executor: remove `EnablePointGetCache` session var

[YangKeao]

What problem does this PR solve?

Issue Number: close #55696

Problem Summary:

These codes are not modified for a very long time, and there is no option to enable this session var. Therefore, I think maybe it's safe to remove it :thinking:.

What changed and how does it work?

Simply remove the codes related to EnablePointGetCache.

Check List

Tests

• [ ] Unit test
• [ ] Integration test
• [ ] Manual test (add detailed scripts or steps below)
• [x] No need to test

  • [ ] I checked and no code files have been changed. This PR doesn't change the existing logic. The existing tests about normal point get should cover it.

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

[YangKeao]

I found a similar PR https://github.com/pingcap/tidb/pull/48962 :facepalm:. @Defined2014 Why do you close it?

[codecov[bot]]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 74.7898%. Comparing base (3d42e34) to head (9eddc89). :warning: Report is 2478 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #55697        +/-   ##
================================================
+ Coverage   72.9203%   74.7898%   +1.8695%     
================================================
  Files          1581       1582         +1     
  Lines        442365     442632       +267     
================================================
+ Hits         322574     331044      +8470     
+ Misses        99982      91292      -8690     
- Partials      19809      20296       +487     

Flag	Coverage Δ
integration	49.1201% <ø> (?)
unit	72.5499% <ø> (-0.1308%)	:arrow_down:

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

Components	Coverage Δ
dumpling	∅ <ø> (∅)
parser	∅ <ø> (∅)
br	52.6957% <ø> (+6.3749%)	:arrow_up:

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[Defined2014]

I found a similar PR #48962 🤦. @Defined2014 Why do you close it?

The session variable is removed by an accident. And we try to add back it before https://github.com/pingcap/tidb/pull/51008 But this was rejected, I think it's good to remove it. If I remember correctly, this feature was designed for POC and was never mentioned in the documentation.

[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Defined2014, lance6716 Once this PR has been reviewed and has the lgtm label, please assign easonn7 for approval. For more information see the Code Review Process.

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

Needs approval from an approver in each of these files:

• ~~OWNERS~~ [Defined2014,lance6716]
• pkg/sessionctx/variable/OWNERS

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[bot]]

[LGTM Timeline notifier]

Timeline:

• 2024-08-27 09:58:16.149650358 +0000 UTC m=+864291.284100488: :ballot_box_with_check: agreed by Defined2014.
• 2024-08-27 14:03:58.630706369 +0000 UTC m=+879033.765156489: :ballot_box_with_check: agreed by lance6716.

[lance6716]

/assign @yudongusa

[ti-chi-bot[bot]]

@lance6716: GitHub didn't allow me to assign the following users: yudongusa.

Note that only pingcap members with read permissions, repo collaborators and people who have commented on this issue/PR can be assigned. Additionally, issues/PRs can only have 10 assignees at the same time. For more information please see the contributor guide

In response to this:

/assign @yudongusa

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[ti-chi-bot[bot]]

PR needs rebase.

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[ti-chi-bot[bot]]

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

Test name	Commit	Details	Required	Rerun command
pull-integration-e2e-test	9eddc896a55938322bd5c832fdcc8fbe8d43386d	link	true	/test pull-integration-e2e-test
pull-integration-realcluster-test-next-gen	9eddc896a55938322bd5c832fdcc8fbe8d43386d	link	true	/test pull-integration-realcluster-test-next-gen
pull-unit-test-next-gen	9eddc896a55938322bd5c832fdcc8fbe8d43386d	link	true	/test pull-unit-test-next-gen

Full PR test history. Your PR dashboard.

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