tikv: collapse duplicate resolve locks in region requests #16838
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lysu
added
component/tikv
needs-cherry-pick-4.0
type/enhancement
lysu
requested review from
tiancaiamao,
alexc711,
cfzjywxk and
coocood
and removed request for
alexc711
Codecov Report
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/run-all-tests |
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/build |
coocood
reviewed
Apr 27, 2020
store/tikv/client_collapse.go
Outdated
| case tikvrpc.CmdResolveLock: | ||
| resolveLock := req.ResolveLock() | ||
| if len(resolveLock.Keys) > 0 { | ||
| // can not collapse resolveLite |
store/tikv/client_collapse.go
Outdated
| return | ||
| } | ||
| canCollapse = true | ||
| key := addr + "-" + strconv.FormatUint(resolveLock.StartVersion, 10) + "-" + strconv.FormatUint(resolveLock.CommitVersion, 10) |
There was a problem hiding this comment.
The key doesn't have the region id.
And can we remove the store address from the key?
There was a problem hiding this comment.
The start ts is already unique, we don't need to include commit version in the key.
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Please address comment, rest LGTM |
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/run-all-tests |
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LGTM @coocood |
coocood
reviewed
Apr 29, 2020
store/tikv/client_collapse.go
Outdated
| func (r reqCollapse) collapse(ctx context.Context, key string, sf *singleflight.Group, | ||
| addr string, req *tikvrpc.Request, timeout time.Duration) (resp *tikvrpc.Response, err error) { | ||
| rsC := sf.DoChan(key, func() (interface{}, error) { | ||
| return r.Client.SendRequest(context.Background(), addr, req, ReadTimeoutMedium) // set longer timeout than outer's. |
There was a problem hiding this comment.
Why set longer timeout than outer's?
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LGTM |
coocood
approved these changes
Apr 29, 2020
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/merge |
sre-bot
added
the
status/can-merge
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/run-all-tests |
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cherry pick to release-4.0 in PR #16925 |
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What problem does this PR solve?
Issue Number: close #xxx
Problem Summary:
When txn1, txn2 meet txn1's lock, and txn1 is large txn that modify many keys
both txn1, txn2 will try to resolve(after check txn status) the whole region even if txn1 meet lock at k1 and txn2 meet lock at k2.
we can deduplicate resolve requests that try to resolve the whole region.
What is changed and how it works?
Proposal: xxx
What's Changed:
At first glance, we should do it in LockResolver, but the question is it's hard to maintain backoff behavior at LockResolver level:
if we collapse multiple lock requests into one request at LockResolver level, working request maybe meet many error and backoff(e.g. regionMiss, notLeader, kvRpc...), we are hard to let those backoff info feedback to collapsed requests that waiting for working request.
so this PR chooses to do it in lower level ---- at TiClient that this level, we only need to take care context.Cancel and timeout.
How it Works:
collapse multi resolve request into one request using singleflight.
and chose
DoChanto impl request level timeout and context.CancelRelated changes
Check List
Tests
Side effects
Release note
collapse duplicate resolve locks in region requests
This change is