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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 14:25:50 GMT

    [ https://issues.apache.org/jira/browse/DERBY-3098?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12532123
] 

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

I was wrong about Clob not using OverflowInputStream.  It does.  (I
had an error in my test program so that it was fetching a Clob that
was not large enough for OverflowInputStream to come into play.)

The problem I have is that locks are not released after free() for
Clob.  I think the problem is that it is obtaining two sets of locks,
but only releasing one set.  My theory is that in the EmbedClob constructor,
both 
     ((Resetable) storeStream).initStream();
and
     this.clob = new StoreStreamClob(storeStream, this);
causes locks to be set.


> 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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