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Posted to issues@hive.apache.org by "Peter Varga (Jira)" <ji...@apache.org> on 2020/11/03 08:43:00 UTC
[jira] [Resolved] (HIVE-24291) Compaction Cleaner prematurely
cleans up deltas
[ https://issues.apache.org/jira/browse/HIVE-24291?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Peter Varga resolved HIVE-24291.
--------------------------------
Fix Version/s: 4.0.0
Resolution: Fixed
> Compaction Cleaner prematurely cleans up deltas
> -----------------------------------------------
>
> Key: HIVE-24291
> URL: https://issues.apache.org/jira/browse/HIVE-24291
> Project: Hive
> Issue Type: Bug
> Reporter: Peter Varga
> Assignee: Peter Varga
> Priority: Major
> Labels: pull-request-available
> Fix For: 4.0.0
>
> Time Spent: 1h 50m
> Remaining Estimate: 0h
>
> Since HIVE-23107 the cleaner can clean up deltas that are still used by running queries.
> Example:
> * TxnId 1-5 writes to a partition, all commits
> * Compactor starts with txnId=6
> * Long running query starts with txnId=7, it sees txnId=6 as open in its snapshot
> * Compaction commits
> * Cleaner runs
> Previously min_history_level table would have prevented the Cleaner to delete the deltas1-5 until txnId=7 is open, but now they will be deleted and the long running query may fail if its tries to access the files.
> Solution could be to not run the cleaner until any txn is open that was opened before the compaction was committed (CQ_NEXT_TXN_ID)
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