bindinfo: add last_used_date to track bindinfo usage frequency (#63409)

[ti-chi-bot]

This is an automated cherry-pick of #63409
cherry-pick of #60296

What problem does this PR solve?

Issue Number: close #63407

Problem Summary:

What changed and how does it work?

Currently, some customers have created a large number of bindings. However, it is difficult to determine whether these bindings are still in use. The sheer volume of bindings also puts pressure on TiDB. Therefore, we need a way to identify and mark the bindings that are not in use.

Check List

Tests

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

start a tidb with master which is started by script. Tikv and PD is started by tiup playground nightly --mode tikv-slim.

+----------------------------------+----------------------------------+------------+---------+-------------------------+-------------------------+---------+-----------+---------+------------+-------------+
| original_sql                     | bind_sql                         | default_db | status  | create_time             | update_time             | charset | collation | source  | sql_digest | plan_digest |
+----------------------------------+----------------------------------+------------+---------+-------------------------+-------------------------+---------+-----------+---------+------------+-------------+
| builtin_pseudo_sql_for_bind_lock | builtin_pseudo_sql_for_bind_lock | mysql      | builtin | 0000-00-00 00:00:00.000 | 0000-00-00 00:00:00.000 |         |           | builtin | <null>     | <null>      |
+----------------------------------+----------------------------------+------------+---------+-------------------------+-------------------------+---------+-----------+---------+------------+-------------+

kill this TiDB and start changed tidb verson.

+----------------------------------+----------------------------------+------------+---------+-------------------------+-------------------------+---------+-----------+---------+------------+-------------+----------------+
| original_sql                     | bind_sql                         | default_db | status  | create_time             | update_time             | charset | collation | source  | sql_digest | plan_digest | last_used_time |
+----------------------------------+----------------------------------+------------+---------+-------------------------+-------------------------+---------+-----------+---------+------------+-------------+----------------+
| builtin_pseudo_sql_for_bind_lock | builtin_pseudo_sql_for_bind_lock | mysql      | builtin | 0000-00-00 00:00:00.000 | 0000-00-00 00:00:00.000 |         |           | builtin | <null>     | <null>      | <null>         |
+----------------------------------+----------------------------------+------------+---------+-------------------------+-------------------------+---------+-----------+---------+------------+-------------+----------------+

BTW

The code in this area still differs from that on the master branch, which may lead to performance issues. The difference lies in the fact that version 8.5 requires an additional memory setting operation. However, from what we can see on the profiler

According to the flame graph, this part only accounts for 0.1% of the total query cost. Therefore, one additional set operation is roughly equivalent to the cost of one get operation, making the overall impact very limited.

I add a benchmark for binding. The overhead here is less than 3%. The overhead of TiKV has not been taken into account here. This part only ran the EXPLAIN command and did not execute the query.

before

BenchmarkFuzzyBindingBasic-8   	    1143	    903480 ns/op	 1178957 B/op	   15274 allocs/op

after

BenchmarkFuzzyBindingBasic-8   	    1318	    932915 ns/op	 1189334 B/op	   15624 allocs/op

• 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

[ti-chi-bot]

This cherry pick PR is for a release branch and has not yet been approved by triage owners.
Adding the do-not-merge/cherry-pick-not-approved label.

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[ti-chi-bot]

@hawkingrei This PR has conflicts, I have hold it.
Please resolve them or ask others to resolve them, then comment /unhold to remove the hold label.

[ti-chi-bot]

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[codecov]

Codecov Report

❌ Patch coverage is 78.32512% with 44 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (release-8.5@e9af1b4). Learn more about missing BASE report.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-8.5     #63824   +/-   ##
================================================
  Coverage               ?   77.2261%           
================================================
  Files                  ?       1654           
  Lines                  ?     455175           
  Branches               ?          0           
================================================
  Hits                   ?     351514           
  Misses                 ?      82186           
  Partials               ?      21475           

Flag	Coverage Δ
integration	50.4380% <54.6798%> (?)
unit	72.7512% <71.9211%> (?)

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

Components	Coverage Δ
dumpling	52.9278% <0.0000%> (?)
parser	∅ <0.0000%> (?)
br	63.3626% <0.0000%> (?)

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[hawkingrei]

/retest

[hawkingrei]

/retest

[hawkingrei]

/retest

[hawkingrei]

/unhold

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-10-15 08:34:53.599137199 +0000 UTC m=+255999.676389759: ☑️ agreed by qw4990.
• 2025-10-21 02:41:08.780548785 +0000 UTC m=+753174.857801345: ☑️ agreed by you06.

[D3Hunter]

/approve

[yudongusa]

Please open doc PR on this

[hawkingrei]

/retest

[hawkingrei]

Please open doc PR on this

Please create a doc PR here.

pingcap/docs#21948
pingcap/docs#21946

[BornChanger]

br side lgtm.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: BornChanger, D3Hunter, hawkingrei, Leavrth, qw4990, you06, yudongusa

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

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Needs approval from an approver in each of these files:

• OWNERS [BornChanger,D3Hunter,Leavrth,hawkingrei,qw4990,you06]
• br/OWNERS [BornChanger,Leavrth]
• pkg/bindinfo/OWNERS [hawkingrei,qw4990]
• pkg/domain/OWNERS [D3Hunter]
• pkg/infoschema/OWNERS [D3Hunter]
• pkg/session/OWNERS [yudongusa]
• pkg/sessionctx/variable/OWNERS [yudongusa]

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