diff --git a/src/client/src/tscProfile.c b/src/client/src/tscProfile.c
index ee89b5f580cd7e66205c3c9dcfd0c2b7fe5c0cf2..8585a3dac7402cd9a1d4702dcd47b6725270f87e 100644
--- a/src/client/src/tscProfile.c
+++ b/src/client/src/tscProfile.c
@@ -89,12 +89,22 @@ void tscSaveSlowQueryFp(void *handle, void *tmrId) {
 
 void tscSaveSlowQuery(SSqlObj *pSql) {
   const static int64_t SLOW_QUERY_INTERVAL = 3000000L;
-  if (pSql->res.useconds < SLOW_QUERY_INTERVAL) return;
+  size_t size = 200;  // other part of sql string, expect the main sql str
+  
+  if (pSql->res.useconds < SLOW_QUERY_INTERVAL) {
+    return;
+  }
 
   tscTrace("%p query time:%" PRId64 " sql:%s", pSql, pSql->res.useconds, pSql->sqlstr);
-
-  char *sql = malloc(200);
-  int   len = snprintf(sql, 190, "insert into %s.slowquery values(now, '%s', %" PRId64 ", %" PRId64 ", '", tsMonitorDbName,
+  int32_t sqlSize = TSDB_SHOW_SQL_LEN + size;
+  
+  char *sql = malloc(sqlSize);
+  if (sql == NULL) {
+    tscError("%p failed to allocate memory to sent slow to dnode", pSql);
+    return;
+  }
+  
+  int len = snprintf(sql, size, "insert into %s.slowquery values(now, '%s', %" PRId64 ", %" PRId64 ", '", tsMonitorDbName,
           pSql->pTscObj->user, pSql->stime, pSql->res.useconds);
   int sqlLen = snprintf(sql + len, TSDB_SHOW_SQL_LEN, "%s", pSql->sqlstr);
   if (sqlLen > TSDB_SHOW_SQL_LEN - 1) {