perf: cache missing XBlock mappings in load_class #813
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
Checking the entrypoints for the XBlock class we want for a given tag name is relatively expensive. We mitigate this by caching the mapping of tags to classes in Plugin.load_class(). But before this commit, we weren't caching failed lookups, i.e. the situation where there is no XBlock that maps to a given tag. This meant that if a course had many instances of a type of XBlock that is not installed on the given server, we would be constantly scanning entrypoints to look for our non-existent XBlock subclass. This really slows down things like the Studio course outline page. The fix here is to store failed lookups as None values in the PLUGIN_CACHE.
|
Fixes #811 FYI @openedx/interest-performance |
ormsbee
added
the
performance
5 tasks
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Outdated suggestions cannot be applied.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.
Checking the entrypoints for the XBlock class we want for a given tag name is relatively expensive. We mitigate this by caching the mapping of tags to classes in Plugin.load_class(). But before this commit, we weren't caching failed lookups, i.e. the situation where there is no XBlock that maps to a given tag. This meant that if a course had many instances of a type of XBlock that is not installed on the given server, we would be constantly scanning entrypoints to look for our non-existent XBlock subclass. This really slows down things like the Studio course outline page.
The fix here is to store failed lookups as None values in the PLUGIN_CACHE.