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https://issues.apache.org/jira/browse/SENTRY-1486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15573339#comment-15573339
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Alexander Kolbasov commented on SENTRY-1486:
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In Oracle classification "serializable" is the "repeatable reads" in MySQL. I
looked at the DB drivers in Datanucleus - they assume that Oracle support
repeatable reads, so they don't distinguish. They have a logic to move to a
higher level if a specific one isn't supported, so it would work correctly if
they don't mark repeatable-read as supported by Oracle. This means that we
can't rely on DN to do the right thing and should figure out how to make a
different setting for Oracle.
> Sentry should use repeatable-read consistency level
> ---------------------------------------------------
>
> Key: SENTRY-1486
> URL: https://issues.apache.org/jira/browse/SENTRY-1486
> Project: Sentry
> Issue Type: Bug
> Components: Sentry
> Affects Versions: 1.7.0, sentry-ha-redesign
> Reporter: Alexander Kolbasov
> Assignee: Alexander Kolbasov
> Fix For: 1.8.0
>
> Attachments: SENTRY-1486.001.patch, SENTRY-1486.002.patch
>
>
> Currently Sentry uses the "read-committed" consistency level which is the
> default for the Datanucleus JDO library. This causes potential problems since
> the state visible to each transaction can actually see updates from another
> transactions, so it is very difficult to reason about any code that reads
> multiple pieces of data.
> Instead it should use repeatable read" consistency which guarantees that any
> transaction only sees the state at the beginning of a transaction plus any
> updates done within a transaction.
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