perf(schema): clear childSchemas when overwriting existing path to avoid performance degradations #15256
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
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Outdated suggestions cannot be applied.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.
Fix #15253
Summary
Currently, overwriting an existing recursive path using
Schema.prototype.path()leads to an exponential performance blowup because we're adding a separate recursive path tochildSchemason everypath()call. For example, in the test case added, the document has 1092 subdocuments, but with 2 duplicatechildSchemasentry Mongoose thinks there's over 56k subdocuments. With 3, Mongoose thinks there's about 560k subdocuments. I haven't been able to figure out a more complete explanation of the exact mathematical model of this growth, but suffice to say cleaning up duplicate childSchemas fixes the issue.Examples