diff --git a/source/dnode/vnode/src/tsdb/tsdbMergeTree.c b/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
index e6210ff659513bf7dfef60b17c768773a9a539ad..d660dfa99dba2ceaa7257d131fb960e9d97b1457 100644
--- a/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
+++ b/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
@@ -124,7 +124,7 @@ static SBlockData* loadBlockIfMissing(SLDataIter *pIter) {
 static FORCE_INLINE int32_t findEarliestIndex(int32_t index, uint64_t uid, const SSttBlk* pBlockList, int32_t num, int32_t backward) {
   int32_t i = index;
   int32_t step = backward? 1:-1;
-  while (uid >= pBlockList[i].minUid && uid <= pBlockList[i].maxUid && i >= 0 && i < num) {
+  while (i >= 0 && i < num && uid >= pBlockList[i].minUid && uid <= pBlockList[i].maxUid) {
     i += step;
   }
   return i - step;
@@ -169,7 +169,7 @@ static int32_t binarySearchForStartBlock(SSttBlk*pBlockList, int32_t num, uint64
 static FORCE_INLINE int32_t findEarliestRow(int32_t index, uint64_t uid, const uint64_t* uidList, int32_t num, int32_t backward) {
   int32_t i = index;
   int32_t step = backward? 1:-1;
-  while (uid == uidList[i] && i >= 0 && i < num) {
+  while (i >= 0 && i < num && uid == uidList[i]) {
     i += step;
   }
   return i - step;
diff --git a/source/dnode/vnode/src/tsdb/tsdbRead.c b/source/dnode/vnode/src/tsdb/tsdbRead.c
index d3053ca2b1fe53230a6e359fa230d07089811fbd..8229751d3c4f4aaa24925a9a44549f659d27687e 100644
--- a/source/dnode/vnode/src/tsdb/tsdbRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbRead.c
@@ -3256,11 +3256,18 @@ int32_t tsdbReaderOpen(SVnode* pVnode, SQueryTableDataCond* pCond, SArray* pTabl
     }
   }
 
+  // NOTE: the endVersion in pCond is the data version not schema version, so pCond->endVersion is not correct here.
   if (pCond->suid != 0) {
-    pReader->pSchema = metaGetTbTSchema(pReader->pTsdb->pVnode->pMeta, pReader->suid, pCond->endVersion);
+    pReader->pSchema = metaGetTbTSchema(pReader->pTsdb->pVnode->pMeta, pReader->suid, /*pCond->endVersion*/ -1);
+    if (pReader->pSchema == NULL) {
+      tsdbError("failed to get table schema, suid:%"PRIu64", ver:%"PRId64" , %s", pReader->suid, -1, pReader->idStr);
+    }
   } else if (taosArrayGetSize(pTableList) > 0) {
     STableKeyInfo* pKey = taosArrayGet(pTableList, 0);
-    pReader->pSchema = metaGetTbTSchema(pReader->pTsdb->pVnode->pMeta, pKey->uid, pCond->endVersion);
+    pReader->pSchema = metaGetTbTSchema(pReader->pTsdb->pVnode->pMeta, pKey->uid, /*pCond->endVersion*/ -1);
+    if (pReader->pSchema == NULL) {
+      tsdbError("failed to get table schema, uid:%"PRIu64", ver:%"PRId64" , %s", pKey->uid, -1, pReader->idStr);
+    }
   }
 
   int32_t numOfTables = taosArrayGetSize(pTableList);