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Process streams of partition tables one by one in MultiplexInputStream#8507

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gengliqi:fix-multiplex
Dec 14, 2023
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Process streams of partition tables one by one in MultiplexInputStream#8507
ti-chi-bot[bot] merged 10 commits intopingcap:masterfrom
gengliqi:fix-multiplex

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@gengliqi gengliqi commented Dec 12, 2023 •
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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 under stream model.

@gengliqi
process streams of partition tables one by one
b0b6304 
Signed-off-by: gengliqi <gengliqiii@gmail.com>
@ti-chi-bot ti-chi-bot bot added release-note-none Denotes a PR that doesn't merit a release note. size/M Denotes a PR that changes 30-99 lines, ignoring generated files. labels Dec 12, 2023
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gengliqi commented Dec 12, 2023

/run-all-tests

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windtalker commented Dec 13, 2023

Can you do some manual tests to show the memory usage with/without this pr?

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LGTM

@ti-chi-bot ti-chi-bot bot added needs-1-more-lgtm Indicates a PR needs 1 more LGTM. approved labels Dec 13, 2023
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gengliqi commented Dec 13, 2023

/run-all-tests

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address comment
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Signed-off-by: gengliqi <gengliqiii@gmail.com>
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update
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Signed-off-by: gengliqi <gengliqiii@gmail.com>
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LGTM

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ti-chi-bot bot commented Dec 14, 2023

[APPROVALNOTIFIER] This PR is APPROVED

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

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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:

  • 2023-12-13 05:25:19.953213337 +0000 UTC m=+420210.990440264: ☑️ agreed by SeaRise.
  • 2023-12-14 07:21:30.762528321 +0000 UTC m=+513581.799755248: ☑️ agreed by windtalker.

@ti-chi-bot ti-chi-bot 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 Dec 14, 2023
@gengliqi gengliqi added needs-cherry-pick-release-6.5 Should cherry pick this PR to release-6.5 branch. needs-cherry-pick-release-7.1 Should cherry pick this PR to release-7.1 branch. needs-cherry-pick-release-7.5 Should cherry pick this PR to release-7.5 branch. labels Dec 14, 2023
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gengliqi commented Dec 14, 2023

/unhold

@ti-chi-bot ti-chi-bot bot added size/L Denotes a PR that changes 100-499 lines, ignoring generated files. do-not-merge/needs-triage-completed and removed size/M Denotes a PR that changes 30-99 lines, ignoring generated files. do-not-merge/hold Indicates that a PR should not merge because someone has issued a /hold command. do-not-merge/needs-triage-completed labels Dec 14, 2023
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gengliqi commented Dec 14, 2023

/run-all-tests

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gengliqi commented Dec 14, 2023

/run-unit-test

@ti-chi-bot ti-chi-bot bot merged commit d344d9a into pingcap:master Dec 14, 2023
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ti-chi-bot commented Dec 14, 2023

In response to a cherrypick label: new pull request created to branch release-7.5: #8520.

ti-chi-bot pushed a commit to ti-chi-bot/tiflash that referenced this pull request Dec 14, 2023
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This is an automated cherry-pick of pingcap#8507
e9d8180 
Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>
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ti-chi-bot commented Dec 14, 2023

In response to a cherrypick label: new pull request created to branch release-6.5: #8521.

ti-chi-bot pushed a commit to ti-chi-bot/tiflash that referenced this pull request Dec 14, 2023
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This is an automated cherry-pick of pingcap#8507
1241207 
Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>
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ti-chi-bot commented Dec 14, 2023

In response to a cherrypick label: new pull request created to branch release-7.1: #8522.

ti-chi-bot pushed a commit to ti-chi-bot/tiflash that referenced this pull request Dec 14, 2023
@gengliqi @ti-chi-bot
This is an automated cherry-pick of pingcap#8507
defdc3e 
Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>
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Process streams of partition tables one by one in MultiplexInputStream (
4c26c00 
#8507) (#8521)

close #8505
ti-chi-bot bot pushed a commit that referenced this pull request Dec 14, 2023
@ti-chi-bot
Process streams of partition tables one by one in MultiplexInputStream (
f68e662 
#8507) (#8520)

close #8505
ti-chi-bot added a commit to ti-chi-bot/tiflash that referenced this pull request Dec 15, 2023
@ti-chi-bot
Process streams of partition tables one by one in MultiplexInputStream (
19825ad 
pingcap#8507) (pingcap#8521)

close pingcap#8505
@ti-chi-bot ti-chi-bot mentioned this pull request Dec 15, 2023
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yibin87 pushed a commit to yibin87/tiflash that referenced this pull request Dec 15, 2023
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Process streams of partition tables one by one in MultiplexInputStream (
7b85fc9 
pingcap#8507)

close pingcap#8505
ti-chi-bot bot pushed a commit that referenced this pull request Dec 15, 2023
@ti-chi-bot
Process streams of partition tables one by one in MultiplexInputStream (
e4a30bc 
#8507) (#8522)

close #8505
ti-chi-bot bot pushed a commit that referenced this pull request Dec 15, 2023
@ti-chi-bot
Process streams of partition tables one by one in MultiplexInputStream (
913134e 
#8507) (#8521) (#8527)

close #8505
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@windtalker windtalker windtalker approved these changes

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TiFlash may be OOM when scanning many partition tables under stream model

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