infoschema: fix issue of information schema cache miss cause by schema version gap #53445
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…a version gap Signed-off-by: crazycs520 <[email protected]>
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Skipping CI for Draft Pull Request. |
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Codecov ReportAll modified and coverable lines are covered by tests ✅
Additional details and impacted files@@ Coverage Diff @@
## master #53445 +/- ##
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+ Coverage 72.5441% 75.0142% +2.4700%
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Files 1505 1505
Lines 429846 432958 +3112
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+ Hits 311828 324780 +12952
+ Misses 98749 88376 -10373
- Partials 19269 19802 +533
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| versions = append(versions, ver) | ||
| } | ||
| sort.Slice(versions, func(i, j int) bool { return versions[i] < versions[j] }) | ||
| for _, ver := range versions { |
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Is removing one version enough?
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Because empty schema version rarely appears, I think it's okay to delete just one here.
…-schema-cahce-hole
Signed-off-by: crazycs520 <[email protected]>
Signed-off-by: crazycs520 <[email protected]>
Signed-off-by: crazycs520 <[email protected]>
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/retest-required |
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| h.emptySchemaVersions[version] = struct{}{} | ||
| if len(h.emptySchemaVersions) > cap(h.cache) { | ||
| // remove oldest version. |
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without statistics of how those version are accessed, remove oldest is no better than remove random version, and more complex
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For stale-read query workload, it will always need recent schema version, so remove the oldest version is better.
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[LGTM Timeline notifier]Timeline:
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Nice catch, I try to use methold, but this will need to introduce another TiKV RPC to get the schemaTS of the empty schema version. |
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/retest-required |
…a version gap (pingcap#53445) close pingcap#53428 Signed-off-by: crazycs520 <[email protected]>
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In response to a cherrypick label: new pull request created to branch |
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Signed-off-by: ti-chi-bot <[email protected]>
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This reverts commit 0771279.
…a version gap (pingcap#53445) close pingcap#53428
…a version gap (pingcap#53445) close pingcap#53428 Signed-off-by: crazycs520 <[email protected]>
This reverts commit 2653442.
…a version gap (pingcap#53445) close pingcap#53428 Signed-off-by: crazycs520 <[email protected]>
…a version gap (#53445) (#53562) * infoschema: fix issue of information schema cache miss cause by schema version gap (#53445) close #53428 Signed-off-by: crazycs520 <[email protected]>
…a version gap (pingcap#53445) (pingcap#53583) (pingcap#97) close pingcap#53428 Co-authored-by: Ti Chi Robot <[email protected]>
What problem does this PR solve?
Issue Number: close #53428
Problem Summary: fix issue of information schema cache miss cause by schema version gap
What changed and how does it work?
before this PR
When DDL has empty schema version, will cause cache miss, then stale-read query need to load snapshot schema from TiKV.
This PR
When DDL has empty schema version, this PR won't have schema cache miss, then won't cause many load snapshot schema operation.
Check List
Tests
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Documentation
Release note
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