Re: Accessing database statistics

o yes i forgot u could try to see

EXPLAIN select count(*) from <table>;

but i still think tom is u'r best bet for this.

Ok, this all depends on how postgresql does this query. If it (behind
the scenes) does a call to a system table which holds a field for the
count of each table then fine - nice and efficient. However if this does
a scan of the appropriate table and counts the number of tuples then
returns this figure, then this is a really expensive operation, and I
need this to be fast.

Tony

Duncan Adams (DNS) wrote:

>for the first part u might try
>
>select count(*) from <table>;
>
>-----Original Message-----
>From: Tony Griffiths(RA) [mailto:griffitt(at)cs(dot)man(dot)ac(dot)uk]
>Sent: Thursday, May 30, 2002 2:01 PM
>To: pgsql-novice(at)postgresql(dot)org
>Subject: [NOVICE] Accessing database statistics
>
>
>Hi,
>I need to write a query that returns the number of rows currently stored
>in a table. I presume that I issue a query against the system tables,
>but don't know which one(s) to do this against. So a couple of questions:
>
>1) With specific reference to my problem, how do I do this?
>2) More generally, is there any where that gives detailed descriptions
>of the system tables?
>
>Many thanks,
>
>
>Tony
>
>
>---------------------------(end of broadcast)---------------------------
>TIP 6: Have you searched our list archives?
>
>http://archives.postgresql.org
>