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https://issues.apache.org/jira/browse/JCR-2892?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13124950#comment-13124950
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Danilo Ghirardelli commented on JCR-2892:
-----------------------------------------
I'm sorry if I wasn't clear, but the value of 100 just worked for my
application (clustered Magnolia CMS), and it was the maximum fetchSize value
that allowed the application to start. Anyway, at 100 the memory occupation was
quite high, so maybe that value was good in my case but may crash in other
cases. Would it be possible to avoid setting a fetchSize at all (except for
postgresql)? Performance were always good and there was no problem until it was
set for the first time in JCR-2832...
> 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
> Assignee: Claus Köll
> Fix For: 2.2.10, 2.3.1
>
> Attachments: JCR-2892.patch, 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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