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https://issues.apache.org/jira/browse/HIVE-26704?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Denys Kuzmenko updated HIVE-26704:
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Component/s: Transactions
> Cleaner shouldn't be blocked by global min open txnId
> -----------------------------------------------------
>
> Key: HIVE-26704
> URL: https://issues.apache.org/jira/browse/HIVE-26704
> Project: Hive
> Issue Type: Task
> Components: Transactions
> Reporter: Denys Kuzmenko
> Assignee: Denys Kuzmenko
> Priority: Major
> Labels: pull-request-available
> Fix For: 4.0.0-beta-1
>
> Time Spent: 6h 40m
> Remaining Estimate: 0h
>
> *Single transaction blocks cluster-wide Cleaner operations*
> Currently, if there is a single long-running transaction that can prevent the
> Cleaner to clean up any tables. This causes file buildup in tables, which can
> cause performance penalties when listing the directories (note that the
> compaction is not blocked by this, so unnecessary data is not read, but the
> files remain there which causes performance penalty).
> We can reduce the protected files from the open transaction if we have
> query-table correlation data stored in the backend DB, but this change will
> need the current method of recording that detail to be revisited.
> The naive and somewhat backward-compatible approach is to capture the
> minOpenWriteIds per table. It involves a non-mutation operation (as in, there
> is no need for the HMS DB to wait for another user’s operation to record it).
> This does spew data writes into the HMS backend DB, but this is a blind
> insert operation that can be group-committed across many users.
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