From 6cbedc5d4a7fe802dba7b273daff192444452b88 Mon Sep 17 00:00:00 2001
From: Haojun Liao <hjliao@taosdata.com>
Date: Mon, 15 May 2023 10:45:01 +0800
Subject: [PATCH] refactor: do some internal refactor.

---
 source/dnode/vnode/src/tq/tqRead.c | 102 ++++++++++++++++-------------
 1 file changed, 55 insertions(+), 47 deletions(-)

diff --git a/source/dnode/vnode/src/tq/tqRead.c b/source/dnode/vnode/src/tq/tqRead.c
index 1fbdb25528..ed5d7d4516 100644
--- a/source/dnode/vnode/src/tq/tqRead.c
+++ b/source/dnode/vnode/src/tq/tqRead.c
@@ -503,6 +503,55 @@ int32_t tqMaskBlock(SSchemaWrapper* pDst, SSDataBlock* pBlock, const SSchemaWrap
   return 0;
 }
 
+static int32_t buildResSDataBlock(SSDataBlock* pBlock, SSchemaWrapper* pSchema, const SArray* pColIdList) {
+  if (blockDataGetNumOfCols(pBlock) > 0) {
+    return TSDB_CODE_SUCCESS;
+  }
+
+  int32_t numOfCols = taosArrayGetSize(pColIdList);
+
+  if (numOfCols == 0) {  // all columns are required
+    for (int32_t i = 0; i < pSchema->nCols; ++i) {
+      SSchema*        pColSchema = &pSchema->pSchema[i];
+      SColumnInfoData colInfo = createColumnInfoData(pColSchema->type, pColSchema->bytes, pColSchema->colId);
+
+      int32_t code = blockDataAppendColInfo(pBlock, &colInfo);
+      if (code != TSDB_CODE_SUCCESS) {
+        blockDataFreeRes(pBlock);
+        return TSDB_CODE_OUT_OF_MEMORY;
+      }
+    }
+  } else {
+    if (numOfCols > pSchema->nCols) {
+      numOfCols = pSchema->nCols;
+    }
+
+    int32_t i = 0;
+    int32_t j = 0;
+    while (i < pSchema->nCols && j < numOfCols) {
+      SSchema* pColSchema = &pSchema->pSchema[i];
+      col_id_t colIdSchema = pColSchema->colId;
+
+      col_id_t colIdNeed = *(col_id_t*)taosArrayGet(pColIdList, j);
+      if (colIdSchema < colIdNeed) {
+        i++;
+      } else if (colIdSchema > colIdNeed) {
+        j++;
+      } else {
+        SColumnInfoData colInfo = createColumnInfoData(pColSchema->type, pColSchema->bytes, pColSchema->colId);
+        int32_t         code = blockDataAppendColInfo(pBlock, &colInfo);
+        if (code != TSDB_CODE_SUCCESS) {
+          return -1;
+        }
+        i++;
+        j++;
+      }
+    }
+  }
+
+  return TSDB_CODE_SUCCESS;
+}
+
 int32_t tqRetrieveDataBlock(STqReader* pReader, SSubmitTbData** pSubmitTbDataRet) {
   tqDebug("tq reader retrieve data block %p, index:%d", pReader->msg.msgStr, pReader->nextBlk);
 
@@ -534,57 +583,16 @@ int32_t tqRetrieveDataBlock(STqReader* pReader, SSubmitTbData** pSubmitTbDataRet
       return -1;
     }
 
+    ASSERT(pReader->cachedSchemaVer == pReader->pSchemaWrapper->version);
+
     pReader->cachedSchemaUid = uid;
     pReader->cachedSchemaSuid = suid;
     pReader->cachedSchemaVer = sversion;
 
-    SSchemaWrapper* pSchemaWrapper = pReader->pSchemaWrapper;
-    if (blockDataGetNumOfCols(pBlock) > 0) {
-      blockDataDestroy(pReader->pResBlock);
-      pReader->pResBlock = createDataBlock();
-      pBlock = pReader->pResBlock;
-
-      pBlock->info.id.uid = uid;
-      pBlock->info.version = pReader->msg.ver;
-    }
-
-    int32_t numOfCols = taosArrayGetSize(pReader->pColIdList);
-    if (numOfCols == 0) {  // all columns are required
-      for (int32_t i = 0; i < pSchemaWrapper->nCols; ++i) {
-        SSchema*        pColSchema = &pSchemaWrapper->pSchema[i];
-        SColumnInfoData colInfo = createColumnInfoData(pColSchema->type, pColSchema->bytes, pColSchema->colId);
-
-        int32_t code = blockDataAppendColInfo(pBlock, &colInfo);
-        if (code != TSDB_CODE_SUCCESS) {
-          blockDataFreeRes(pBlock);
-          return -1;
-        }
-      }
-    } else {
-      if (numOfCols > pSchemaWrapper->nCols) {
-        numOfCols = pSchemaWrapper->nCols;
-      }
-
-      int32_t i = 0;
-      int32_t j = 0;
-      while (i < pSchemaWrapper->nCols && j < numOfCols) {
-        SSchema* pColSchema = &pSchemaWrapper->pSchema[i];
-        col_id_t colIdSchema = pColSchema->colId;
-
-        col_id_t colIdNeed = *(col_id_t*)taosArrayGet(pReader->pColIdList, j);
-        if (colIdSchema < colIdNeed) {
-          i++;
-        } else if (colIdSchema > colIdNeed) {
-          j++;
-        } else {
-          SColumnInfoData colInfo = createColumnInfoData(pColSchema->type, pColSchema->bytes, pColSchema->colId);
-          int32_t         code = blockDataAppendColInfo(pBlock, &colInfo);
-          if (code != TSDB_CODE_SUCCESS) {
-            return -1;
-          }
-          i++;
-          j++;
-        }
+    if (blockDataGetNumOfCols(pBlock) == 0) {
+      int32_t code = buildResSDataBlock(pReader->pResBlock, pReader->pSchemaWrapper, pReader->pColIdList);
+      if (code != TSDB_CODE_SUCCESS) {
+        return code;
       }
     }
   }