Fix DB iterator not resetting pauserehash causing dict being unable to rehash#12757
Merged
oranagra merged 2 commits intoredis:unstablefrom Nov 14, 2023
Merged
Fix DB iterator not resetting pauserehash causing dict being unable to rehash#12757oranagra merged 2 commits intoredis:unstablefrom
oranagra merged 2 commits intoredis:unstablefrom
Conversation
…o rehash When using DB iterator, it will use dictInitSafeIterator to init a old safe dict iterator. When dbIteratorNext is used, it will jump to the next slot db dict when we are done a dict. During this process, we do not have any calls to dictResumeRehashing, which causes the dict's pauserehash to always be > 0. And at last, it will be returned directly in dictRehashMilliseconds, which causes us to have slot dict in a state where rehash cannot be completed. In the "expire scan should skip dictionaries with lot's of empty buckets" test, adding a `keys *` can reproduce the problem stably. `keys *` will call dbIteratorNext to trigger a traversal of all slot dicts. Added dbReleaseIterator and dbIteratorInitNextSafeIterator methods to call dictResetIterator. Issue was introduced in redis#11695.
Contributor
|
Good catch! 👍 |
oranagra
approved these changes
Nov 14, 2023
Member
oranagra
left a comment
oranagra
left a comment
There was a problem hiding this comment.
thanks for finding this.
minor code arrangement comment before merging...
Contributor
|
good catch |
oranagra
approved these changes
Nov 14, 2023
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
When using DB iterator, it will use dictInitSafeIterator to init a old safe
dict iterator. When dbIteratorNext is used, it will jump to the next slot db
dict when we are done a dict. During this process, we do not have any calls to
dictResumeRehashing, which causes the dict's pauserehash to always be > 0.
And at last, it will be returned directly in dictRehashMilliseconds, which causes
us to have slot dict in a state where rehash cannot be completed.
In the "expire scan should skip dictionaries with lot's of empty buckets" test,
adding a
keys *can reproduce the problem stably.keys *will call dbIteratorNextto trigger a traversal of all slot dicts.
Added dbReleaseIterator function to call dictResetIterator.
Issue was introduced in #11695.