Is there a system of cache in pgsql 7.3rc1 ?
Is there a system of cache in pgsql 7.3rc1 ?
От:
David Pradier <dpradier@apartia.fr>
Дата:
Hi! This is my first post to the list. I'm currently searching to improve the performances of some requests, and recently switched to postgresql 7.3rc1. I thought there would be in this release a kind of cache for the results of requests (i.e. the second time a request is asked, if the concerned tables haven't changed, the result of the request isn't calculated another time, but taken from a cache.) ? Am i wrong ? Does such a mechanism exist ? Is it planned to create one ? Thanks for your help. Best regards, David -- dpradier@apartia.fr
Re: Is there a system of cache in pgsql 7.3rc1 ?
От:
"scott.marlowe" <scott.marlowe@ihs.com>
Дата:
On Thu, 21 Nov 2002, David Pradier wrote: > Hi! > This is my first post to the list. > > I'm currently searching to improve the performances of some requests, > and recently switched to postgresql 7.3rc1. > > I thought there would be in this release a kind of cache for the results > of requests (i.e. the second time a request is asked, if the concerned > tables haven't changed, the result of the request isn't calculated another time, but > taken from a cache.) ? > Am i wrong ? > Does such a mechanism exist ? > Is it planned to create one ? This issue has been discussed. The performance gains from a results cache are not all that great, and postgresql's mvcc "locking" mechanism isn't a good candidate to be served by results caching / updating. Generally speaking, if you've got enough memory in your box, then the results are "cached" in memory, requiring only sorting before being output. This is a niche problem that is not likely to be implemented any time soon.
