On Jun 18, 2004, at 7:31 AM, Gary Cowell wrote:
> The explain output on postgres shows the same
> execution with a scan on vers and a sort but the query
> time is 78.6 seconds.
Does it run just as slow if you run it again?
It could be a case of the caches being empty
> Oracle but I think I've configured comparible
> buffering and sort area sizes, certainly there isn't
> much physical IO going on in either case.
Configuring PG like Oracle isn't the best thing in the world. The
general PG philosophy is to let the OS do all the caching & buffering
- this is reversed in the Oracle world. In 7.4 the rule of thumb is no
more than 10k shared_buffers.. beyond that the overhead of maintaining
it becomes excessive. (This isn't really the case in 7.5)
Curiously, what are your sort_mem and shared_buffers settings?
Jeff Trout <jeff(at)jefftrout(dot)com>
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