Make cache eviction write-back optional per repository#32
Merged
Conversation
Evicted cache entries always get written back to Mongo, which causes problems when multiple processes share a database - a stale cached copy can resurrect documents another process deleted, or clobber newer writes since the write-back is a full-document upsert. Repositories can now pass saveOnEviction=false to opt out. The existing constructors keep the old behaviour.
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
1 participant
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
The removal listener in
Repositorywrites entries back to Mongo whenever they leave the cache for any reason other than explicit removal or replacement. That's fine for a single process, but when multiple processes share a database it can resurrect documents another process deleted, or overwrite newer data with a stale cached copy (the write-back is a full-document$setupsert).This adds a
saveOnEvictionflag through a new constructor overload so a repository can opt out of the write-back. The two existing constructors delegate withtrue, so nothing changes for current consumers or forRepositoryManager's reflective instantiation.Also adds tests for the removal listener: eviction saves with write-back enabled (both via the old constructor and an explicit
true), doesn't save when disabled, and explicit removal never saves in either mode.mvn clean verifypasses.