Don't rewrite parts not touched by mutations #2694
Merged
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Outdated suggestions cannot be applied.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.
Apparently the easiest way to use MergeTree indexes when mutating parts is to use the full InterpreterSelectQuery machinery. For that to work a fake storage was implemented that reads only from a single MergeTree part (
StorageFromMergeTreeDataPart
).The parts that are not touched are copied using
localBackup()
and not simply renamed to avoid difficulties when status of the part commit operation in ZooKeeper is unknown.