store: implement non-block read when coprocessor meets the lock of a large transaction #11986
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…large transaction
tiancaiamao
added
sig/transaction
Codecov Report
@@ Coverage Diff @@
## master #11986 +/- ##
===============================================
+ Coverage 80.2295% 80.317% +0.0874%
===============================================
Files 472 472
Lines 114843 115135 +292
===============================================
+ Hits 92138 92473 +335
+ Misses 15466 15421 -45
- Partials 7239 7241 +2 |
|
PTAL @coocood @crazycs520 |
tiancaiamao
requested review from
coocood,
lysu and
MyonKeminta
and removed request for
crazycs520
coocood
reviewed
Oct 15, 2019
| @@ -367,6 +367,7 @@ type copIteratorWorker struct { | |||
| respChan chan<- *copResponse | |||
| finishCh <-chan struct{} | |||
| vars *kv.Variables | |||
| clientHelper | |||
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Is clientHelper going to be used in other places?
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I'm not sure, but I can export it when it's used.
coocood
reviewed
Oct 15, 2019
coocood
reviewed
Oct 16, 2019
lysu
reviewed
Oct 16, 2019
lysu
reviewed
Oct 16, 2019
|
/rebuild |
coocood
reviewed
Oct 17, 2019
jackysp
reviewed
Nov 15, 2019
| @@ -0,0 +1,101 @@ | |||
| // Copyright 2019-present, PingCAP, Inc. | |||
jackysp
reviewed
Nov 15, 2019
store/tikv/lock_resolver.go
Outdated
| @@ -277,23 +277,24 @@ func (lr *LockResolver) BatchResolveLocks(bo *Backoffer, locks []*Lock, loc Regi | |||
| // commit status. | |||
| // 3) Send `ResolveLock` cmd to the lock's region to resolve all locks belong to | |||
| // the same transaction. | |||
| func (lr *LockResolver) ResolveLocks(bo *Backoffer, callerStartTS uint64, locks []*Lock) (int64, error) { | |||
| func (lr *LockResolver) ResolveLocks(bo *Backoffer, callerStartTS uint64, locks []*Lock) (int64, []uint64, error) { | |||
There was a problem hiding this comment.
It is better to add some comments for the return values.
lysu
reviewed
Nov 15, 2019
| } | ||
| } else { | ||
| tikvLockResolverCountWithNotExpired.Inc() | ||
| // If the lock is valid, the txn may be a pessimistic transaction. | ||
| // Update the txn expire time. | ||
| msBeforeLockExpired := lr.store.GetOracle().UntilExpired(l.TxnID, status.ttl) | ||
| msBeforeTxnExpired.update(msBeforeLockExpired) | ||
| if callerStartTS > 0 { | ||
| pushed = append(pushed, l.TxnID) | ||
| } |
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do we have rolling upgrade problem here?
old TiDB B write some locks with lock.minCommitTS == 0, new TiDB A read same key with callerStartTS > 0...
so those lock append but not be pushed? @tiancaiamao @coocood
tidb/store/mockstore/mocktikv/mvcc_leveldb.go
Line 1074 in 8dc46b2
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Good catch, we should try to push the transaction even if minCommitTS == 0
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Addressed.
We don't push minCommitTS == 0 and this information is returned, ResolveLocks will not set the pushed result in this case (thus the caller has to wait).
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/run-all-tests |
1 similar comment
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/run-all-tests |
coocood
reviewed
Nov 19, 2019
|
|
||
| // ResolveLocks wraps the ResolveLocks function and store the resolved result. | ||
| func (ch *clientHelper) ResolveLocks(bo *Backoffer, callerStartTS uint64, locks []*Lock) (int64, error) { | ||
| msBeforeTxnExpired, resolvedLocks, err := ch.LockResolver.ResolveLocks(bo, callerStartTS, locks) |
coocood
reviewed
Nov 19, 2019
store/tikv/2pc.go
Outdated
| @@ -128,6 +127,9 @@ type twoPhaseCommitter struct { | |||
| regionTxnSize map[uint64]int | |||
| // Used by pessimistic transaction and large transaction. | |||
| ttlManager | |||
|
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| // Used in the test code. | |||
| zeroCommitTS bool | |||
coocood
reviewed
Nov 19, 2019
store/tikv/2pc.go
Outdated
| @@ -489,6 +491,14 @@ func (c *twoPhaseCommitter) buildPrewriteRequest(batch batchKeys, txnSize uint64 | |||
| isPessimisticLock[i] = true | |||
| } | |||
| } | |||
| var minCommitTS uint64 | |||
| if !c.zeroCommitTS { | |||
There was a problem hiding this comment.
Can we add a failpoint to set minCommitTS to 0?
use failpoint to cover test
|
/bench |
Benchmark Report
@@ Benchmark Diff @@
================================================================================
--- tidb: 7f02792c5babab607ee6a86ef3ff6c2d85651b72
+++ tidb: 72eef5bac723e5f27b91cc000f038783c9a21ff9
tikv: 18bf609e78f81360e804ce5ce4ebf7d1a625e3d2
pd: 08e0143e83a2c42955bdfcbed4862f0339b9befc
================================================================================
oltp_update_non_index:
* QPS: 4713.20 ± 0.04% (std=1.22) delta: -0.50% (p=0.025)
* Latency p50: 27.16 ± 0.02% (std=0.00) delta: 0.51%
* Latency p99: 43.79 ± 2.72% (std=0.88) delta: 6.54%
oltp_insert:
* QPS: 4720.41 ± 0.18% (std=5.82) delta: -0.22% (p=0.033)
* Latency p50: 27.11 ± 0.18% (std=0.03) delta: 0.21%
* Latency p99: 48.34 ± 0.00% (std=0.00) delta: 4.09%
oltp_read_write:
* QPS: 15388.86 ± 0.10% (std=11.29) delta: 0.59% (p=0.051)
* Latency p50: 166.66 ± 0.10% (std=0.12) delta: -0.63%
* Latency p99: 306.13 ± 2.72% (std=6.16) delta: -5.70%
oltp_update_index:
* QPS: 4234.61 ± 0.02% (std=0.50) delta: -0.12% (p=0.337)
* Latency p50: 30.23 ± 0.02% (std=0.00) delta: 0.12%
* Latency p99: 55.35 ± 4.44% (std=1.64) delta: 3.24%
oltp_point_select:
* QPS: 39807.85 ± 0.47% (std=161.74) delta: 0.20% (p=0.594)
* Latency p50: 3.21 ± 0.54% (std=0.01) delta: -0.16%
* Latency p99: 9.65 ± 0.88% (std=0.08) delta: -0.46%
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|
/merge |
sre-bot
added
the
status/can-merge
|
/run-all-tests |
|
@tiancaiamao merge failed. |
XiaTianliang
pushed a commit
to XiaTianliang/tidb
that referenced
this pull request
Dec 21, 2019
…large transaction (pingcap#11986)
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What problem does this PR solve?
The lock of the large transaction should not block reading.
When a reader meets a lock, it pushes forward the minCommitTS and reads the data of a previous version.
What is changed and how it works?
This commit implements the read operation through coprocessor.
ScanandReverseScanoperation, to be exact.A
resolvedLockis passed as parameter to skip the lock.The first time a read operation meets a lock, it will resolve lock. And then the second request will carry this information to skip the conflicting locks.
Read operation using PointGet (Get or BatchGet) is not included in this PR.
I'll add that later in another commit.
Check List
Tests
Depends on the new implementation of ResolveLock