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Process streams of partition tables one by one in MultiplexInputStream (#8507)#8520

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ti-chi-bot[bot] merged 4 commits intopingcap:release-7.5from
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Dec 14, 2023
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Process streams of partition tables one by one in MultiplexInputStream (#8507)#8520
ti-chi-bot[bot] merged 4 commits intopingcap:release-7.5from
ti-chi-bot:cherry-pick-8507-to-release-7.5

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@ti-chi-bot ti-chi-bot commented Dec 14, 2023

This is an automated cherry-pick of #8507

What problem does this PR solve?

Issue Number: close #8505

Problem Summary:
See #8505.

What is changed and how it works?

In the previous code, many streams of different partition tables may be processed concurrently. This PR simply fixes it by processing streams of partition tables one by one.

Check List

Tests

  • Unit test
  • Integration test
  • Manual test (add detailed scripts or steps below)
  • No code

create a table with 36 partitions.
Test SQL select * from employees.

mysql> explain analyze select * from employees;
+-------------------------+--------------+-----------+--------------+-----------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------------------------------------+---------+------+
| id                      | estRows      | actRows   | task         | access object   | execution info                                                                                                                                                                                                                                                                                                                                                                                                    | operator info                             | memory  | disk |
+-------------------------+--------------+-----------+--------------+-----------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------------------------------------+---------+------+
| TableReader_11          | 436207616.00 | 603979776 | root         | partition:all   | time:13.4s, loops:590554, RU:0.000000, cop_task: {num: 10160, max: 0s, min: 0s, avg: 0s, p95: 0s, copr_cache_hit_ratio: 0.00}                                                                                                                                                                                                                                                                                     | MppVersion: 1, data:ExchangeSender_10     | 7.92 MB | N/A  |
| └─ExchangeSender_10     | 436207616.00 | 603979776 | mpp[tiflash] |                 | tiflash_task:{proc max:12.9s, min:12.6s, avg: 12.7s, p80:12.9s, p95:12.9s, iters:10283, tasks:2, threads:72}                                                                                                                                                                                                                                                                                                      | ExchangeType: PassThrough                 | N/A     | N/A  |
|   └─TableFullScan_9     | 436207616.00 | 603979776 | mpp[tiflash] | table:employees | tiflash_task:{proc max:137.4ms, min:121ms, avg: 129.2ms, p80:137.4ms, p95:137.4ms, iters:10283, tasks:2, threads:72}, tiflash_scan:{dtfile:{total_scanned_packs:94981, total_skipped_packs:15416, total_scanned_rows:774644749, total_skipped_rows:125859659, total_rs_index_load_time: 0ms, total_read_time: 35296ms}, total_create_snapshot_time: 3ms, total_local_region_num: 972, total_remote_region_num: 0} | keep order:false, PartitionTableScan:true | N/A     | N/A  |
+-------------------------+--------------+-----------+--------------+-----------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------------------------------------+---------+------+
3 rows in set (13.45 sec)
image

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

Fix potential OOM when scanning many partition tables with stream model.

@gengliqi @ti-chi-bot
This is an automated cherry-pick of pingcap#8507
e9d8180 
Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>
@ti-chi-bot ti-chi-bot added release-note Denotes a PR that will be considered when it comes time to generate release notes. size/L Denotes a PR that changes 100-499 lines, ignoring generated files. type/cherry-pick-for-release-7.5 This PR is cherry-picked to release-7.5 from a source PR. labels Dec 14, 2023
@ti-chi-bot ti-chi-bot mentioned this pull request Dec 14, 2023
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@ti-chi-bot ti-chi-bot added the cherry-pick-approved Cherry pick PR approved by release team. label Dec 14, 2023
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fix conflict
be91d1d 
Signed-off-by: gengliqi <gengliqiii@gmail.com>
@ti-chi-bot ti-chi-bot bot added size/M Denotes a PR that changes 30-99 lines, ignoring generated files. and removed size/L Denotes a PR that changes 100-499 lines, ignoring generated files. labels Dec 14, 2023
@ti-chi-bot ti-chi-bot bot added needs-1-more-lgtm Indicates a PR needs 1 more LGTM. approved labels Dec 14, 2023
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ti-chi-bot bot commented Dec 14, 2023

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gengliqi, SeaRise

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@ti-chi-bot ti-chi-bot bot added lgtm and removed needs-1-more-lgtm Indicates a PR needs 1 more LGTM. labels Dec 14, 2023
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ti-chi-bot bot commented Dec 14, 2023

[LGTM Timeline notifier]

Timeline:

  • 2023-12-14 09:40:55.007157177 +0000 UTC m=+521946.044384102: ☑️ agreed by gengliqi.
  • 2023-12-14 09:45:01.739942118 +0000 UTC m=+522192.777169030: ☑️ agreed by SeaRise.

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gengliqi commented Dec 14, 2023

/run-all-tests

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ti-chi-bot bot commented Dec 14, 2023

@ti-chi-bot: Your PR was out of date, I have automatically updated it for you.

At the same time I will also trigger all tests for you:

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gengliqi commented Dec 14, 2023

/run-unit-test

@ti-chi-bot ti-chi-bot bot merged commit f68e662 into pingcap:release-7.5 Dec 14, 2023
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