Обсуждение: IMPORTANT:migration de mysql =>postgresql
BOnjour, Je dois améliorer les temps de réponses de requete d'une base de donnée, notament celles qui permettent de générer un rapport. Cette base de données est actuellement sous mysql. SI je fais une migration vers postgresql mes temps de réponse seront-ils réellement améliorés? Sachant que quand je crée un rapport j'ai entre 100 et 600 requetes Merci pour toute réponses de vos part. Hugo rousse
At 6/19/2003 16:32, hugo_rousse@club-internet.fr wrote: >BOnjour, Hello >Je dois améliorer les temps de réponses de requete d'une base de donnée, >notament celles qui permettent de générer un rapport. >Cette base de données est actuellement sous mysql. >SI je fais une migration vers postgresql mes temps de réponse seront-ils >réellement améliorés? >Sachant que quand je crée un rapport j'ai entre 100 et 600 requetes > >Merci pour toute réponses de vos part. > >Hugo rousse I'm really not sure about this, but I do belive basic netiquette requires you to write messages in the one language shared between all (most) of IT people, and that's English. Cheers, >---------------------------(end of broadcast)--------------------------- >TIP 5: Have you checked our extensive FAQ? > > http://www.postgresql.org/docs/faqs/FAQ.html -- Radu-Adrian Popescu CSA, DBA, Developer Aldratech Ltd.
At 6/19/2003 16:32, hugo_rousse@club-internet.fr wrote: >BOnjour, > >Je dois améliorer les temps de réponses de requete d'une base de donnée, >notament celles qui permettent de générer un rapport. >Cette base de données est actuellement sous mysql. Basically you don't _need_ to move to postgresql only because a report is running slowly. You can do from horrible to divine database design with anything from mysql to oracle. :-) The reasons for moving to postgresql are far more complex that bad performing queries, as those queries can be cached, rewritten, combined, tweaked, tables re-normalized and so on. Reasons for moving to postgresql are things such as ACID compliance, stored procedures, better scalability under heavy load, and standing out from the crowd :^) >SI je fais une migration vers postgresql mes temps de réponse seront-ils >réellement améliorés? MySQL is rumoured to be somewhat faster than PostgreSQL on "single-user, a lot of reads" scenarious. >Sachant que quand je crée un rapport j'ai entre 100 et 600 requetes That sounds a bit strange; you mean the report comprises between 100 and 600 requests to the database ? Queries ? Then perhaps you should look into some other way of doing this, like query re-writing and combining, using an external program (say a perl script) that connects thru an unix socket (probably faster that tcp/ip, if that's the case), .... it depends. If those are rows, on the other hand, something is _really_ wrong. >Merci pour toute réponses de vos part. Cheers. -- Radu-Adrian Popescu CSA, DBA, Developer Aldratech Ltd.
On Thu, 19 Jun 2003, Radu-Adrian Popescu wrote: > >Sachant que quand je crée un rapport j'ai entre 100 et 600 requetes > > That sounds a bit strange; you mean the report comprises between 100 and > 600 requests to the database ? Queries ? > Then perhaps you should look into some other way of doing this, like query > re-writing and combining, using an external program > (say a perl script) that connects thru an unix socket (probably faster that > tcp/ip, if that's the case), .... it depends. > If those are rows, on the other hand, something is _really_ wrong. He may well be doing something in MySQL that you can only do with 600 queries, that would be one big query in postgresql. That would be one of the reasons I didn't choose mysql at the beginning was I needed to do stuff that would have required way too many queries in MySQL.
At 6/19/2003 11:14, scott.marlowe wrote: >On Thu, 19 Jun 2003, Radu-Adrian Popescu wrote: > > > >Sachant que quand je crée un rapport j'ai entre 100 et 600 requetes > > > > That sounds a bit strange; you mean the report comprises between 100 and > > 600 requests to the database ? Queries ? > > Then perhaps you should look into some other way of doing this, like query > > re-writing and combining, using an external program > > (say a perl script) that connects thru an unix socket (probably faster > that > > tcp/ip, if that's the case), .... it depends. > > If those are rows, on the other hand, something is _really_ wrong. > >He may well be doing something in MySQL that you can only do with 600 >queries, that would be one big query in postgresql. That would be one of >the reasons I didn't choose mysql at the beginning was I needed to do >stuff that would have required way too many queries in MySQL. I guess that's a good point too. I hear mysql has some real problems with subqueries. (never used the damn thing for anything more than toying around, thought). But it's still pretty exagerated to think you can do 600 mysql queries in one postgresql query. My 2c sit on something being wrong in the way the whole reports is thought of and designed. Cheers, -- Radu-Adrian Popescu CSA, DBA, Developer Aldratech Ltd.
...and on Thu, Jun 19, 2003 at 08:20:08PM +0300, Radu-Adrian Popescu used the keyboard:
>
> I guess that's a good point too. I hear mysql has some real problems with
> subqueries. (never used the damn thing for anything more
> than toying around, thought).
Subqueries in MySQL are next to ENOENT, with the exception of subselects,
which _are_ ENOENT. :)
They are scheduled for 4.1, which is (as of time speaking) still marked as
alpha.
Cheers,
--
Grega Bremec
Sistemska administracija in podpora
grega.bremec-at-noviforum.si
http://najdi.si/
http://www.noviforum.si/