planner: fix time range extraction when time column is on the right side

[panmuyun]

What problem does this PR solve?

Issue Number: close #68770

Problem Summary:

extractTimeRange could not extract correct time bounds when the target time column appeared on the right side of a comparison predicate, such as '2019-10-10 10:10:10' < update_time. In that case, the extractor reused the original comparison operator without adjusting for operand order, so the lower or upper bound was missed or interpreted in the wrong direction.

This affects memtable predicate extraction paths that reuse extractTimeRange, including cluster_log, tidb_hot_regions_history, and metrics schema time filtering.

What changed and how does it work?

This PR fixes operand-order handling in extractTimeRange.

• Extend extractColBinaryOpConsExpr to return whether the extracted column is on the left side of the binary comparison.
• In extractTimeRange, when the target column is on the right side, normalize the comparison direction before updating the extracted time range:
  • < becomes >
  • <= becomes >=
  • > becomes <
  • >= becomes <=
• Keep the existing behavior unchanged for equality predicates and other helper callers that only need column/constant extraction.

This PR also adds regression tests for reversed time comparisons in existing extractor test cases:

• information_schema.cluster_log
• information_schema.tidb_hot_regions_history
• metrics_schema.tidb_query_duration

Check List

Tests

• Unit test

./tools/check/failpoint-go-test.sh pkg/planner/core/operator/logicalop/logicalop_test -run 'TestClusterLogTableExtractor|TestMetricTableExtractor|TestTiDBHotRegionsHistoryTableExtractor' -count=1

• 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

Summary by CodeRabbit

Bug Fixes

• Fixed time range filter handling for reversed comparison operators, ensuring both column > constant and constant < column forms produce correct results

Tests

• Added comprehensive test coverage for reversed time comparison patterns across multiple table types

[pantheon-ai]

@panmuyun I've received your pull request and will start the review. I'll conduct a thorough review covering code quality, potential issues, and implementation details.

⏳ This process typically takes 10-30 minutes depending on the complexity of the changes.

_{ℹ️ Learn more details on Pantheon AI.}

[ti-chi-bot]

Hi @panmuyun. Thanks for your PR.

I'm waiting for a pingcap member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Details

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.

[tiprow]

Hi @panmuyun. 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.

Details

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.

[coderabbitai]

📝 Walkthrough

Walkthrough

The PR fixes time range extraction for reversed predicates. extractColBinaryOpConsExpr now returns a boolean indicating whether the column appears left of the comparison operator. Time range extraction uses this to detect constant-left forms like '2019-10-10 10:10:10' < time_col, then inverts the operator before computing bounds, ensuring correct ranges for both normal and reversed forms.

Changes

Time range extraction with reversed predicate support

Layer / File(s)	Summary
Extraction function signature with column position flag pkg/planner/core/memtable_predicate_extractor.go	extractColBinaryOpConsExpr returns (colName, datums, colOnLeft) where colOnLeft indicates column position; all error/unsupported paths return ("", nil, false).
Call site adaptations for updated extraction signature pkg/planner/core/memtable_predicate_extractor.go	OR/EQ decomposition, main EQ case, and LIKE/REGEXP pattern extractors unpack the new 3-tuple return and discard the colOnLeft boolean while preserving existing pushdown and merge behavior.
Time range extraction with operator inversion for constant-left comparisons pkg/planner/core/memtable_predicate_extractor.go	Time range extraction captures colOnLeft; when true, the comparison operator is inverted (GT↔LT, GE↔LE) before applying existing start/end bound logic, enabling correct ranges for both time_col > const and const < time_col forms.
Test cases for reversed time comparisons pkg/planner/core/operator/logicalop/logicalop_test/logical_mem_table_predicate_extractor_test.go	Tests for cluster log, metric, and hot regions history table extractors added/updated to verify reversed comparisons like 'start' < time correctly extract time boundaries adjusted by ±1ms.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 When constants stand on the left with pride,
And time columns hide on the other side,
We flip the dance of less-than's grace,
Greater-than takes its swapped-around place.
Now bounds flow true for every case! 🕐✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main fix: handling time range extraction when the time column appears on the right side of a comparison.
Linked Issues check	✅ Passed	The PR successfully addresses issue #68770 by detecting right-side column placements and normalizing comparison operators before extracting time bounds.
Out of Scope Changes check	✅ Passed	All changes are directly related to fixing the time range extraction issue and adding corresponding test cases; no out-of-scope modifications detected.
Description check	✅ Passed	The PR description fully addresses the template requirements with clear issue reference, problem summary, detailed explanation of changes, test coverage documentation, and release note section.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-06-01 06:05:15.036174454 +0000 UTC m=+162416.106491864: ☑️ agreed by crazycs520.
• 2026-06-01 06:06:55.824042898 +0000 UTC m=+162516.894360278: ☑️ agreed by tangenta.

[codecov]

Codecov Report

❌ Patch coverage is 45.45455% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.2449%. Comparing base (99e1c67) to head (868a401).
⚠️ Report is 8 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #68826        +/-   ##
================================================
- Coverage   76.3104%   75.2449%   -1.0656%     
================================================
  Files          2041       2026        -15     
  Lines        563452     570622      +7170     
================================================
- Hits         429973     429364       -609     
- Misses       132563     140988      +8425     
+ Partials        916        270       -646     

Flag	Coverage Δ
integration	41.7851% <45.4545%> (+2.0066%)	⬆️

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

Components	Coverage Δ
dumpling	60.4610% <ø> (ø)
parser	∅ <ø> (∅)
br	49.8023% <ø> (-13.0287%)	⬇️

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[lance6716]

/ok-to-test

[lance6716]

/cc @AilinKid @winoros

[winoros]

My deleted comment is not suitable.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: crazycs520, tangenta, winoros

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

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• pkg/planner/OWNERS [winoros]

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

[panmuyun]

/retest

[panmuyun]

/retest

[ti-chi-bot]

@panmuyun: 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_2	868a401	link	unknown	/test check-dev2

Full PR test history. Your PR dashboard.

Details

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. I understand the commands that are listed here.