kv: reduce gRPC window size to avoid OOM (#2699)

[ti-chi-bot]

This is an automated cherry-pick of #2699

What problem does this PR solve?

Note: TiCDC in the following tests includes https://github.com/pingcap/ticdc/pull/2214.

Memory usage (pause sorter)

Tested with following changes

diff --git a/cdc/puller/sorter/unified_sorter.go b/cdc/puller/sorter/unified_sorter.go
index 9cd9c898..6e033429 100644
--- a/cdc/puller/sorter/unified_sorter.go
+++ b/cdc/puller/sorter/unified_sorter.go
@@ -197,9 +197,9 @@ func (s *UnifiedSorter) Run(ctx context.Context) error {
                }
        })
 
-       errg.Go(func() error {
-               return printError(runMerger(subctx, numConcurrentHeaps, heapSorterCollectCh, s.outputCh, ioCancelFunc))
-       })
+       // errg.Go(func() error {
+       //      return printError(runMerger(subctx, numConcurrentHeaps, heapSorterCollectCh, s.outputCh, ioCancelFunc))
+       // })
 
        errg.Go(func() error {
                captureAddr := util.CaptureAddrFromCtx(ctx)

64MB vs 64KB

The last image shows TiKV snapshot is holded for a long time, because CDC scan is flow controlled. Through, I doubt if it will actually happen as TiCDC sorter can always make progress.

Performance

No significant difference.

64MB (OOM) vs 64KB

Close #2673

What is changed and how it works?

Check List

Tests

• Manual test (add detailed scripts or steps below)

Related changes

• Need to cherry-pick to the release branch

Release note

Fix OOM when TiCDC captures too many regions

[ti-chi-bot]

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[amyangfei]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 045b8f0

[ti-chi-bot]

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[overvenus]

/run-unit-tests