[
https://issues.apache.org/jira/browse/JCR-2892?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13097151#comment-13097151
]
Manuel Molaschi commented on JCR-2892:
--------------------------------------
We have a different problem with the same cause... We experience a big
performance loss on an app built on Magnolia CMS and starting on Tomcat
(configured with xmx at 1024m)
After a long investigation we assumed that this behaviour was caused by jvm
spending a lot of time in GC (cpu usage was always very high)
These are the startup time on different jr versions / fetch size
with jr 2.2.1: 129 sec
with jr 2.2.8 (fetch size 10000): > 1h
with jr 2.2.8 (patch applied on ConnectionHelper to comment out
stmt.setFetchSize): 135 sec
> 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
>
> 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.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
