);
 bool topBotFunctionSetup(SqlFunctionCtx *pCtx, SResultRowEntryInfo* pResultInfo);
 int32_t topFunction(SqlFunctionCtx *pCtx);
 int32_t topFunctionMerge(SqlFunctionCtx *pCtx);

source/libs/function/src/builtins.c

@@ -1559,7 +1559,7 @@ const SBuiltinFuncDefinition funcMgtBuiltins[] = {
     .type = FUNCTION_TYPE_TOP_MERGE,
     .classification = FUNC_MGT_AGG_FUNC | FUNC_MGT_SELECT_FUNC | FUNC_MGT_INDEFINITE_ROWS_FUNC,
     .translateFunc = translateTopBotMerge,
-    .getEnvFunc   = getTopBotFuncEnv,
+    .getEnvFunc   = getTopBotMergeFuncEnv,
     .initFunc     = functionSetup,
     .processFunc  = topFunctionMerge,
     .finalizeFunc = topBotFinalize,

source/libs/function/src/builtinsimpl.c

@@ -2661,6 +2661,12 @@ bool getTopBotFuncEnv(SFunctionNode* pFunc, SFuncExecEnv* pEnv) {
   return true;
 }
 
+bool getTopBotFuncMergeEnv(SFunctionNode* pFunc, SFuncExecEnv* pEnv) {
+  //intermediate result is binary and length contains VAR header size
+  pEnv->calcMemSize = pFunc->node.resType.bytes - VARSTR_HEADER_SIZE;
+  return true;
+}
+
 bool topBotFunctionSetup(SqlFunctionCtx* pCtx, SResultRowEntryInfo* pResInfo) {
   if (!functionSetup(pCtx, pResInfo)) {
     return false;