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From Øystein Grøvlen (JIRA) <j...@apache.org>
Subject [jira] Commented: (DERBY-3098) LOB locks are not released after free().
Date Wed, 03 Oct 2007 14:04:50 GMT

    [ https://issues.apache.org/jira/browse/DERBY-3098?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12532113
] 

Øystein Grøvlen commented on DERBY-3098:
----------------------------------------

To Knut Anders question of READ UNCOMMITTED.  I have not tested it
yet, but I will add tests for that, too.

I assume we also for READ_UNCOMMITTED want the record of the Blob to
be locked since the Blob object should be stable regardless of
isolation level.  (I think this illustrate that locking the record is
not the best solution for guaranteeing stability, but creating a new
mechanism that allow more concurrency will be much more work.  More
work than I am willing to put into this.)


> LOB locks are not released after free().
> ----------------------------------------
>
>                 Key: DERBY-3098
>                 URL: https://issues.apache.org/jira/browse/DERBY-3098
>             Project: Derby
>          Issue Type: Bug
>          Components: Store
>    Affects Versions: 10.2.2.0, 10.3.1.4
>         Environment: Any
>            Reporter: Øystein Grøvlen
>            Assignee: Øystein Grøvlen
>         Attachments: derby-3098fix.diff
>
>
> When getBlob/getClob is called on the ResultSet, the current row is
> locked if the JDBC driver does not cache the entire LOB value in
> memory.  This is done to prevent the Blob/Clob object from being
> changed.  Until now, this lock has been held to the end of the
> transaction.
> JDBC4 introduced free() methods for the Blob/Clob class.  The locking
> should be changed so that the locks is releases when the Blob/Clob
> object is freed.

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