On Thu, Feb 15, 2001 at 05:50:45PM -0500, marc lindahl wrote:
I don't think single threaded necessarily means slower... Perhaps the performance problem lies elsewhere.
pygresqlda sequentializes queries. Period. In fact, threaded-ness has little effect on overall _total_ speed. But, a threaded solution can be very useful where there is a large range of queries running, i.e. some of which require only a short time to execute and some of which require a long time to execute. In a threaded environment, the short running tasks can steal time from the long running tasks. In a single threaded model, once a long running task starts, everyone else is blocked until the big task terminates. This gives a pyschological impression of poor performance, because the ones who are doing small units of work are blocked for arbitrary amounts of times by the hogs on the system. That said, you have two choices, stay with the simpler pygresqlda and make it harder to launch horrible queries. Or install ZPoPyDa and PoPy, which DO thread. (pychopg (sp?) is a new da just released, search freshmeat, also mutithreaded.). Again, using a threaded DA favors short running queries at the expense of long running queries. Single threaded DA favor long running queries at the expense of short running queries. Choose your poison.
From: Hannu Krosing <hannu@tm.ee> Date: Fri, 16 Feb 2001 00:30:18 +0200 To: felipe.alvarez@qlsoft.cl Cc: zope@zope.org, Hung Jung Lu <hungjunglu@hotmail.com> Subject: Re: [Zope] Zope + Postgresql = poor performance
Felipe Alvarez Harnecker wrote:
Hi Zopistas,
I'm having extremely poor performance with
zope 2.1.6 postgresql 7.0.2 pygresqlda 0.3rjr2
actualy zope create just one connection to postgres, so when postgres is executing one query all the rest are queued. Just image the mess
So, can one tell me where to look at ?
You are probably running zope single-threaded - this may happen if you start zope up from pcgi ( or just say so in your zope start file)
------------ Hannu
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