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table/tables: fix buildListColumnsPruner issue in the list partition #32621

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merged 4 commits into from
Mar 3, 2022

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@zimulala zimulala commented Feb 25, 2022

What problem does this PR solve?

Issue Number: close #32416

Problem Summary:
This also affects the master. This problem can also occur in the following scenario:

  1. Set the new collation configuration item to false and run the SQL statement above (create list partition table).
  2. Restart the TiDB and execute the select statement.
    The above scenario is analyzed in detail:

In step 1

In the bootstrap phase, new collation is true
After bootstrap ends, new collation is false.

In step 2

  1. In the bootstrap phase, new collation is true. ForListColumnPruning builds the hashMap(generate the partition hash key, by calling EncodeKey) in TableFromMeta
  2. After bootstrap ends, new collation is false. The generated partition hash key(by calling EncodeKey) could not be found in the hashMap.

What is changed and how it works?

Instead of creating the hashMap in the TableFromMeta phase( In the bootstrap phase), we create the hashMap on a delayed basis (that is, when a partition needs to be located).
In this way, new_collations_enabled_on_first_bootstrap does not have inconsistency problems.

Check List

Tests

  • Unit test
  • Integration test
  • Manual test (add detailed scripts or steps below)
  1. Set the new_collations_enabled_on_first_bootstrap item to false and run the SQL statements as follows:
set @@session.tidb_enable_list_partition = ON;
set @@tidb_partition_prune_mode = 'dynamic';
drop table if exists github_events;
CREATE TABLE `github_events` (
`id` bigint(20) DEFAULT NULL,
`type` varchar(255) COLLATE utf8mb4_unicode_ci DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
PARTITION BY LIST COLUMNS(`type`)
(PARTITION `push_event` VALUES IN ("PushEvent"),
PARTITION `watch_event` VALUES IN ("WatchEvent")
);
  1. Restart TiDB with new_collations_enabled_on_first_bootstrap = false and execute the following statements:
tidb> set @@session.tidb_enable_list_partition = ON;
Query OK, 0 rows affected (0.00 sec)

tidb> set @@tidb_partition_prune_mode = 'dynamic';
Query OK, 0 rows affected (0.00 sec)

tidb> desc select id,type from github_events  where  type = 'WatchEvent';
+-------------------------+----------+-----------+-----------------------+-------------------------------------------+
| id                      | estRows  | task      | access object         | operator info                             |
+-------------------------+----------+-----------+-----------------------+-------------------------------------------+
| TableReader_7           | 10.00    | root      | partition:watch_event | data:Selection_6                          |
| └─Selection_6           | 10.00    | cop[tikv] |                       | eq(test.github_events.type, "WatchEvent") |
|   └─TableFullScan_5     | 10000.00 | cop[tikv] | table:github_events   | keep order:false, stats:pseudo            |
+-------------------------+----------+-----------+-----------------------+-------------------------------------------+
3 rows in set (0.00 sec)

The above scenario is analyzed in detail:

  • No code

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

Fixed an issue where partition table pruning might not work after server restart (for list partition table)

@zimulala zimulala added type/bugfix This PR fixes a bug. sig/sql-infra SIG: SQL Infra labels Feb 25, 2022
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ti-chi-bot commented Feb 25, 2022

[REVIEW NOTIFICATION]

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@ti-chi-bot ti-chi-bot added release-note-none Denotes a PR that doesn't merit a release note. do-not-merge/needs-triage-completed size/XS Denotes a PR that changes 0-9 lines, ignoring generated files. labels Feb 25, 2022
@ti-chi-bot ti-chi-bot added the status/LGT1 Indicates that a PR has LGTM 1. label Feb 25, 2022
@ti-chi-bot ti-chi-bot added needs-cherry-pick-release-5.4 Should cherry pick this PR to release-5.4 branch. and removed do-not-merge/needs-triage-completed labels Feb 25, 2022
@zimulala zimulala removed the needs-cherry-pick-release-5.4 Should cherry pick this PR to release-5.4 branch. label Feb 25, 2022
@ti-chi-bot ti-chi-bot added the needs-cherry-pick-release-5.4 Should cherry pick this PR to release-5.4 branch. label Feb 25, 2022
@zimulala zimulala added the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label Feb 25, 2022
@ti-chi-bot ti-chi-bot added needs-cherry-pick-release-5.0 needs-cherry-pick-release-5.1 needs-cherry-pick-release-5.2 needs-cherry-pick-release-5.3 Type: Need cherry pick to release-5.3 and removed do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. labels Mar 2, 2022
@zimulala zimulala force-pushed the zimuxia/list-partition branch from 5f0b870 to 3995ef8 Compare March 2, 2022 06:25
@ti-chi-bot ti-chi-bot added size/M Denotes a PR that changes 30-99 lines, ignoring generated files. and removed size/XS Denotes a PR that changes 0-9 lines, ignoring generated files. labels Mar 2, 2022
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sre-bot commented Mar 2, 2022

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zimulala commented Mar 2, 2022

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zimulala commented Mar 3, 2022

/merge

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

Commit hash: 3995ef8

@ti-chi-bot ti-chi-bot added the status/can-merge Indicates a PR has been approved by a committer. label Mar 3, 2022
@ti-chi-bot ti-chi-bot added release-note Denotes a PR that will be considered when it comes time to generate release notes. and removed release-note-none Denotes a PR that doesn't merit a release note. labels Mar 3, 2022
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/run-unit-test

@ti-chi-bot ti-chi-bot merged commit 0e4084c into pingcap:master Mar 3, 2022
ti-srebot pushed a commit to ti-srebot/tidb that referenced this pull request Mar 3, 2022
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cherry pick to release-5.0 in PR #32768

ti-srebot pushed a commit to ti-srebot/tidb that referenced this pull request Mar 3, 2022
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cherry pick to release-5.1 in PR #32769

ti-srebot pushed a commit to ti-srebot/tidb that referenced this pull request Mar 3, 2022
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cherry pick to release-5.2 in PR #32770

ti-srebot pushed a commit to ti-srebot/tidb that referenced this pull request Mar 3, 2022
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cherry pick to release-5.3 in PR #32771

ti-srebot pushed a commit to ti-srebot/tidb that referenced this pull request Mar 3, 2022
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cherry pick to release-5.4 in PR #32772

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needs-cherry-pick-release-5.0 needs-cherry-pick-release-5.1 needs-cherry-pick-release-5.2 needs-cherry-pick-release-5.3 Type: Need cherry pick to release-5.3 needs-cherry-pick-release-5.4 Should cherry pick this PR to release-5.4 branch. release-note Denotes a PR that will be considered when it comes time to generate release notes. sig/sql-infra SIG: SQL Infra size/M Denotes a PR that changes 30-99 lines, ignoring generated files. status/can-merge Indicates a PR has been approved by a committer. status/LGT2 Indicates that a PR has LGTM 2. type/bugfix This PR fixes a bug.
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v5.4.0 list partition can't work after restarting tidb
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