Method executeTask

pkg/executor/distsql.go:1861–1973

executeTask executes the table look up tasks. We will construct a table reader and send request by handles. Then we hold the returning rows and finish this task.

(ctx context.Context, task *lookupTableTask)

// executeTask executes the table look up tasks. We will construct a table reader and send request by handles.
// Then we hold the returning rows and finish this task.
func (w *tableWorker) executeTask(ctx context.Context, task *lookupTableTask) error {
	tableReader, err := w.idxLookup.buildTableReader(ctx, task)
	task.buildDoneTime = time.Now()
	if err != nil {
		if ctx.Err() != context.Canceled {
			logutil.Logger(ctx).Error("build table reader failed", zap.Error(err))
		}
		return err
	}
	defer func() { terror.Log(exec.Close(tableReader)) }()

	if w.checkIndexValue != nil {
		return w.compareData(ctx, task, tableReader)
	}

	{
		task.memTracker = w.memTracker
		memUsage := int64(cap(task.handles))*size.SizeOfInterface + tableReader.memUsage()
		for _, h := range task.handles {
			memUsage += int64(h.MemUsage())
		}
		if task.indexOrder != nil {
			memUsage += task.indexOrder.MemUsage()
		}
		if task.duplicatedIndexOrder != nil {
			memUsage += task.duplicatedIndexOrder.MemUsage()
		}
		memUsage += task.idxRows.MemoryUsage()
		task.memUsage = memUsage
		task.memTracker.Consume(memUsage)
	}
	handleCnt := len(task.handles)
	task.rows = make([]chunk.Row, 0, handleCnt)
	for {
		chk := exec.TryNewCacheChunk(tableReader)
		err = exec.Next(ctx, tableReader, chk)
		if err != nil {
			if ctx.Err() != context.Canceled {
				logutil.Logger(ctx).Warn("table reader fetch next chunk failed", zap.Error(err))
			}
			return err
		}
		if chk.NumRows() == 0 {
			break
		}
		{
			memUsage := chk.MemoryUsage()
			task.memUsage += memUsage
			task.memTracker.Consume(memUsage)
		}
		iter := chunk.NewIterator4Chunk(chk)
		for row := iter.Begin(); row != iter.End(); row = iter.Next() {
			task.rows = append(task.rows, row)
		}
	}

	defer trace.StartRegion(ctx, "IndexLookUpTableCompute").End()
	{