Fix/serialization hash collision #35
Open
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
|
@axtimwalde @tpietzsch let me know if you have any thoughts, otherwise I'll plan to release this later this week, after using it a bit more |
It's actually slower in many cases, since hashcode calculation always iterates over all entries. Meanwhile, `compareTo` can return early if it's clear they are not equal.
refactor: Comparable<LabelMultisetEntryList> organization the `put` operation of `TreeMap` is expensive, since `compareTo` is expensive. So we want to reduce the number of calls to this. To that end we don't want to check equality BEFORE calling `put` since both will calculate `compareTo`. So we `putIfAbsent` on the list. However, the list at this point is a reference that can change, so we need to copy the data. But we don't want to always copy, since most lists (in most cases) are not unique, and we only need a single copy to reference in the `TreeMap`. So only copy the data `via addAll` when the list is a newly added one. In addition, move the `Comparable` implementation to a package-private subclass that also reuses a single ref from construction to do the comparison. smarter way of detecting when all entries are empty (`size()` was expensive, since it requires iterating over all entries)
cmhulbert
force-pushed
the
fix/serializationHashCollision
branch
from
a36f2d8
to
9d1de36
Compare
|
@axtimwalde some changes relevant to our conversation on Monday
Performance wise, it is a bit slower in the tests that are included in this library. In Paintera, with a real dataset it is only slightly slower on average (about 10%).
|
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Outdated suggestions cannot be applied.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.
There were some issues with occasional hash collisions when serializing LabelMultisetType images. This aims to solve in the following ways:
This lets us use a TreeMap in the serialization logic, instead of a HashMap. The comparator is sorted first by size to ensure smaller lists are checked for equality first.