Re: [pgsql-admin] JCR (Apache Jackrabbit) locking when using Postgres, not with MySQL - Mailing list pgsql-admin

From Gary Webster
Subject Re: [pgsql-admin] JCR (Apache Jackrabbit) locking when using Postgres, not with MySQL
Date
Msg-id CAEHjwJ6tERTxW0=aTuO3mcr0DrCGTjJHvLLWEAgqEEgTtWQP7Q@mail.gmail.com
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In response to [pgsql-admin] JCR (Apache Jackrabbit) locking when using Postgres, not with MySQL  (Gary Webster <gary.webster@perceptivesoftware.com>)
List pgsql-admin
On Thu, Aug 30, 2012 at 3:33 AM, Albe Laurenz <laurenz.albe@wien.gv.at> wrote:
Gary Webster wrote:
> The subject says most of what I know at this point.
>
> We are still not getting along with Apache Jackrabbit.
> After a few hours of using Postgres as the Persistence Manager, the
JCR gets stuck, apparently on a
> simple DB update statement.
>
> This problem does not occur at all if we substitute MySQL!
>
> This is Postgres v9.1.3 on RHEL5, 64-bit.

If you want to know if there are locking issues
in the database, examine pg_locks and pg_stat_activity.

If you use MyISAM in MySQL, it is not surprising that
you have no locking issues, since no effort is made to
ascertain data integrity.

Yours,
Laurenz Albe

Hello.
Thanks for the info.

I responded about pg_stat_activity in my other post.
The only interesting activity I see is this:
"update JOURNAL_LOCAL_REVISIONS set REVISION_ID = $1 where JOURNAL_ID = $2"

I don't know exactly what I'm looking for in pg_locks .

MySQL works OK with both MyISAM & InnoDB.

Here is some info from the JCR side:
I see these two log statements with Postgres and MySQL in which case they both halt...
 INFO - http-8080-35 - org.apache.jackrabbit.core.journal.AbstractJournal - Record with revision '20942' created by this journal, skipped.
 INFO - http-8080-35 - org.apache.jackrabbit.core.journal.AbstractJournal - Synchronized to revision: 20942
Then, MySQL 'breaks free' but Postgres does not.


We are using JDBC, though I'm not sure where I should be getting that from...

version: PostgreSQL 9.1.3 on x86_64-unknown-linux-gnu, compiled by gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-46), 64-bit
This install came from EnterpriseDB package.
The hardware has 8 CPU cores, & 12GB RAM.
I am using autovacuum, with "autovacuum_vacuum_cost_limit = 500" .

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