diff --git a/source/libs/function/inc/builtinsimpl.h b/source/libs/function/inc/builtinsimpl.h
index c488abc1987488064440cd3ba472eac6dbb15039..0bc6076a8883d1cf8d8a12d64177c8e631b5152c 100644
--- a/source/libs/function/inc/builtinsimpl.h
+++ b/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);
diff --git a/source/libs/function/src/builtins.c b/source/libs/function/src/builtins.c
index 701f5a1a269bea31893565e9a73bd74371462aa5..be879b08c0b3e00063c01d9c9d957d3bdc91ef88 100644
--- a/source/libs/function/src/builtins.c
+++ b/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,
diff --git a/source/libs/function/src/builtinsimpl.c b/source/libs/function/src/builtinsimpl.c
index b37b668aac0378fcbe73784a91bd8c9b59ec133d..25d9284314f44fafdc9a9d2ca0ecc39b4c4507a8 100644
--- a/source/libs/function/src/builtinsimpl.c
+++ b/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;