executor: some minor refine for hash join v2 build

[windtalker]

What problem does this PR solve?

Issue Number: ref #53127

Problem Summary:

What changed and how does it work?

1. During hash join v2 build, it will pre-allocate maxRowTableSegmentSize(which is 1024) rows for a new rowTableSegment
   

   tidb/pkg/executor/join/join_row_table.go

   Lines 87 to 95 in 634ac69

   	func newRowTableSegment() *rowTableSegment {
   	return &rowTableSegment{
   	// TODO: @XuHuaiyu if joinKeyIsInlined, the cap of rawData can be calculated
   	rawData: make([]byte, 0),
   	hashValues: make([]uint64, 0, maxRowTableSegmentSize),
   	rowStartOffset: make([]uint64, 0, maxRowTableSegmentSize),
   	validJoinKeyPos: make([]int, 0, maxRowTableSegmentSize),
   	}
   	}

   
   For small queries, it is a waste to pre allocate so many memories and may hurt the performance in high concurrency scenarios.
   In this pr, when constructing a new rowTableSegment, it will use chunk_row_number/partition_number * 1.2 as the row size hint for the first rowTableSegment, but still use maxRowTableSegmentSize as the row size hint for the following rowTableSegment.

2. Add maxRowTableSegmentByteSize to control the max memory size of a rowTableSegment.

3. Since rowTableSegment saves rowStartOffset directly, there is no need to save row offset in builder.startPosInRawData, so remove startPosInRawData in rowTableBuilder

4. rename crrntSizeOfRowTable to rowNumberInCurrentRowTableSeg

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• 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 @windtalker. Thanks for your PR.

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[xzhangxian1008]

/assign

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 55.6712%. Comparing base (634ac69) to head (8aa9eff).
Report is 57 commits behind head on master.

Additional details and impacted files

@@                Coverage Diff                @@
##             master     #54429         +/-   ##
=================================================
- Coverage   72.8354%   55.6712%   -17.1643%     
=================================================
  Files          1535       1657        +122     
  Lines        435896     608187     +172291     
=================================================
+ Hits         317487     338585      +21098     
- Misses        98795     246295     +147500     
- Partials      19614      23307       +3693     

Flag	Coverage Δ
integration	23.0628% <0.0000%> (?)
unit	71.8311% <100.0000%> (-0.0063%)	⬇️

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

Components	Coverage Δ
dumpling	52.9656% <ø> (ø)
parser	∅ <ø> (∅)
br	52.6890% <ø> (+6.6246%)	⬆️

[xzhangxian1008]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: XuHuaiyu, xzhangxian1008

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-07-05 03:03:10.663133375 +0000 UTC m=+1552717.148622205: ☑️ agreed by xzhangxian1008.
• 2024-07-08 06:37:39.268194276 +0000 UTC m=+253156.503428389: ☑️ agreed by XuHuaiyu.

[hawkingrei]

/retest

[ti-chi-bot]

@windtalker: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
idc-jenkins-ci-tidb/check_dev	8aa9eff	link	true	/test check-dev

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