Re: optimizing postgres
От | Zlatko Matić |
---|---|
Тема | Re: optimizing postgres |
Дата | |
Msg-id | 004e01c7c51a$02c8e3d0$89ac0fd4@zlatkovyfkpgz6 обсуждение исходный текст |
Ответ на | optimizing postgres (lawpoop@gmail.com) |
Ответы |
Re: optimizing postgres
|
Список | pgsql-general |
Hello, Tom. I don't understand relation between constraints and indexes. By using EMS PostgreSQL Manager Lite, I created indexes on columns, some of them are unique values. But when I open it in PgAdmin, all such "unique" indexes are listed as constraints and there are no indexes in Indexes section. When I open it again in EMS PostgreSQL Manager, they are listed as "Indexes". Does it mean that I need to create additional indexes on the same columns? Is "Constrain" index as well? Thanks, Zlatko ----- Original Message ----- From: "Tom Lane" <tgl@sss.pgh.pa.us> To: <lawpoop@gmail.com> Cc: <pgsql-general@postgresql.org> Sent: Friday, July 13, 2007 3:39 AM Subject: Re: [GENERAL] optimizing postgres > lawpoop@gmail.com writes: >> It turned out he was right for our current set up. When I needed to >> empty the project table to re-parse data, doing a cascading delete >> could take up to 10 minutes! > > You mean ON CASCADE DELETE foreign keys? Usually the reason that's > slow is you forgot to put an index on the referencing column. PG > doesn't force you to have such an index, but unless the referenced > table is nearly static you'll want one. > > I too am fairly suspicious of the N-tables-are-faster-than-another- > key-column mindset, but you'd need to do some actual experimentation > (with correctly optimized table definitions ;-)) to be sure. > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 9: In versions below 8.0, the planner will ignore your desire to > choose an index scan if your joining column's datatypes do not > match
В списке pgsql-general по дате отправления: