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Storage: Refactor DMFileReader #8854

Merged
merged 28 commits into from
Apr 3, 2024
Merged

Storage: Refactor DMFileReader #8854

merged 28 commits into from
Apr 3, 2024

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Lloyd-Pottiger
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@Lloyd-Pottiger Lloyd-Pottiger commented Mar 20, 2024 •
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What problem does this PR solve?

Issue Number: ref #6233

Problem Summary:

What is changed and how it works?

Refactor DMFileReader to make life easier~

Separate the packs can do clean read.

Check List

Tests

  • Unit test
  • Integration test
  • Manual test (add detailed scripts or steps below)
  • 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

None

@ti-chi-bot ti-chi-bot bot added release-note-none Denotes a PR that doesn't merit a release note. size/L Denotes a PR that changes 100-499 lines, ignoring generated files. labels Mar 20, 2024
@ti-chi-bot ti-chi-bot bot added size/XXL Denotes a PR that changes 1000+ lines, ignoring generated files. and removed size/L Denotes a PR that changes 100-499 lines, ignoring generated files. labels Mar 20, 2024
@Lloyd-Pottiger
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/run-all-tests

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/run-integration-test

CalvinNeo
CalvinNeo reviewed Mar 25, 2024
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dbms/src/Storages/DeltaMerge/File/ColumnCache.cpp
{
PackRange target_range{start_pack_id, start_pack_id + pack_count};

RangeWithStrategys range_and_strategys;
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Strategies

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keep this, it means multiple RangeWithStrategy

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I don't think it is a good idea, Poco is an example.
image

However, I think it isn't a big matter, don't take this as a serious review. Just my point of view.

@Lloyd-Pottiger
refactor
b03deeb 
Signed-off-by: Lloyd-Pottiger <[email protected]>
@Lloyd-Pottiger
address
cb7bcd0 
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@Lloyd-Pottiger
address
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address
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JaySon-Huang
JaySon-Huang reviewed Mar 26, 2024
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dbms/src/Storages/DeltaMerge/File/DMFileReader.h Outdated
@@ -142,7 +154,7 @@ class DMFileReader
/// Filters
DMFilePackFilter pack_filter;

std::vector<size_t> skip_packs_by_column{};
std::vector<bool> must_seek;
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avoid using std::vector<bool>

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DMFileReader will be created for each segment in a query. If multiple queries are running at the same time, a lot of DMFileReader will be created. And if there are cop tasks, it is even worse. So reducing memory is important for DMFileReader.

And since must_seek is a private member, which means it only can be accessed inside, so no outer reference refers to it, meanwhile, the life cycle of the inside reference will always shorter than must_seek itself. So it is safe.

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Why not use bitset?

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std::bitset can not decide size in run time. std::vecotr<bool> is safe in this case.

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How about boost::dynamic_bitset? It is dynamic. Moreover, it supports efficient batch set bits (while std::fill(std::vector<bool>) does not stipulate its complexity and may have poor performance in some stds)

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boost::dynamic_bitset::operator[] also return a reference.

Anyway, must_seek is removed.

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/run-build-release

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sre-bot commented Mar 29, 2024

download tiflash binary(linux amd64) at http://fileserver.pingcap.net/download/builds/pingcap/test/tiflash/38e747a896302ec18787acfb713375a1d9532453/centos7/tiflash-linux-amd64.tar.gz

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move to private
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Maintaining must_seek makes the code seem cumbersome and odd.

According to the code, the cost of seek is negligible if we don't really need to seek. Maybe we can remove must_seek and just seek every time before reading from disk.

https://github.com/pingcap/tiflash/blob/master/dbms/src/IO/Compression/CompressedReadBufferFromFile.cpp#L54-L83

Totally agree, I will remove it.

@Lloyd-Pottiger
remove must_seek
9458001 
Signed-off-by: Lloyd-Pottiger <[email protected]>
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format
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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 Apr 2, 2024
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ti-chi-bot bot commented Apr 2, 2024

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: CalvinNeo, JinheLin

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ti-chi-bot bot commented Apr 2, 2024

[LGTM Timeline notifier]

Timeline:

  • 2024-03-29 05:19:24.500723741 +0000 UTC m=+2217991.522970124: ☑️ agreed by CalvinNeo.
  • 2024-04-02 09:14:02.327854737 +0000 UTC m=+348903.855395281: ☑️ agreed by JinheLin.

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ti-chi-bot bot commented Apr 2, 2024

@Lloyd-Pottiger: 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:

/run-all-tests

trigger some heavy tests which will not run always when PR updated.

If the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

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/hold

@ti-chi-bot ti-chi-bot bot added the do-not-merge/hold Indicates that a PR should not merge because someone has issued a /hold command. label Apr 2, 2024
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fix tidy
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/run-all-tests

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/run-unit-test

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/unhold

@ti-chi-bot ti-chi-bot bot removed the do-not-merge/hold Indicates that a PR should not merge because someone has issued a /hold command. label Apr 3, 2024
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/run-all-tests

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/run-unit-test

@ti-chi-bot ti-chi-bot bot merged commit 238e43c into pingcap:master Apr 3, 2024
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@Lloyd-Pottiger Lloyd-Pottiger deleted the refactor-dmfile branch April 8, 2024 02:54
JaySon-Huang added a commit that referenced this pull request Apr 8, 2024
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Revert "Storage: Refactor DMFileReader (#8854)"
c0ca459 
This reverts commit 238e43c.
This was referenced Apr 8, 2024
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@Lloyd-Pottiger Lloyd-Pottiger mentioned this pull request Apr 10, 2024
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@JaySon-Huang JaySon-Huang JaySon-Huang left review comments

@breezewish breezewish breezewish left review comments

@JinheLin JinheLin JinheLin approved these changes

@CalvinNeo CalvinNeo CalvinNeo approved these changes

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