From 267e6e0ba6d292398eddfd09912250f2184bfcaa Mon Sep 17 00:00:00 2001
From: Haojun Liao <hjliao@taosdata.com>
Date: Wed, 8 Sep 2021 14:03:00 +0800
Subject: [PATCH] [td-255] avoid memset the allocated memory to improve the
 query performance.

---
 src/client/inc/tscUtil.h   |  4 +++-
 src/client/src/tscServer.c |  3 ++-
 src/client/src/tscUtil.c   | 30 ++++++++++++++++--------------
 3 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/src/client/inc/tscUtil.h b/src/client/inc/tscUtil.h
index cf2aadc107..c858bd5867 100644
--- a/src/client/inc/tscUtil.h
+++ b/src/client/inc/tscUtil.h
@@ -174,7 +174,9 @@ void    tscClearInterpInfo(SQueryInfo* pQueryInfo);
 
 bool tscIsInsertData(char* sqlstr);
 
-int tscAllocPayload(SSqlCmd* pCmd, int size);
+// the memory is not reset in case of fast allocate payload function
+int32_t tscAllocPayloadFast(SSqlCmd *pCmd, size_t size);
+int32_t tscAllocPayload(SSqlCmd* pCmd, int size);
 
 TAOS_FIELD tscCreateField(int8_t type, const char* name, int16_t bytes);
 
diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index b713eeb858..6133bc4a9c 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -887,8 +887,9 @@ int tscBuildQueryMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
 
   int32_t code = TSDB_CODE_SUCCESS;
   int32_t size = tscEstimateQueryMsgSize(pSql);
+  assert(size > 0);
 
-  if (TSDB_CODE_SUCCESS != tscAllocPayload(pCmd, size)) {
+  if (TSDB_CODE_SUCCESS != tscAllocPayloadFast(pCmd, size)) {
     tscError("%p failed to malloc for query msg", pSql);
     return TSDB_CODE_TSC_INVALID_OPERATION;  // todo add test for this
   }
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index a9b74ecb86..b68bf6d83a 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -2080,32 +2080,34 @@ bool tscIsInsertData(char* sqlstr) {
   } while (1);
 }
 
-int tscAllocPayload(SSqlCmd* pCmd, int size) {
+int32_t tscAllocPayloadFast(SSqlCmd *pCmd, size_t size) {
   if (pCmd->payload == NULL) {
     assert(pCmd->allocSize == 0);
 
-    pCmd->payload = (char*)calloc(1, size);
-    if (pCmd->payload == NULL) {
+    pCmd->payload = malloc(size);
+  } else if (pCmd->allocSize < size) {
+    char* tmp = realloc(pCmd->payload, size);
+    if (tmp == NULL) {
       return TSDB_CODE_TSC_OUT_OF_MEMORY;
     }
 
+    pCmd->payload = tmp;
     pCmd->allocSize = size;
-  } else {
-    if (pCmd->allocSize < (uint32_t)size) {
-      char* b = realloc(pCmd->payload, size);
-      if (b == NULL) {
-        return TSDB_CODE_TSC_OUT_OF_MEMORY;
-      }
+  }
 
-      pCmd->payload = b;
-      pCmd->allocSize = size;
-    }
+  assert(pCmd->allocSize >= size);
+  return TSDB_CODE_SUCCESS;
+}
+
+int32_t tscAllocPayload(SSqlCmd* pCmd, int size) {
+  assert(size > 0);
 
+  int32_t code = tscAllocPayloadFast(pCmd, (size_t) size);
+  if (code == TSDB_CODE_SUCCESS) {
     memset(pCmd->payload, 0, pCmd->allocSize);
   }
 
-  assert(pCmd->allocSize >= (uint32_t)size && size > 0);
-  return TSDB_CODE_SUCCESS;
+  return code;
 }
 
 TAOS_FIELD tscCreateField(int8_t type, const char* name, int16_t bytes) {
-- 
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