db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Daniel John Debrunner <...@debrunners.com>
Subject Re: Two poorly optimized functions in SQLParser.java
Date Mon, 27 Dec 2004 20:21:44 GMT
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Dain Sundstrom wrote:


> Seriously, if you believe that this is a real problem with performance,
> prove it.  This is a policy we have had in the geronimo project since
> the beginning.  There have been several times where people believed that
> certain code was slow, tried to prove it, and it turned out it was
> another chunk of code.

Another way to look at it is to say what difference would it make to
real world applications if you made this piece of code, say, ten times
faster?

Hopefully any well written JDBC application spends less than 1% of its
time compiling SQL statements. The compile phase is made up of four
stages, parse, bind, optimise and generate. Parse time is probably the
quickest stage, let's say 15% of the compile time. So if your ten times
improvement made parsing twice as fast, you will only improve overall
performance by less than 0.1%.

Traditionally performance work on Cloudscape mainly focussed on making
execution time improvements, not compile time improvements.

Dan.

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.5 (MingW32)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFB0G7YIv0S4qsbfuQRAjINAKCXGD1xnjiBHwut1cSUb4czjR/HKwCdHC9t
wAt5N7d7p8oRaOVh8s0kjeE=
=/ohv
-----END PGP SIGNATURE-----


Mime
View raw message