privilege: reuse chunk in loadTable function

[tiancaiamao]

What problem does this PR solve?

Issue Number: ref #55563

Problem Summary:

What changed and how does it work?

chunk.Renew cause more allocations and wastes memory, change the code from chunk.Renew to req.GrowAndReset(1024)

strings.Clone is required in decodeTableRow functions.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

Modify the code to call LoadSomeUsers manually, the database have 2M users and load 1/10 of them.

 func (e *ShowExec) fetchShowEngines(ctx context.Context) error {
+       fmt.Println("!!!!!!!")
        ctx = kv.WithInternalSourceType(ctx, kv.InternalTxnMeta)
-       exec := e.Ctx().GetRestrictedSQLExecutor()
+       // exec := e.Ctx().GetRestrictedSQLExecutor()
+
+       // rows, _, err := exec.ExecRestrictedSQL(ctx, nil, `SELECT * FROM information_schema.engines`)
+       // if err != nil {
+       //      return errors.Trace(err)
+       // }
+       // e.result.AppendRows(rows)
 
-       rows, _, err := exec.ExecRestrictedSQL(ctx, nil, `SELECT * FROM information_schema.engines`)
+       p := privileges.NewMySQLPrivilege()
+       userList := make(map[string]struct{}, 200000)
+       for i:=1000000; i< 1200000; i++ {
+               userList[fmt.Sprintf("test%d", i)] = struct{}{}
+       }
+       err := p.LoadSomeUsers(e.Ctx().GetSQLExecutor(), userList)
        if err != nil {
                return errors.Trace(err)
        }
 
-       e.result.AppendRows(rows)
        return nil
 }

Compare the memory usage before vs after:

And compare the heap alloc_space before vs after:

• No need to test

  • I checked and no code files have been changed.

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

[tiprow]

Hi @tiancaiamao. Thanks for your PR.

PRs from untrusted users cannot be marked as trusted with /ok-to-test in this repo meaning untrusted PR authors can never trigger tests themselves. Collaborators can still trigger tests on the PR using /test all.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.7946%. Comparing base (67edd7d) to head (20bbed4).
Report is 47 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #59821        +/-   ##
================================================
+ Coverage   72.9760%   73.7946%   +0.8186%     
================================================
  Files          1699       1703         +4     
  Lines        469387     476571      +7184     
================================================
+ Hits         342540     351684      +9144     
+ Misses       105739     103630      -2109     
- Partials      21108      21257       +149     

Flag	Coverage Δ
integration	42.9152% <100.0000%> (?)
unit	72.6364% <100.0000%> (+0.4582%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	52.6910% <ø> (ø)
parser	∅ <ø> (∅)
br	47.6816% <ø> (+2.6591%)	⬆️

🚀 New features to boost your workflow:

• ❄ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[tiancaiamao]

/retest

[tiprow]

@tiancaiamao: Cannot trigger testing until a trusted user reviews the PR and leaves an /ok-to-test message.

In response to this:

/retest

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: CbcWestwolf, lcwangchao

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [CbcWestwolf,lcwangchao]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-03-07 07:47:50.161679523 +0000 UTC m=+600583.290599271: ☑️ agreed by lcwangchao.
• 2025-03-10 05:43:32.143219991 +0000 UTC m=+161767.748748918: ☑️ agreed by CbcWestwolf.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.5: #59981.
But this PR has conflicts, please resolve them!