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planner: LRUPlanCache memory trace #38069

Merged
merged 43 commits into from
Oct 21, 2022
Merged

planner: LRUPlanCache memory trace #38069

merged 43 commits into from
Oct 21, 2022

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fzzf678
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@fzzf678 fzzf678 commented Sep 22, 2022 •
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What problem does this PR solve?

Issue Number: ref #37632

Problem Summary:
Count the memory usage of LRUPlanCache

What is changed and how it works?

Implement MemoryUsage() for

  • planCacheKey
  • PlanCacheValue
  • LRUPlanCache

Check List

Tests

  • Unit test
  • Integration test
  • Manual test (add detailed scripts or steps below)
  • No code

Side effects

  • Performance regression: Consumes more CPU
  • Performance regression: Consumes more Memory
  • Breaking backward compatibility

Documentation

  • Affects user behaviors
  • Contains syntax changes
  • Contains variable changes
  • Contains experimental features
  • Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

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ti-chi-bot commented Sep 22, 2022 •
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[REVIEW NOTIFICATION]

This pull request has been approved by:

  • Reminiscent
  • qw4990

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

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@ti-chi-bot ti-chi-bot added release-note-none Denotes a PR that doesn't merit a release note. size/M Denotes a PR that changes 30-99 lines, ignoring generated files. labels Sep 22, 2022
@fzzf678 fzzf678 mentioned this pull request Sep 22, 2022
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@fzzf678 fzzf678 marked this pull request as draft September 22, 2022 00:59
@ti-chi-bot ti-chi-bot added the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label Sep 22, 2022
@fzzf678 fzzf678 marked this pull request as ready for review September 28, 2022 09:09
@ti-chi-bot ti-chi-bot removed the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label Sep 28, 2022
qw4990
qw4990 reviewed Oct 8, 2022
View reviewed changes
planner/core/plan_cache_lru.go Outdated
const emptyLRUPlanCacheSize = int64(unsafe.Sizeof(LRUPlanCache{}))

// MemoryUsage return the memory usage of LRUPlanCache
func (l *LRUPlanCache) MemoryUsage() (sum int64) {
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It seems like we should maintain its memory usage dynamically in l.Put.

@ti-chi-bot ti-chi-bot added size/L Denotes a PR that changes 100-499 lines, ignoring generated files. and removed size/M Denotes a PR that changes 30-99 lines, ignoring generated files. labels Oct 11, 2022
@ti-chi-bot ti-chi-bot added the status/LGT1 Indicates that a PR has LGTM 1. label Oct 19, 2022
qw4990
qw4990 reviewed Oct 20, 2022
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planner/core/plan_cache_utils.go Outdated
}

func (v *PlanCacheValue) varTypesUnchanged(txtVarTps []*types.FieldType) bool {
return v.ParamTypes.CheckTypesCompatibility4PC(txtVarTps)
}

// unKnownMemoryUsage represent the memory usage of uncounted structure, maybe need implement later
// 7 has no special meaning
const unKnownMemoryUsage = 7
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Seems too small. Actually, I have tested it before and got an empirical value 100KB, you can see it in our doc https://docs.pingcap.com/tidb/dev/sql-prepared-plan-cache#memory-management-of-prepared-plan-cache

qw4990
qw4990 reviewed Oct 20, 2022
View reviewed changes
planner/core/plan_cache_lru.go Outdated
// todo: pass label when track general plan cache memory
func newTrackerForLRUPC() *memory.Tracker {
m := memory.NewTracker(memory.LabelForPreparedPlanCache, -1)
m.Consume(emptyLRUPlanCacheSize)
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How about ignoring this part of memory usage?

qw4990
qw4990 reviewed Oct 20, 2022
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planner/core/plan_cache_lru.go Outdated
Comment on lines 252 to 259
func elementMemoryUsage(e *list.Element) (sum int64) {
pVal, ok1 := e.Value.(*planCacheEntry).PlanValue.(*PlanCacheValue)
pKey, ok2 := e.Value.(*planCacheEntry).PlanValue.(*planCacheKey)
if !ok1 || !ok2 {
return
}
return pKey.MemoryUsage() + pVal.MemoryUsage()
}
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Please implement this function as planCacheEntry.MemoryUsage

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fzzf678 commented Oct 20, 2022

/run-build

qw4990
qw4990 reviewed Oct 21, 2022
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planner/core/plan_cache_lru_test.go Outdated
v := &PlanCacheValue{Plan: p}
lru.Put(k, v, pTypes)
res += k.MemoryUsage() + v.MemoryUsage()
fmt.Println(lru.MemoryUsage(), res)
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Should remove this line.

@ti-chi-bot ti-chi-bot added size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. and removed size/L Denotes a PR that changes 100-499 lines, ignoring generated files. labels Oct 21, 2022
@ti-chi-bot ti-chi-bot added status/LGT2 Indicates that a PR has LGTM 2. and removed status/LGT1 Indicates that a PR has LGTM 1. labels Oct 21, 2022
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qw4990 commented Oct 21, 2022

/merge

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This pull request has been accepted and is ready to merge.

Commit hash: 0445583

@ti-chi-bot ti-chi-bot added the status/can-merge Indicates a PR has been approved by a committer. label Oct 21, 2022
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@fzzf678: Your PR was out of date, I have automatically updated it for you.

At the same time I will also trigger all tests for you:

/run-all-tests

If the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

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@ti-chi-bot ti-chi-bot merged commit f65f4ba into pingcap:master Oct 21, 2022
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@Reminiscent Reminiscent Reminiscent approved these changes

@qw4990 qw4990 qw4990 approved these changes

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