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Posted to commits@druid.apache.org by GitBox <gi...@apache.org> on 2021/08/06 20:31:56 UTC
[GitHub] [druid] will-lauer opened a new pull request #11559: Lazy processing of spill files to avoid "Too many open files" errors
will-lauer opened a new pull request #11559:
URL: https://github.com/apache/druid/pull/11559
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Fixes #11558.
### Description
Solve the "Too many open files" problem in some groupBy queries by lazily opening spill files instead of opening them all at once.
Changing `SpillingGrouper` to use a new `LazyCloseableIterator` to lazily open spill files only when actually ready to consume their contents. In `SpillingGrouper.read()`, return a `Provider` that constructs the necessary `MappingIterator` instead of returning the `MappingIterator` itself. This allows a lambda to be used to capture the file, but postpone processing it until actually needed.
#### Fixed the bug #11558
<hr>
##### Key changed/added classes in this PR
* `SpillingGrouper`
* `LazyCloseableIterator`
<hr>
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This PR has:
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- [ ] been tested in a test Druid cluster.
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[GitHub] [druid] will-lauer closed pull request #11559: Lazy processing of spill files to avoid "Too many open files" errors
Posted by GitBox <gi...@apache.org>.
will-lauer closed pull request #11559:
URL: https://github.com/apache/druid/pull/11559
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[GitHub] [druid] will-lauer commented on pull request #11559: Lazy processing of spill files to avoid "Too many open files" errors
Posted by GitBox <gi...@apache.org>.
will-lauer commented on pull request #11559:
URL: https://github.com/apache/druid/pull/11559#issuecomment-902731790
Unfortunately, this doesn't solve the problem, so closing PR
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[GitHub] [druid] will-lauer commented on pull request #11559: Lazy processing of spill files to avoid "Too many open files" errors
Posted by GitBox <gi...@apache.org>.
will-lauer commented on pull request #11559:
URL: https://github.com/apache/druid/pull/11559#issuecomment-895637752
Unfortunately, as mentioned in #11558, this does not solve most cases of this problem, as sorting triggers opening all the files anyway, even if they are loaded lazily.
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