[SPARK-13304] [SQL] Fix worst case of broadcast join of two ints#11188
Closed
davies wants to merge 1 commit intoapache:masterfrom
Closed
[SPARK-13304] [SQL] Fix worst case of broadcast join of two ints#11188davies wants to merge 1 commit intoapache:masterfrom
davies wants to merge 1 commit intoapache:masterfrom
Conversation
|
Test build #51201 has finished for PR 11188 at commit
|
davies
changed the title
|
Test build #51571 has finished for PR 11188 at commit
|
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
2 participants
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
If the two join columns have the same value, the hash code of them will be (a ^ b), which is 0, then the HashMap will be very very slow.
This PR will rotate the second int to avoid this case. In theory, it's still have the possibility that has lots of collisions, the pattern will be (1, 131072), (2, 131073) ... (n, n + 131072).
This PR also added some micro benchmark, and updated the results for broadcast hash joins.