Use a more exclusive lock for publishing tables #1387
Merged
Conversation
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
This was leading to quite reproducible deadlocks during publish. When the table is locked for share mode and two concurrenct transactions acquire the lock, t1 acquires a row exclusive lock on IsicId creation and waits for t2 that's just been opened in share mode to complete. When t2 then attempts to acquire a row exclusive lock to create an IsicId - t2 deadlocks because it recognizes that it's now waiting for t1. This modifies the code such that an exclusive lock is acquired, and reads are the only operations that can happen concurrently. This makes it such that every accession_publish call is effectively serialized.
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Outdated suggestions cannot be applied.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.
This was leading to quite reproducible deadlocks during publish. When
the table is locked for share mode and two concurrenct transactions
acquire the lock, t1 acquires a row exclusive lock on IsicId creation
and waits for t2 that's just been opened in share mode to complete. When
t2 then attempts to acquire a row exclusive lock to create an IsicId -
t2 deadlocks because it recognizes that it's now waiting for t1.
This modifies the code such that an exclusive lock is acquired, and
reads are the only operations that can happen concurrently. This makes
it such that every accession_publish call is effectively serialized.