topsql: fix memory leak in stmtstats

[mornyx]

Signed-off-by: mornyx [email protected]

What problem does this PR solve?

Issue Number: ref #34525, #34502

In #33861, we also call the stmtstats framework to record the execution of statements when TopSQL is not enabled, but the aggregator inside stmtstats will take data only when TopSQL is enabled. So the memory leak happens.

In this PR, the behavior becomes: even if TopSQL is not enabled, the aggregator in stmtstats will take the data, but just discard it, not send it to the reporter.

Release note

None

[ti-chi-bot]

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• crazycs520
• zhongzc

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[mornyx]

/cc @zhongzc @crazycs520 PTAL, thanks!

[breezewish]

How about tests to avoid regression?

[mornyx]

How about tests to avoid regression?

It was my fault in code review, I updated the unit tests but only covered this PR scenario. It is difficult to expose all possible memory leaks through unit or integration tests, which require long runs..

But I think mistakes like "missing some changes" can be avoided with more careful reviews, rather than being exposed until the QA stage.

[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/3beef075a8e6a0cc35047171956c3fd61da3280f

[mornyx]

/assign @crazycs520

Please merge, thanks

[crazycs520]

/merge

[ti-chi-bot]

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

Commit hash: be524ec

[sre-bot]

TiDB MergeCI notify

CI Name	Result	Duration	Compare with Parent commit
idc-jenkins-ci/integration-cdc-test	🟢 all 34 tests passed	27 min	Existing passed
idc-jenkins-ci-tidb/integration-common-test	🟢 all 11 tests passed	11 min	Existing passed
idc-jenkins-ci-tidb/tics-test	🟢 all 1 tests passed	8 min 43 sec	Existing passed
idc-jenkins-ci-tidb/common-test	🟢 all 12 tests passed	7 min 7 sec	Existing passed
idc-jenkins-ci-tidb/integration-ddl-test	🟢 all 6 tests passed	6 min 34 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-1	🟢 all 26 tests passed	6 min 17 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-2	🟢 all 28 tests passed	5 min 58 sec	Existing passed
idc-jenkins-ci-tidb/mybatis-test	🟢 all 1 tests passed	3 min 34 sec	Existing passed
idc-jenkins-ci-tidb/integration-compatibility-test	🟢 all 1 tests passed	3 min 17 sec	Existing passed
idc-jenkins-ci-tidb/plugin-test	🟢 build success, plugin test success	4min	Existing passed