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https://issues.apache.org/jira/browse/JCR-2892?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13119959#comment-13119959
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Danilo Ghirardelli commented on JCR-2892:
-----------------------------------------
The linked issue JCR-3090 addressed the same issue in a different way: every
call to the "reallyExec" method (where the setFetchSize is set) has the maxRows
value set to 0, so the patch for that issue is simply indirectly disabling the
fetch size hint. This would probably solve the problem of this issue but will
probably re-open the problem stated in JCR-2832.
By the way, just like Manuel, I also used Magnolia CMS (with clustering) on
Tomcat to reproduce the problem.
> Large fetch sizes have potentially deleterious effects on VM memory
> requirements when using Oracle
> --------------------------------------------------------------------------------------------------
>
> Key: JCR-2892
> URL: https://issues.apache.org/jira/browse/JCR-2892
> Project: Jackrabbit Content Repository
> Issue Type: Bug
> Components: jackrabbit-core, sql
> Affects Versions: 2.2.2
> Environment: Oracle 10g+
> Reporter: Christopher Elkins
> Attachments: oracleFetchSize.patch
>
>
> Since Release 10g, Oracle JDBC drivers use the fetch size to allocate buffers
> for caching row data.
> cf. http://www.oracle.com/technetwork/database/enterprise-edition/memory.pdf
> r1060431 hard-codes the fetch size for all ResultSet-returning statements to
> 10,000. This value has significant, potentially deleterious, effects on the
> heap space required for even moderately-sized repositories. For example, the
> BUNDLE table (from 'oracle.ddl') has two columns -- NODE_ID raw(16) and
> BUNDLE_DATA blob -- which require 16 b and 4 kb of buffer space,
> respectively. This requires a buffer of more than 40 mb [(16+4096) * 10000 =
> 41120000].
> If the issue described in JCR-2832 is truly specific to PostgreSQL, I think
> its resolution should be moved to a PostgreSQL-specific ConnectionHelper
> subclass. Failing that, there should be a way to override this hard-coded
> value in OracleConnectionHelper.
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