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Storage: Refactor DMContext to avoid being misused #8318

Merged
merged 8 commits into from
Nov 6, 2023
Merged

Storage: Refactor DMContext to avoid being misused #8318

merged 8 commits into from
Nov 6, 2023

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JaySon-Huang
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@JaySon-Huang JaySon-Huang commented Nov 6, 2023 •
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What problem does this PR solve?

Issue Number: close #8312

Problem Summary:

What is changed and how it works?

  • Rename DMContext::db_context to DMContext::global_context
  • Always save global_context as member in DMContext
  • Remove a lock in DeltaMergeStore::newDMContext that does not have concurrent issue in the latest code

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 do-not-merge/needs-linked-issue release-note-none Denotes a PR that doesn't merit a release note. size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. labels Nov 6, 2023
@JaySon-Huang JaySon-Huang changed the title Refactor DMContext to avoid being misused Storage: Refactor DMContext to avoid being misused Nov 6, 2023
JaySon-Huang
JaySon-Huang commented Nov 6, 2023
View reviewed changes
dbms/src/Storages/DeltaMerge/DeltaMergeStore.cpp
Comment on lines -452 to -453
std::shared_lock lock(read_write_mutex);

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@JaySon-Huang JaySon-Huang Nov 6, 2023 •
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The lock was added to protect the "schema" in very old versions(https://github.com/pingcap/tiflash/pull/507/files#diff-22b900e9e8020dc835612316f3bf151cae28b621bfac64d6a22b377d062f4b7eR165-R190). But now the members used in this function do not have concurrent issues. So this lock can be removed.

JaySon-Huang
JaySon-Huang commented Nov 6, 2023
View reviewed changes
dbms/src/Storages/DeltaMerge/DMContext.h
const String & tracing_id_ = "")
: db_context(db_context_)
: global_context(session_context_.getGlobalContext()) // always save the global context
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always save the global context no matter what the pass-in session_context is a session only context or global context, and rename it to be global_context

@JaySon-Huang JaySon-Huang mentioned this pull request Nov 6, 2023
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/run-all-tests

@ti-chi-bot ti-chi-bot bot added needs-1-more-lgtm Indicates a PR needs 1 more LGTM. approved labels Nov 6, 2023
@ti-chi-bot ti-chi-bot bot added the lgtm label Nov 6, 2023
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ti-chi-bot bot commented Nov 6, 2023

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: JinheLin, Lloyd-Pottiger

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@ti-chi-bot ti-chi-bot bot removed the needs-1-more-lgtm Indicates a PR needs 1 more LGTM. label Nov 6, 2023
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ti-chi-bot bot commented Nov 6, 2023

[LGTM Timeline notifier]

Timeline:

  • 2023-11-06 08:43:29.629790716 +0000 UTC m=+3461007.216900863: ☑️ agreed by JinheLin.
  • 2023-11-06 09:03:06.277928516 +0000 UTC m=+3462183.865038647: ☑️ agreed by Lloyd-Pottiger.

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/run-integration-test

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/run-integration-test

@ti-chi-bot ti-chi-bot bot merged commit ecb1eea into pingcap:master Nov 6, 2023
6 checks passed
@JaySon-Huang JaySon-Huang deleted the fix_dm_context_member branch November 6, 2023 13:25
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@Lloyd-Pottiger Lloyd-Pottiger Lloyd-Pottiger approved these changes

@JinheLin JinheLin JinheLin approved these changes

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Successfully merging this pull request may close these issues.

TiFlash crash in DM::SegmentReadTask::doFetchPages
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