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Re: Connection pools with LOB?

From: Oliver Jowett <oliver(at)opencloud(dot)com>
To: Ole Streicher <ole-usenet-spam(at)gmx(dot)net>
Cc: pgsql-jdbc(at)postgresql(dot)org
Subject: Re: Connection pools with LOB?
Date: 2004-02-28 23:53:53
Message-ID: 40412A11.2060608@opencloud.com (view raw or flat)
Thread:
Lists: pgsql-jdbc
Ole Streicher wrote:
> This code gives me a class cast exception when I try to get the
> LargeObjectManager; it seems that the connection is not really a PGConnection.
> 
> So, how can I access a Large Object from a connection pool?

Use a more recent driver; the 7.3 drivers are quite old and newer 
drivers are backwards-compatible. The connection casting problem was 
fixed in CVS some time ago:

$ cvs log org/postgresql/jdbc2/optional/PooledConnectionImpl.java
[...]
----------------------------
revision 1.6
date: 2003/01/14 05:46:49;  author: barry;  state: Exp;  lines: +4 -3
Patch from Aaron Mulder to have pooled connections implement PGConnection

  Modified Files:
         jdbc/org/postgresql/jdbc2/optional/PooledConnectionImpl.java
         jdbc/org/postgresql/test/jdbc2/optional/BaseDataSourceTest.java
----------------------------

Looks like this change didn't make it into the 7.3 branch (which I think 
is no longer maintained, at least for JDBC purposes).

> I use the pg73jdbc3.jar from the download page to access a Postgresql 7.3.4
> database (SuSE 9.0).
> BTW, the jdbc jars provided with the SuSE distrib and also the jdbc jars
> from the Postgresql download site seem not to contain the connection pool
> classes at all. Is this on purpose?

I can't speak for SuSE, but you are mistaken about the 
jdbc.postgresql.org drivers:

> $ ls -l pg73jdbc3.jar 
> -rw-r--r--    1 oliver   oliver     184505 Aug  8  2003 pg73jdbc3.jar
> $ jar tvf pg73jdbc3.jar | grep -i pool       
>   2164 Thu Aug 07 10:57:50 NZST 2003 org/postgresql/jdbc3/Jdbc3ConnectionPool.class
>    459 Thu Aug 07 10:57:50 NZST 2003 org/postgresql/jdbc3/Jdbc3PooledConnection.class
>   3005 Thu Aug 07 10:57:50 NZST 2003 org/postgresql/jdbc3/Jdbc3PoolingDataSource.class
>   1602 Thu Aug 07 10:57:50 NZST 2003 org/postgresql/jdbc2/optional/ConnectionPool.class
>   3338 Thu Aug 07 10:57:50 NZST 2003 org/postgresql/jdbc2/optional/PooledConnectionImpl$ConnectionHandler.class
>   4209 Thu Aug 07 10:57:50 NZST 2003 org/postgresql/jdbc2/optional/PooledConnectionImpl.class
>   1753 Thu Aug 07 10:57:50 NZST 2003 org/postgresql/jdbc2/optional/PoolingDataSource$1.class
>   7258 Thu Aug 07 10:57:50 NZST 2003 org/postgresql/jdbc2/optional/PoolingDataSource.class

-O

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Next:From: Marc G. FournierDate: 2004-02-29 02:11:49
Subject: Re: Where has the source code moved to?
Previous:From: Oliver JowettDate: 2004-02-28 23:33:38
Subject: Re: Jdbc3PoolingDataSource and Statement relationship???

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