maintainer,dispatcher: dedupe waiting dispatcherStatus #4841
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,194 @@ | ||
| // Copyright 2026 PingCAP, Inc. | ||
| // | ||
| // Licensed under the Apache License, Version 2.0 (the "License"); | ||
| // you may not use this file except in compliance with the License. | ||
| // You may obtain a copy of the License at | ||
| // | ||
| // http://www.apache.org/licenses/LICENSE-2.0 | ||
| // | ||
| // Unless required by applicable law or agreed to in writing, software | ||
| // distributed under the License is distributed on an "AS IS" BASIS, | ||
| // See the License for the specific language governing permissions and | ||
| // limitations under the License. | ||
|
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| package dispatcher | ||
|
|
||
| import ( | ||
| "context" | ||
| "sync" | ||
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|
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| "github.com/pingcap/ticdc/heartbeatpb" | ||
| "github.com/pingcap/ticdc/pkg/common" | ||
| ) | ||
|
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| type blockStatusKey struct { | ||
| dispatcherID common.DispatcherID | ||
| blockTs uint64 | ||
| mode int64 | ||
| isSyncPoint bool | ||
| } | ||
|
|
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| type blockStatusQueueEntry struct { | ||
| status *heartbeatpb.TableSpanBlockStatus | ||
| doneKey *blockStatusKey | ||
| } | ||
|
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| // BlockStatusBuffer keeps block statuses ordered while coalescing identical | ||
| // WAITING and DONE statuses that are still pending locally. Other statuses keep | ||
| // the original protobuf object and ordering. | ||
| type BlockStatusBuffer struct { | ||
| queue chan blockStatusQueueEntry | ||
|
|
||
| mu sync.Mutex | ||
| pendingDone map[blockStatusKey]struct{} | ||
| pendingWaiting map[blockStatusKey]struct{} | ||
| } | ||
|
|
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| // NewBlockStatusBuffer creates a bounded local mailbox for dispatcher block | ||
| // statuses. The buffer keeps enqueue order while coalescing identical pending | ||
| // WAITING and DONE statuses before protobuf materialization. | ||
| func NewBlockStatusBuffer(size int) *BlockStatusBuffer { | ||
| if size <= 0 { | ||
| size = 1 | ||
| } | ||
| return &BlockStatusBuffer{ | ||
| queue: make(chan blockStatusQueueEntry, size), | ||
| pendingDone: make(map[blockStatusKey]struct{}), | ||
| pendingWaiting: make(map[blockStatusKey]struct{}), | ||
| } | ||
| } | ||
|
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| func (b *BlockStatusBuffer) Offer(status *heartbeatpb.TableSpanBlockStatus) { | ||
| if status == nil { | ||
| return | ||
| } | ||
| if isWaitingBlockStatus(status) { | ||
| key := newBlockStatusKey(status) | ||
| if !b.reserveWaiting(key) { | ||
| return | ||
| } | ||
| b.queue <- blockStatusQueueEntry{status: status} | ||
| return | ||
| } | ||
| if !isDoneBlockStatus(status) { | ||
| b.queue <- blockStatusQueueEntry{status: status} | ||
| return | ||
| } | ||
|
|
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| key := newBlockStatusKey(status) | ||
| if !b.reserveDone(key) { | ||
| return | ||
| } | ||
| b.queue <- blockStatusQueueEntry{doneKey: &key} | ||
| } | ||
|
|
||
| func (b *BlockStatusBuffer) OfferDone( | ||
| dispatcherID common.DispatcherID, | ||
| blockTs uint64, | ||
| isSyncPoint bool, | ||
| mode int64, | ||
| ) { | ||
| key := blockStatusKey{ | ||
| dispatcherID: dispatcherID, | ||
| blockTs: blockTs, | ||
| mode: mode, | ||
| isSyncPoint: isSyncPoint, | ||
| } | ||
| if !b.reserveDone(key) { | ||
| return | ||
| } | ||
| b.queue <- blockStatusQueueEntry{doneKey: &key} | ||
| } | ||
|
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| func (b *BlockStatusBuffer) Take(ctx context.Context) *heartbeatpb.TableSpanBlockStatus { | ||
| select { | ||
| case <-ctx.Done(): | ||
| return nil | ||
| case entry := <-b.queue: | ||
| return b.materialize(entry) | ||
| } | ||
| } | ||
|
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| func (b *BlockStatusBuffer) TryTake() (*heartbeatpb.TableSpanBlockStatus, bool) { | ||
| select { | ||
| case entry := <-b.queue: | ||
| return b.materialize(entry), true | ||
| default: | ||
| return nil, false | ||
| } | ||
| } | ||
|
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| func (b *BlockStatusBuffer) Len() int { | ||
| return len(b.queue) | ||
| } | ||
|
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| func (b *BlockStatusBuffer) reserveWaiting(key blockStatusKey) bool { | ||
| b.mu.Lock() | ||
| defer b.mu.Unlock() | ||
| if _, ok := b.pendingWaiting[key]; ok { | ||
| return false | ||
| } | ||
| b.pendingWaiting[key] = struct{}{} | ||
| return true | ||
| } | ||
|
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| func (b *BlockStatusBuffer) reserveDone(key blockStatusKey) bool { | ||
| b.mu.Lock() | ||
| defer b.mu.Unlock() | ||
| if _, ok := b.pendingDone[key]; ok { | ||
| return false | ||
| } | ||
| b.pendingDone[key] = struct{}{} | ||
| return true | ||
| } | ||
|
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| func (b *BlockStatusBuffer) materialize(entry blockStatusQueueEntry) *heartbeatpb.TableSpanBlockStatus { | ||
| if entry.status != nil { | ||
| if isWaitingBlockStatus(entry.status) { | ||
| key := newBlockStatusKey(entry.status) | ||
| b.mu.Lock() | ||
| delete(b.pendingWaiting, key) | ||
| b.mu.Unlock() | ||
| } | ||
| return entry.status | ||
| } | ||
|
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| key := *entry.doneKey | ||
| b.mu.Lock() | ||
| delete(b.pendingDone, key) | ||
| b.mu.Unlock() | ||
|
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| return &heartbeatpb.TableSpanBlockStatus{ | ||
| ID: key.dispatcherID.ToPB(), | ||
| State: &heartbeatpb.State{ | ||
| IsBlocked: true, | ||
| BlockTs: key.blockTs, | ||
| IsSyncPoint: key.isSyncPoint, | ||
| Stage: heartbeatpb.BlockStage_DONE, | ||
| }, | ||
| Mode: key.mode, | ||
| } | ||
| } | ||
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| func newBlockStatusKey(status *heartbeatpb.TableSpanBlockStatus) blockStatusKey { | ||
| return blockStatusKey{ | ||
| dispatcherID: common.NewDispatcherIDFromPB(status.ID), | ||
| blockTs: status.State.BlockTs, | ||
| mode: status.Mode, | ||
| isSyncPoint: status.State.IsSyncPoint, | ||
| } | ||
| } | ||
|
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| func isWaitingBlockStatus(status *heartbeatpb.TableSpanBlockStatus) bool { | ||
| return status != nil && | ||
| status.State != nil && | ||
| status.State.IsBlocked && | ||
| status.State.Stage == heartbeatpb.BlockStage_WAITING | ||
| } | ||
|
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| func isDoneBlockStatus(status *heartbeatpb.TableSpanBlockStatus) bool { | ||
| return status != nil && | ||
| status.State != nil && | ||
| status.State.IsBlocked && | ||
| status.State.Stage == heartbeatpb.BlockStage_DONE | ||
| } | ||
|
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Minor:
Offer()'s DONE path silently drops all State fields except key components.When
Offer()receives a DONE-staged status (Line 78-82), only the key (dispatcherID,blockTs,mode,isSyncPoint) is preserved via thedoneKeyplaceholder;materialize()(Line 161-170) then reconstructs a minimalTableSpanBlockStatusthat loses any additionalStatefields (BlockTables,NeedDroppedTables,NeedAddedTables,UpdatedSchemas) the caller may have populated.In the current PR this path is unreachable — all DONE messages flow through
OfferDoneBlockStatus/OfferDonewhich by design only carry the key fields — so behavior is preserved. However, the publicOffersignature accepts any*TableSpanBlockStatus, so a future caller that hands a DONE-staged status with extras intoOfferwould experience silent field loss.Consider one of:
Offerreceives a DONE-staged status with non-zero auxiliary fields.statuspointer for DONE too (skip the placeholder optimization for theOfferentry point) and only use the placeholder form fromOfferDone.Offerexplicitly stating that DONE statuses are reconstructed from key-only and must not carry extras.Also applies to: 145-171