fix(query): set the table schema correctly when the table is dropped.

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

@@ -1881,8 +1881,8 @@ static FORCE_INLINE STSchema* getLatestTableSchema(STsdbReader* pReader, uint64_
     return pReader->pSchema;
   }
 
-  pReader->pSchema = metaGetTbTSchema(pReader->pTsdb->pVnode->pMeta, uid, -1, 1);
-  if (pReader->pSchema == NULL) {
+  int32_t code = metaGetTbTSchemaEx(pReader->pTsdb->pVnode->pMeta, uid, -1, 1, &pReader->pSchema);
+  if (code != TSDB_CODE_SUCCESS || pReader->pSchema == NULL) {
     tsdbError("failed to get table schema, uid:%" PRIu64 ", it may have been dropped, ver:-1, %s", uid, pReader->idStr);
   }
 
@@ -1890,9 +1890,15 @@ static FORCE_INLINE STSchema* getLatestTableSchema(STsdbReader* pReader, uint64_
 }
 
 static FORCE_INLINE STSchema* doGetSchemaForTSRow(int32_t sversion, STsdbReader* pReader, uint64_t uid) {
+  int32_t code = 0;
+
   // always set the newest schema version in pReader->pSchema
   if (pReader->pSchema == NULL) {
-    pReader->pSchema = metaGetTbTSchema(pReader->pTsdb->pVnode->pMeta, uid, -1, 1);
+    code = metaGetTbTSchemaEx(pReader->pTsdb->pVnode->pMeta, uid, -1, 1, &pReader->pSchema);
+    if (code != TSDB_CODE_SUCCESS) {
+      terrno = code;
+      return NULL;
+    }
   }
 
   if (pReader->pSchema && sversion == pReader->pSchema->version) {
@@ -1905,7 +1911,7 @@ static FORCE_INLINE STSchema* doGetSchemaForTSRow(int32_t sversion, STsdbReader*
   }
 
   STSchema* ptr = NULL;
-  int32_t   code = metaGetTbTSchemaEx(pReader->pTsdb->pVnode->pMeta, pReader->suid, uid, sversion, &ptr);
+  code = metaGetTbTSchemaEx(pReader->pTsdb->pVnode->pMeta, pReader->suid, uid, sversion, &ptr);
   if (code != TSDB_CODE_SUCCESS) {
     terrno = code;
     return NULL;
@@ -2014,6 +2020,10 @@ static int32_t doMergeBufAndFileRows(STsdbReader* pReader, STableBlockScanInfo*
     if (minKey == k.ts) {
       init = true;
       STSchema* pSchema = doGetSchemaForTSRow(TSDBROW_SVERSION(pRow), pReader, pBlockScanInfo->uid);
+      if (pSchema == NULL) {
+        return terrno;
+      }
+
       int32_t   code = tsdbRowMergerInit(&merge, NULL, pRow, pSchema);
       if (code != TSDB_CODE_SUCCESS) {
         return code;
@@ -2222,6 +2232,7 @@ static int32_t doMergeMultiLevelRows(STsdbReader* pReader, STableBlockScanInfo*
   if (pSchema == NULL) {
     return code;
   }
+
   STSchema* piSchema = doGetSchemaForTSRow(TSDBROW_SVERSION(piRow), pReader, pBlockScanInfo->uid);
   if (piSchema == NULL) {
     return code;
@@ -3843,11 +3854,8 @@ int32_t doMergeMemTableMultiRows(TSDBROW* pRow, uint64_t uid, SIterInfo* pIter,
       return terrno;
     }
 
-    if (pReader->pSchema == NULL) {
-      pReader->pSchema = pTSchema;
-    }
-
-    code = tsdbRowMergerInit(&merge, pReader->pSchema, &current, pTSchema);
+    STSchema* ps = (pReader->pSchema != NULL)? pReader->pSchema:pTSchema;
+    code = tsdbRowMergerInit(&merge, ps, &current, pTSchema);
     if (code != TSDB_CODE_SUCCESS) {
       return code;
     }
@@ -3891,7 +3899,14 @@ int32_t doMergeMemIMemRows(TSDBROW* pRow, TSDBROW* piRow, STableBlockScanInfo* p
   TSDBKEY   k = TSDBROW_KEY(pRow);
   TSDBKEY   ik = TSDBROW_KEY(piRow);
   STSchema* pSchema = doGetSchemaForTSRow(TSDBROW_SVERSION(pRow), pReader, pBlockScanInfo->uid);
+  if (pSchema == NULL) {
+    return terrno;
+  }
+
   STSchema* piSchema = doGetSchemaForTSRow(TSDBROW_SVERSION(piRow), pReader, pBlockScanInfo->uid);
+  if (piSchema == NULL) {
+    return terrno;
+  }
 
   if (ASCENDING_TRAVERSE(pReader->order)) {  // ascending order imem --> mem
     int32_t code = tsdbRowMergerInit(&merge, pSchema, piRow, piSchema);
@@ -4000,10 +4015,11 @@ int32_t doAppendRowFromTSRow(SSDataBlock* pBlock, STsdbReader* pReader, SRow* pT
   int64_t uid = pScanInfo->uid;
   int32_t code = TSDB_CODE_SUCCESS;
 
-  int32_t numOfCols = (int32_t)taosArrayGetSize(pBlock->pDataBlock);
-
   SBlockLoadSuppInfo* pSupInfo = &pReader->suppInfo;
   STSchema*           pSchema = doGetSchemaForTSRow(pTSRow->sver, pReader, uid);
+  if (pSchema == NULL) {
+    return terrno;
+  }
 
   SColVal colVal = {0};
   int32_t i = 0, j = 0;
@@ -5187,8 +5203,6 @@ int64_t tsdbGetNumOfRowsInMemTable(STsdbReader* pReader) {
 }
 
 int32_t tsdbGetTableSchema(SVnode* pVnode, int64_t uid, STSchema** pSchema, int64_t* suid) {
-  int32_t sversion = 1;
-
   SMetaReader mr = {0};
   metaReaderInit(&mr, pVnode->pMeta, 0);
   int32_t code = metaGetTableEntryByUidCache(&mr, uid);
@@ -5200,6 +5214,7 @@ int32_t tsdbGetTableSchema(SVnode* pVnode, int64_t uid, STSchema** pSchema, int6
 
   *suid = 0;
 
+  // only child table and ordinary table is allowed, super table is not allowed.
   if (mr.me.type == TSDB_CHILD_TABLE) {
     tDecoderClear(&mr.coder);
     *suid = mr.me.ctbEntry.suid;
@@ -5209,9 +5224,7 @@ int32_t tsdbGetTableSchema(SVnode* pVnode, int64_t uid, STSchema** pSchema, int6
       metaReaderClear(&mr);
       return terrno;
     }
-    sversion = mr.me.stbEntry.schemaRow.version;
-  } else if (mr.me.type == TSDB_NORMAL_TABLE) {
-    sversion = mr.me.ntbEntry.schemaRow.version;
+  } else if (mr.me.type == TSDB_NORMAL_TABLE) {  // do nothing
   } else {
     terrno = TSDB_CODE_INVALID_PARA;
     metaReaderClear(&mr);
@@ -5219,9 +5232,10 @@ int32_t tsdbGetTableSchema(SVnode* pVnode, int64_t uid, STSchema** pSchema, int6
   }
 
   metaReaderClear(&mr);
-  *pSchema = metaGetTbTSchema(pVnode->pMeta, uid, sversion, 1);
 
-  return TSDB_CODE_SUCCESS;
+  // get the newest table schema version
+  code = metaGetTbTSchemaEx(pVnode->pMeta, uid, -1, 1, pSchema);
+  return code;
 }
 
 int32_t tsdbTakeReadSnap(STsdbReader* pReader, _query_reseek_func_t reseek, STsdbReadSnap** ppSnap) {