Optimizing tsdb doc values codec merging #125887
Closed
Conversation
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
The doc values codec iterates a few times over the doc value instance that needs to be written to disk. In case when merging and index sorting is enabled, this is much more expensive, as each time the doc values instance is iterated an expensive doc id sorting is performed (in order to get the doc ids in order of index sorting). There are several reasons why the doc value instance is iterated multiple times: * To compute stats (num values, number of docs with value) required for writing values to disk. * To write bitset that indicate which documents have a value. (indexed disi, jump table) * To write the actual values to disk. * To write the addresses to disk (in case docs have multiple values) This applies for numeric doc values, but also for the ordinals of sorted (set) doc values. This PR addresses solving the first reason why doc value instance needs to be iterated. This is done only when in case of merging and when the segments to be merged with are also of type es87 doc values, codec version is the same and there are no deletes.
fixed sorted set dv added unit test with index sorting
…ctly in compatibleWithOptimizedMerge(...) method.
* Always store `numDocsWithField` and move it to `NumericEntry` * Use `TsdbDocValuesProducer` instead of EmptyDocValuesProducer where possible in ES87TSDBDocValuesConsumer * Fix TsdbDocValuesProducer#isSingleValued(...)
|
Running tsdb track (with force merge) without this change as baseline and with this change as contender: |
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Outdated suggestions cannot be applied.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.
Contains all changes mentioned in #125403