Very high load when 100+ concurrent users

After I migrated from Horde2 to HWE1.0.3, the webmail became

Wed, 07 Nov 2007 03:13:23 -0500

After I migrated from Horde2 to HWE1.0.3, the webmail became deadly slow - even on better HW and OS! That's why I did a research of the code and optimized one of key SQL queris so that it now works ~40 times faster with PostgreSQL. It's been tested by thousands of our users in production environment of my University for two weeks without negative feedback. The point of the enclosed patch is to replace a LEFT JOIN with inner SELECT. I was wondering if you made it that way because of some compatibility issues? I am aware that the patch may not be considered up to your coding standards, but for me it works. If possible, please merge the code as soon as possible so that next security patches won't break the hack for me :-) Sincerely, Lumir Jasiok, Ivan Dolezal

That's nice, but doesn't work for all databases that we supp

Wed, 07 Nov 2007 04:28:33 -0500

That's nice, but doesn't work for all databases that we support.

> That's nice, but doesn't work for all databases that we su

Wed, 07 Nov 2007 04:43:52 -0500

> That's nice, but doesn't work for all databases that we support. With all respect, can I ask you, which database do you mean? Even SQLite have inner select. MySQL < 4.1 is no longer supported afaik.

We support it. And Oracle, MSDE, Sybase, SQL Server, etc.

Wed, 07 Nov 2007 06:23:35 -0500

*We* support it. And Oracle, MSDE, Sybase, SQL Server, etc. Beside that we already improved the DataTree perfomance in HEAD in a more portable way.

> We support it. And Oracle, MSDE, Sybase, SQL Server, etc

Wed, 07 Nov 2007 07:27:31 -0500

> *We* support it. And Oracle, MSDE, Sybase, SQL Server, etc. Beside > that we already improved the DataTree perfomance in HEAD in a more > portable way. OK. And should you at least write on your Performance page tip, that this little patch improve performance in case that you have SQL which have inner SELECT supported? I think, that this could help a lot. We had load at server 25+ with 100 concurrent users (because of one wrong SQL command!)and now we have load under 0.7 with 150 concurrent users. That's a difference.

Well, this particular patch won't break things, but it also

Fri, 09 Nov 2007 23:10:34 -0500

Well, this particular patch won't break things, but it also won't help anyone but postgres users because of the regex match. That regex is a bit confusing to me - what are you checking for exactly? Why not use a subselect if it's supported (assuming we can tell - don't worry about that for now) and otherwise the other query? And can you please take a look at: http://cvs.horde.org/framework/DataTree/DataTree/sql.php to see the latest SQL, and perhaps update your patch for it? Thanks!