[TD-10986]<feature>: Add elapsed function.

src/client/src/tscUtil.c

@@ -380,7 +380,7 @@ bool tscIsPointInterpQuery(SQueryInfo* pQueryInfo) {
 }
 
 bool tscNeedTableSeqScan(SQueryInfo* pQueryInfo) {
-  return tscQueryContainsFunction(pQueryInfo, TSDB_FUNC_TWA) || tscQueryContainsFunction(pQueryInfo, TSDB_FUNC_ELAPSED);
+  return pQueryInfo->stableQuery && (tscQueryContainsFunction(pQueryInfo, TSDB_FUNC_TWA) || tscQueryContainsFunction(pQueryInfo, TSDB_FUNC_ELAPSED));
 }
 
 bool tsIsArithmeticQueryOnAggResult(SQueryInfo* pQueryInfo) {

src/query/src/qAggMain.c

@@ -5090,15 +5090,45 @@ static void elapsedFunction(SQLFunctionCtx *pCtx) {
       pInfo->min = pCtx->preAggVals.statis.min;
       pInfo->max = pCtx->preAggVals.statis.max;
     } else {
+      if (pCtx->order == TSDB_ORDER_ASC) {
         pInfo->max = pCtx->preAggVals.statis.max;
+      } else {
+        pInfo->min = pCtx->preAggVals.statis.min;
+      }
     }
   } else {
+    // 0 == pCtx->size mean this is end interpolation.
     if (0 == pCtx->size) {
+      if (pCtx->order == TSDB_ORDER_DESC) {
+        if (pCtx->end.key != INT64_MIN) {
+          pInfo->min = pCtx->end.key;
+        }
+      } else {
+        if (pCtx->end.key != INT64_MIN) {
+          pInfo->max = pCtx->end.key + 1;
+        }
+      }
       goto elapsedOver;
     }
 
+    int64_t *ptsList = (int64_t *)GET_INPUT_DATA_LIST(pCtx);
+    // pCtx->start.key == INT64_MIN mean this is first window or there is actual start point of current window.
+    // pCtx->end.key == INT64_MIN mean current window does not end in current data block or there is actual end point of current window.
+    if (pCtx->order == TSDB_ORDER_DESC) {
       if (pCtx->start.key == INT64_MIN) {
-      pInfo->min = pCtx->ptsList[0];
+        pInfo->max = (pInfo->max < ptsList[pCtx->size - 1]) ? ptsList[pCtx->size - 1] : pInfo->max;
+      } else {
+        pInfo->max = pCtx->start.key + 1;
+      }
+
+      if (pCtx->end.key != INT64_MIN) {
+        pInfo->min = pCtx->end.key;
+      } else {
+        pInfo->min = ptsList[0];
+      }
+    } else {
+      if (pCtx->start.key == INT64_MIN) {
+        pInfo->min = (pInfo->min > ptsList[0]) ? ptsList[0] : pInfo->min;
       } else {
         pInfo->min = pCtx->start.key;
       }
@@ -5106,7 +5136,8 @@ static void elapsedFunction(SQLFunctionCtx *pCtx) {
       if (pCtx->end.key != INT64_MIN) {
         pInfo->max = pCtx->end.key + 1;
       } else {
-      pInfo->max = pCtx->ptsList[pCtx->size - 1];
+        pInfo->max = ptsList[pCtx->size - 1];
+      }
     }
   }
 

src/query/src/qExecutor.c

@@ -1531,7 +1531,6 @@ static void hashIntervalAgg(SOperatorInfo* pOperatorInfo, SResultRowInfo* pResul
 
   STimeWindow win = getActiveTimeWindow(pResultRowInfo, ts, pQueryAttr);
   bool masterScan = IS_MASTER_SCAN(pRuntimeEnv);
-
   SResultRow* pResult = NULL;
   int32_t ret = setResultOutputBufByKey(pRuntimeEnv, pResultRowInfo, pSDataBlock->info.tid, &win, masterScan, &pResult, tableGroupId, pInfo->pCtx,
                                         numOfOutput, pInfo->rowCellInfoOffset);
@@ -1564,11 +1563,10 @@ static void hashIntervalAgg(SOperatorInfo* pOperatorInfo, SResultRowInfo* pResul
       assert(!resultRowInterpolated(pResult, RESULT_ROW_END_INTERP));
 
       doTimeWindowInterpolation(pOperatorInfo, pInfo, pSDataBlock->pDataBlock, *(TSKEY*)pRuntimeEnv->prevRow[0], -1,
-                                  tsCols[startPos], startPos, w.ekey, RESULT_ROW_END_INTERP);
+                                tsCols[startPos], startPos, QUERY_IS_ASC_QUERY(pQueryAttr) ? w.ekey : w.skey, RESULT_ROW_END_INTERP);
 
       setResultRowInterpo(pResult, RESULT_ROW_END_INTERP);
       setNotInterpoWindowKey(pInfo->pCtx, pQueryAttr->numOfOutput, RESULT_ROW_START_INTERP);
-
       doApplyFunctions(pRuntimeEnv, pInfo->pCtx, &w, startPos, 0, tsCols, pSDataBlock->info.rows, numOfOutput);
     }