SI-9157 Avoid exponential blowup with chained type projections #4341
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
retronym
force-pushed
the
ticket/9157
branch
3 times, most recently
from
6e4cba8
to
b826f9e
Compare
Calling `findMember` in the enclosed test was calling into `NonClassTypeRef#relativeInfo` an exponentially-increasing number of times, with respect to the length of the chained type projections. The numbers of calls increased as: 26, 326, 3336, 33446, 334556. Can any pattern spotters in the crowd that can identify the sequence? (I can't.) Tracing the calls saw we were computing the same `memberType` repeatedly. This part of the method was not guarded by the cache. I have changed the method to use the standard idiom of using the current period for cache invalidation. The enclosed test now compiles promptly, rather than in geological time.
retronym
force-pushed
the
ticket/9157
branch
from
b826f9e
to
b6cbee9
Compare
|
Review by @adriaanm |
|
Here's an iterative formula for the pattern: |
|
LGTM! I can feel the tectonic plates zipping past! Chrome feels snappier too! And I haven't even merged! And, @jrudolph, wow -- just wow! |
adriaanm
added a commit
that referenced
this pull request
Feb 18, 2015
SI-9157 Avoid exponential blowup with chained type projections
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Outdated suggestions cannot be applied.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.
Calling
findMemberin the enclosed test was calling intoNonClassTypeRef#relativeInfoan exponentially-increasing numberof times, with respect to the length of the chained type projections.
The numbers of calls increased as: 26, 326, 3336, 33446, 334556.
Can any pattern spotters in the crowd that can identify the
sequence? (I can't.)
Tracing the calls saw we were computing the same
memberTyperepeatedly. This part of the method was not guarded by the cache.
I have changed the method to use the standard idiom of using the
current period for cache invalidation. The enclosed test now compiles
promptly, rather than in geological time.