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From Scott Eade <se...@backstagetech.com.au>
Subject Re: Will migrating from 3.0 to 3.3 help me?
Date Wed, 01 Oct 2008 05:22:38 GMT
Richard Walker wrote:
> The first thing I noticed was the huge difference in performance
> using different versions of JDBC drivers.  Older versions
> (e.g., pg74.216.jdbc3.jar) work well; newer ones (e.g.,
> one I tried for PostgreSQL 8.2, postgresql-8.2-506.jdbc3.jar) don't.
> The difference is staggering - a set of queries that takes 10 seconds
> with an old driver takes over 90 seconds with a newer
> driver.
> I ran a trace on the code and found out what's going on - the Column
> class in the village library does lots of requests on metadata.
> In the old JDBC driver, these calls are not implemented;
> in the newer drivers, they are, and there are now
> 12 - yes, twelve! - extra database queries being generated
> for each original query.
> I notice a Sybase user has already reported this at:
> http://issues.apache.org/jira/browse/TORQUE-36

Given that the the queries must have been working prior to upgrading the 
the JDBC driver it would seem that the metadata is not actually needed 
for query execution.

How about you make yourself a copy of village.jar with the offending 
lines in the Column class commented out and see if your queries still 
execute correctly.  Really this would just be the opposite of having the 
stub methods in the old JDBC driver.  Provided your application is not 
accessing the metadata present in the Column class (directly or 
indirectly) this should be a valid approach.


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