fix: row schema version for row merger

source/dnode/vnode/src/tsdb/tsdbRead.c

@@ -1758,11 +1758,14 @@ static int32_t doMergeBufAndFileRows(STsdbReader* pReader, STableBlockScanInfo*
     }
 
     if (minKey == k.ts) {
+      STSchema* pSchema = doGetSchemaForTSRow(TSDBROW_SVERSION(pRow), pReader, pBlockScanInfo->uid);
+      if (pSchema == NULL) {
+        return terrno;
+      }
       if (init) {
-        tRowMerge(&merge, pRow);
+        tRowMergerAdd(&merge, pRow, pSchema);
       } else {
         init = true;
-        STSchema* pSchema = doGetSchemaForTSRow(TSDBROW_SVERSION(pRow), pReader, pBlockScanInfo->uid);
         int32_t   code = tRowMergerInit(&merge, pRow, pSchema);
         if (code != TSDB_CODE_SUCCESS) {
           return code;