store/tikv: resolve all locks no matter they're expired or not in BatchResolveLocks
#12784
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tiancaiamao
added
require-LGT3
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PTAL @coocood @MyonKeminta @jackysp |
Codecov Report
@@ Coverage Diff @@
## master #12784 +/- ##
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Coverage 79.9755% 79.9755%
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Files 465 465
Lines 107294 107294
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Hits 85809 85809
Misses 15000 15000
Partials 6485 6485 |
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Is there any test for it? |
MyonKeminta
reviewed
Oct 21, 2019
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LGTM |
Construct a counterexample that does unsafe GC in the unit test is not easy work. @MyonKeminta |
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@tiancaiamao How about try to test only the |
Sounds reasonable ... |
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PTAL @MyonKeminta |
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Ping @MyonKeminta |
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PTAL @MyonKeminta |
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/rebuild |
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PTAL @jackysp |
jackysp
added
the
status/can-merge
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Your auto merge job has been accepted, waiting for 12878 |
jackysp
added
status/LGT3
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/run-all-tests |
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What problem does this PR solve?
Should GC rollback a transaction even its lock TTL is not expired? That's hard to answer.
If we choose YES, transactions may be killed unexpectedly by GC.
If we choose NO, then the GC processing would be blocked by active transactions.
We're in a dilemma.
After we introduce the support for large transactions, the TTL may be updating.
It's hard to guarantee when GC could run if we let active transactions block GC.
The simpler solution is to let GC rollback transactions, which is the same as the elder version TiDB does.
What is changed and how it works?
In #11999 we choose to not resolve large transaction's lock, that's not a thoughtful change, and has potential correctness issues.
In this commit, BatchResolveLocks would resolve all locks no matter they're expired or not.
Check List
Tests