From 551a65e16108deef13dd5149459bfbb080f0f5d9 Mon Sep 17 00:00:00 2001
From: factosea <285808407@qq.com>
Date: Thu, 29 Feb 2024 10:44:25 +0800
Subject: [PATCH] fix: varmeta length reset

---
 source/common/src/tdatablock.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/source/common/src/tdatablock.c b/source/common/src/tdatablock.c
index 6b6c3642de..a20ecd344d 100644
--- a/source/common/src/tdatablock.c
+++ b/source/common/src/tdatablock.c
@@ -1688,17 +1688,19 @@ int32_t blockDataTrimFirstRows(SSDataBlock* pBlock, size_t n) {
 }
 
 static void colDataKeepFirstNRows(SColumnInfoData* pColInfoData, size_t n, size_t total) {
+  if (n >= total || n == 0) return;
   if (IS_VAR_DATA_TYPE(pColInfoData->info.type)) {
-    int32_t newLen = pColInfoData->varmeta.offset[n - 1];
-    if (newLen != -1) {
-      if (pColInfoData->info.type == TSDB_DATA_TYPE_JSON) {
-        newLen += getJsonValueLen(pColInfoData->pData + newLen);
-      } else {
-        newLen += varDataTLen(pColInfoData->pData + newLen);
+    int32_t newLen = -1;
+    for (int i = n; i >= 0; --i) {
+      if (pColInfoData->varmeta.offset[i] != -1) {
+        newLen = pColInfoData->varmeta.offset[i];
+        break;
       }
-    } else {
-      newLen = pColInfoData->varmeta.length;
     }
+    if(-1 == newLen) {
+      return;
+    }
+
     pColInfoData->varmeta.length = newLen;
     // pColInfoData->varmeta.length = colDataMoveVarData(pColInfoData, 0, n);
     memset(&pColInfoData->varmeta.offset[n], 0, total - n);