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@xxxxxxxxxxxxx>
To: <lawpoop@xxxxxxxxx>
Cc: <pgsql-general@xxxxxxxxxxxxxx>
Sent: Friday, July 13, 2007 3:39 AM
Subject: Re: [GENERAL] optimizing postgres
lawpoop@xxxxxxxxx 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
