fix: Resolve race condition of Duchy claimTask in spanner implementation. #1726
Conversation
This file contains 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
|
This change is |
renjiezh
changed the title
SanjayVas
approved these changes
Jul 31, 2024
There was a problem hiding this comment.
Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status:complete! all files reviewed, all discussions resolved (waiting on @renjiezh)
stevenwarejones
approved these changes
Aug 1, 2024
There was a problem hiding this comment.
Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status:
SanjayVas
pushed a commit
that referenced
this pull request
Aug 2, 2024
renjiezh
added a commit
that referenced
this pull request
Aug 8, 2024
For some additional context, this is mostly reverting #1726. Using a single transaction can result in a lock contention issue, as the unclaimed tasks query will lock all claimable Computations DB rows. The solution is to use a separate transaction to perform the write, but to re-read the single row and ensure that it's still claimable. The old version of this check had a flaw in that it incorrectly assumes that the JVM clock is monotonic. This PR introduces an additional check based on LockExpirationTime, which is less susceptible to clock skew.
ple13
pushed a commit
that referenced
this pull request
Aug 16, 2024
ple13
pushed a commit
that referenced
this pull request
Aug 16, 2024
For some additional context, this is mostly reverting #1726. Using a single transaction can result in a lock contention issue, as the unclaimed tasks query will lock all claimable Computations DB rows. The solution is to use a separate transaction to perform the write, but to re-read the single row and ensure that it's still claimable. The old version of this check had a flaw in that it incorrectly assumes that the JVM clock is monotonic. This PR introduces an additional check based on LockExpirationTime, which is less susceptible to clock skew.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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.
Issue #1722