[opencms-dev] opencms6 - postgresql8 and performance

[Andreas Haumer]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Hi!

Alexander Kandzior schrieb:
| Hi Sylvie,
|
| please keep in mind that the PostgreSQL support has been contributed to the
| distribution (the initial version was developed by Antonio Core). The driver
| has been reported to work well, but I am not sure about the performance.
|
| Should there be any optimizations, such as the additional indexes you
| mention, please contribute these back to the OpenCms community so that we
| can include these improvements in a futire distribution.
|
I also found the performance of OpenCMS less optimal than
expected, especially in offline mode and/or FlexCache disabled,
and did some tests comparing MySQL and PostgreSQL database backends.

What I found does suggest that it is not the database itself
which slows things down, but rather the way OpenCMS does
access the database: With both databases I got quite similar
performance results, with a variation of perhaps 10-20% (i.e.
well within measurement precision)

Depending on the amout of objects stored in the VFS, OpenCMS
executes _lots_ of exactly the same queries several times in
a row or at least in a very short time. All those queries
are handled both by MySQL and PostgreSQL in a few milliseconds
each, but the amout of queries slows things down quite
noticeable. This was the reason for my mail to this list about a
month ago (Subject: "Caching at the OpenCMS persistence layer?",
Message ID: 42FE05A2.6090902 at xss.co.at) but alas I never got
a reply.

IMHO there is nothing the RDBMS can really do about this, it's
the application (persistence layer) which should do caching of
query results for some time or something like that. IMHO this
would speed up things much more than fine tuning at the RDMBS
Are there any plans to implement such a cache?

Comments?

- - andreas

- --
Andreas Haumer                     | mailto:andreas at xss.co.at
*x Software + Systeme              | http://www.xss.co.at/
Karmarschgasse 51/2/20             | Tel: +43-1-6060114-0
A-1100 Vienna, Austria             | Fax: +43-1-6060114-71
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.2 (GNU/Linux)
Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org

iD8DBQFDJ9lxxJmyeGcXPhERAsNUAJ0TQz2NvtiXaHiA4AGk2M5VTEc/kQCePAXi
x5aVGRKVYBwsA9h1FodDXeM=
=5INH
-----END PGP SIGNATURE-----