feat: add multi-rows merge join

source/libs/executor/src/joinoperator.c

@@ -146,6 +146,39 @@ static void mergeJoinJoinLeftRight(struct SOperatorInfo* pOperator, SSDataBlock*
   }
 
 }
+typedef struct SRowLocation {
+    SSDataBlock* pDataBlock;
+    int32_t pos;
+} SRowLocation;
+
+static int32_t mergeJoinGetBlockRowsEqualStart(SSDataBlock* pBlock, int16_t slotId, int32_t startPos,
+                                                   SArray* pPosArray) {
+  int32_t numRows = pBlock->info.rows;
+  ASSERT(startPos < numRows);
+  SColumnInfoData* pCol = taosArrayGet(pBlock->pDataBlock, slotId);
+
+  int32_t i = startPos;
+  char*   pVal = colDataGetData(pCol, i);
+  for (i = startPos + 1; i < numRows; ++i) {
+    char* pNextVal = colDataGetData(pCol, i);
+    if (*(int64_t*)pVal != *(int64_t*)pNextVal) {
+      break;
+    }
+  }
+  int32_t endPos = i;
+
+  SSDataBlock* block = pBlock;
+  if (endPos - startPos > 1) {
+    block = blockDataExtractBlock(pBlock, startPos, endPos - startPos);
+  }
+  SRowLocation  location = {0};
+  for (int32_t j = startPos; j < endPos; ++j) {
+    location.pDataBlock = block;
+    location.pos = j;
+    taosArrayPush(pPosArray, &location);
+  }
+  return 0;
+}
 
 static bool mergeJoinGetNextTimestamp(SOperatorInfo* pOperator, int64_t* pLeftTs, int64_t* pRightTs) {
   SJoinOperatorInfo* pJoinInfo = pOperator->info;