[Building Sakai] Portfolio creation crash

[Sean Keesler]

I can't claim to be a performance expert. But I remember Charles
Hedrick remarking at the number of queries used to generate the XML
used in displaying a portfolio.

I wonder if the cache.osp.presentation.data property (SAK-14206) would
ease the db load...


Sean Keesler
130 Academy Street
Manlius, New York 13104 USA
315-663-7756
sean.keesler at threecanoes.com



On Tue, Sep 22, 2009 at 6:11 PM, Joshua Swink <joshua.swink at gmail.com> wrote:
> When several people try to create portfolios at the same time, Sakai
> crashes. I'm using version 2.6.0.
>
> The problems are:
>
> - Sakai crashes with connection pool errors. That is, it becomes
> unresponsive and Tomcat must be killed.
> - The pool, load balanced with mod_jk, becomes entirely unresponsive.
> The remaining Tomcats are fine (they can be accessed directly). When
> the misbehaving Tomcat is killed, the pool recovers and the other
> instances can be used again.
>
> Questions
>
> 1) Does anyone have insight into this error?
> 2) How can we make the pool continue to operate even when one Tomcat
> is misbehaving this way? We are using mod_jk version 1.20, and
> considering updating it.
>
> In the logs, there's no hint of trouble until a string of exceptions
> like the following occurs. The actual select statement varies.
>
> 2009-09-22 14:39:46,417  WARN TP-Processor620
> org.hibernate.util.JDBCExceptionReporter - SQL Error: 0, SQLState:
> null
> 2009-09-22 14:39:46,418 ERROR TP-Processor620
> org.hibernate.util.JDBCExceptionReporter - Cannot get a connection,
> pool error Timeout waiting for idle object
> 2009-09-22 14:39:47,052  WARN TP-Processor895
> org.sakaiproject.db.impl.BasicSqlService - Sql.dbRead: sql: select
> AX.SESSION_ID,AX.SESSION_SERVER,AX.SESSION_USER,AX.SESSION_IP,AX.SESSION_HOSTNAME,AX.SESSION_USER_AGENT,AX.SESSION_START,AX.SESSION_END,AX.SESSION_ACTIVE
> from   SAKAI_SESSION AX inner join SAKAI_PRESENCE A ON AX.SESSION_ID =
> A.SESSION_ID where A.LOCATION_ID = ? 200930-1545-LIT-030-01-presence
> org.apache.commons.dbcp.SQLNestedException: Cannot get a connection,
> pool error Timeout waiting for idle object
>    at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:104)
>
>
> Joshua Swink
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