Solve inconsistent hashing behavior #45
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
In a dynamic cluster (adding and removing nodes), there is a chance when dividing we receive an infinite repeating result which floors to a value that would be less than it needs to be to maintain a consistent hash with a prior state (in which the dividing result is a full integer, or not repeating). Using round here seems to resolve the issue. Test case: create a cluster of 6, distribute keys, add a new pnode (total 7), redistribute keys, add a new pnode (total 8), redistribute keys and then run through all keys and check that they exist in the correct location (failure).
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Outdated suggestions cannot be applied.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.
In a dynamic cluster (adding and removing nodes), there is a chance when dividing we receive an infinite repeating result which floors to a value that would be less than it needs to be to maintain a consistent hash with a prior state (in which the dividing result is a full integer, or not repeating).
Using round here seems to resolve the issue.
Test case: create a cluster of 6, distribute keys, add a new pnode (total 7), redistribute keys, add a new pnode (total 8), redistribute keys and then run through all keys and check that they exist in the correct location (failure).
solves issue #43