more work

source/dnode/vnode/src/inc/tsdb.h

@@ -151,6 +151,7 @@ int32_t tBlockDataAddColData(SBlockData *pBlockData, int32_t iColData, SColData
 int32_t tBlockDataAppendRow(SBlockData *pBlockData, TSDBROW *pRow, STSchema *pTSchema);
 int32_t tBlockDataMerge(SBlockData *pBlockData1, SBlockData *pBlockData2, SBlockData *pBlockData);
 int32_t tBlockDataCopy(SBlockData *pBlockDataSrc, SBlockData *pBlockDataDest);
+void    tBlockDataGetColData(SBlockData *pBlockData, int16_t cid, SColData **ppColData);
 // SDelIdx
 int32_t tPutDelIdx(uint8_t *p, void *ph);
 int32_t tGetDelIdx(uint8_t *p, void *ph);

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

@@ -1331,3 +1331,16 @@ int32_t tBlockDataCopy(SBlockData *pBlockDataSrc, SBlockData *pBlockDataDest) {
 _exit:
   return code;
 }
+
+void tBlockDataGetColData(SBlockData *pBlockData, int16_t cid, SColData **ppColData) {
+  ASSERT(cid != PRIMARYKEY_TIMESTAMP_COL_ID);
+
+  SColData *pColData = &(SColData){.cid = cid};
+
+  void *p = taosArraySearch(pBlockData->aColDataP, &pColData, tColDataPCmprFn, TD_EQ);
+  if (p == NULL) {
+    *ppColData = NULL;
+  } else {
+    *ppColData = *(SColData **)p;
+  }
+}
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