fix: delete by expr failed at retry progress (milvus-io#35241)

issue: milvus-io#35240
delete by expr shard the same err object between channels, so if one
channel's query failed, it will fail all channel, which will break
channel level retry policy, and make delete operation failed.

Signed-off-by: Wei Liu <[email protected]>

internal/proxy/task_delete.go

@@ -247,7 +247,6 @@ type deleteRunner struct {
 	ts    uint64
 	lb    LBPolicy
 	count atomic.Int64
-	err   error
 
 	// task queue
 	queue *dmTaskQueue
@@ -430,7 +429,11 @@ func (dr *deleteRunner) getStreamingQueryAndDelteFunc(plan *planpb.PlanNode) exe
 		}
 
 		taskCh := make(chan *deleteTask, 256)
-		go dr.receiveQueryResult(ctx, client, taskCh)
+		var receiveErr error
+		go func() {
+			receiveErr = dr.receiveQueryResult(ctx, client, taskCh)
+			close(taskCh)
+		}()
 		// wait all task finish
 		for task := range taskCh {
 			err := task.WaitToFinish()
@@ -441,50 +444,42 @@ func (dr *deleteRunner) getStreamingQueryAndDelteFunc(plan *planpb.PlanNode) exe
 		}
 
 		// query or produce task failed
-		if dr.err != nil {
-			return dr.err
+		if receiveErr != nil {
+			return receiveErr
 		}
 		return nil
 	}
 }
 
-func (dr *deleteRunner) receiveQueryResult(ctx context.Context, client querypb.QueryNode_QueryStreamClient, taskCh chan *deleteTask) {
-	defer func() {
-		close(taskCh)
-	}()
-
+func (dr *deleteRunner) receiveQueryResult(ctx context.Context, client querypb.QueryNode_QueryStreamClient, taskCh chan *deleteTask) error {
 	for {
 		result, err := client.Recv()
 		if err != nil {
 			if err == io.EOF {
 				log.Debug("query stream for delete finished", zap.Int64("msgID", dr.msgID))
-				return
+				return nil
 			}
-			dr.err = err
-			return
+			return err
 		}
 
 		err = merr.Error(result.GetStatus())
 		if err != nil {
-			dr.err = err
 			log.Warn("query stream for delete get error status", zap.Int64("msgID", dr.msgID), zap.Error(err))
-			return
+			return err
 		}
 
 		if dr.limiter != nil {
 			err := dr.limiter.Alloc(ctx, []int64{dr.collectionID}, internalpb.RateType_DMLDelete, proto.Size(result.GetIds()))
 			if err != nil {
-				dr.err = err
 				log.Warn("query stream for delete failed because rate limiter", zap.Int64("msgID", dr.msgID), zap.Error(err))
-				return
+				return err
 			}
 		}
 
 		task, err := dr.produce(ctx, result.GetIds())
 		if err != nil {
-			dr.err = err
 			log.Warn("produce delete task failed", zap.Error(err))
-			return
+			return err
 		}
 
 		taskCh <- task