Re: Performance improvement proposal. Removal of toLowerCase calls.

Jeremy.

I am even wondering why we would be doing that and even worse using a
locale to do it.

AFAICT, the db would return everything in lower case anyway, and if the
column really had mixed case it should be returned with it's original case
intact.

Dave

Dave Cramer

dave.cramer(at)credativ(dot)ca
http://www.credativ.ca

On Thu, Jan 16, 2014 at 10:44 AM, Jeremy Whiting <jwhiting(at)redhat(dot)com>wrote:

> Hi,
> I would like to propose an optimization to improve performance in the
> jdbc driver. The performance improvement has been tested on commodity
> hardware using an industry standard Java benchmark. The overall
> benchmark metric reports an improvement in performance. Profiling using
> sampling showed calls reduced from 1100 to 0 when the benchmark workload
> is running.
>
> The optimization will eliminate calls to the method
> toLowerCase(java.util.Locale). This in the pg-jdbc
>
> org.postgresql.jdbc2.AbstractJdbc2ResultSet.findColumnIndex(java.lang.String)
> method when setting up the column index registry.
>
> For the optimization to be enabled I suggest relying on a new system
> property. Making the existing functionality the default behaviour to
> ensure existing applications do not break when the driver is upgraded.
>
> The change removes the call toLowerCase when putting items in the
> registry [1]. Essentially what's being proposed is removing sanitizing
> the key names. For best performance application code should pass SQL to
> the driver with column names already folded to lower case. But upper
> case names will still be matched in the second lookup [2] in the method.
> For this optimization to work this feature introduces a requirement on
> applications. To use all lower or upper case column names.
>
> Are there other factors that might affect this optimization that need
> to be taken into consideration ?
>
> Regards,
> Jeremy Whiting
>
> Senior Software Engineer
> Red Hat
>
> [1]
>
> https://github.com/pgjdbc/pgjdbc/blob/REL9_3_STABLE/org/postgresql/jdbc2/AbstractJdbc2ResultSet.java?#L2742
> [2]
>
> https://github.com/pgjdbc/pgjdbc/blob/REL9_3_STABLE/org/postgresql/jdbc2/AbstractJdbc2ResultSet.java?#L2752
>
>
>
> --
> Sent via pgsql-jdbc mailing list (pgsql-jdbc(at)postgresql(dot)org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-jdbc
>