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[Enhancement] metadata support LRU memory evict strategy in shared-nothing cluster (backport #48832) #49170

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merged 2 commits into from
Jul 30, 2024

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@mergify mergify bot commented Jul 30, 2024

Why I'm doing:

In previous implementation, there is no memory limit for metadata in shared-nothing cluster. So if there are too many tablets and segment files, BE will OOM. We need a controllable metadata memory strategy.

What I'm doing:

Add a lru cache for metadata, its capacity is controlled by be.conf metadata_cache_memory_limit_percent.
When Rowset performs a load action, it adds the Rowset to the lru cache, and if the lru cache memory exceeds the limit, it selectively eliminates the loaded Rowset, ultimately realizing the goal of controllable metadata memory.
This strategy is only support non-pk table now.

There will be two cases when evict the Rowset:

  1. There is no reference hold by other user, Rowset's state will change from ROWSET_LOADED to ROWSET_UNLOADED , and then release the memory.
  2. There are reference hold by other user (e.g. compaction or query), Rowset's state will change from ROWSET_LOADED to ROWSET_UNLOADING. Memory will be release after compaction or query finish.

Test Result

image

  1. Before turning on LRU cache control strategy, metadata continues to increase without limit.
  2. After enabling LRU cache control strategy (with limit set to 1GB), metadata memory is stabilized at 1GB.

What type of PR is this:

  • BugFix
  • Feature
  • Enhancement
  • Refactor
  • UT
  • Doc
  • Tool

Does this PR entail a change in behavior?

  • Yes, this PR will result in a change in behavior.
  • No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

  • Interface/UI changes: syntax, type conversion, expression evaluation, display information
  • Parameter changes: default values, similar parameters but with different default values
  • Policy changes: use new policy to replace old one, functionality automatically enabled
  • Feature removed
  • Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

  • I have added test cases for my bug fix or my new feature
  • This pr needs user documentation (for new or modified features or behaviors)
    • I have added documentation for my new feature or new function
  • This is a backport pr

Bugfix cherry-pick branch check:

  • I have checked the version labels which the pr will be auto-backported to the target branch
    • 3.3
    • 3.2
    • 3.1
    • 3.0
    • 2.5

This is an automatic backport of pull request #48832 done by [Mergify](https://mergify.com). ## Why I'm doing: In previous implementation, there is no memory limit for `metadata` in shared-nothing cluster. So if there are too many tablets and segment files, BE will OOM. We need a controllable `metadata` memory strategy.

What I'm doing:

Add a lru cache for metadata, its capacity is controlled by be.conf metadata_cache_memory_limit_percent.
When Rowset performs a load action, it adds the Rowset to the lru cache, and if the lru cache memory exceeds the limit, it selectively eliminates the loaded Rowset, ultimately realizing the goal of controllable metadata memory.
This strategy is only support non-pk table now.

There will be two cases when evict the Rowset:

  1. There is no reference hold by other user, Rowset's state will change from ROWSET_LOADED to ROWSET_UNLOADED , and then release the memory.
  2. There are reference hold by other user (e.g. compaction or query), Rowset's state will change from ROWSET_LOADED to ROWSET_UNLOADING. Memory will be release after compaction or query finish.

Test Result

image

  1. Before turning on LRU cache control strategy, metadata continues to increase without limit.
  2. After enabling LRU cache control strategy (with limit set to 1GB), metadata memory is stabilized at 1GB.

What type of PR is this:

  • BugFix
  • Feature
  • Enhancement
  • Refactor
  • UT
  • Doc
  • Tool

Does this PR entail a change in behavior?

  • Yes, this PR will result in a change in behavior.
  • No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

  • Interface/UI changes: syntax, type conversion, expression evaluation, display information
  • Parameter changes: default values, similar parameters but with different default values
  • Policy changes: use new policy to replace old one, functionality automatically enabled
  • Feature removed
  • Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

  • I have added test cases for my bug fix or my new feature
  • This pr needs user documentation (for new or modified features or behaviors)
    • I have added documentation for my new feature or new function
  • This is a backport pr

…thing cluster (#48832)

Signed-off-by: luohaha <[email protected]>
(cherry picked from commit 0f639ad)

# Conflicts:
#	be/src/storage/CMakeLists.txt
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mergify bot commented Jul 30, 2024

Cherry-pick of 0f639ad has failed:

On branch mergify/bp/branch-3.2/pr-48832
Your branch is up to date with 'origin/branch-3.2'.

You are currently cherry-picking commit 0f639ad566.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   be/src/common/config.h
	new file:   be/src/storage/rowset/metadata_cache.cpp
	new file:   be/src/storage/rowset/metadata_cache.h
	modified:   be/src/storage/rowset/rowset.cpp
	modified:   be/src/storage/rowset/rowset.h
	modified:   be/src/storage/storage_engine.cpp
	modified:   be/src/storage/tablet_manager.cpp
	modified:   be/src/storage/tablet_manager.h
	modified:   be/src/util/starrocks_metrics.h
	modified:   be/test/CMakeLists.txt
	new file:   be/test/storage/rowset/metadata_cache_test.cpp
	modified:   be/test/storage/tablet_mgr_test.cpp

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   be/src/storage/CMakeLists.txt

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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mergify bot commented Jul 30, 2024

@mergify[bot]: Backport conflict, please reslove the conflict and resubmit the pr

@mergify mergify bot deleted the mergify/bp/branch-3.2/pr-48832 branch July 30, 2024 14:55
@luohaha luohaha restored the mergify/bp/branch-3.2/pr-48832 branch July 30, 2024 15:19
@luohaha luohaha reopened this Jul 30, 2024
@wanpengfei-git wanpengfei-git enabled auto-merge (squash) July 30, 2024 15:20
Signed-off-by: Yixin Luo <[email protected]>
@wanpengfei-git wanpengfei-git merged commit 4e55c60 into branch-3.2 Jul 30, 2024
28 of 29 checks passed
@wanpengfei-git wanpengfei-git deleted the mergify/bp/branch-3.2/pr-48832 branch July 30, 2024 16:00
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