Ciao Leonardo,
I am not sure if this could apply to your case, but maybe - unless you
have done it before - you could look at windowing functions
(http://www.postgresql.org/docs/current/interactive/tutorial-window.html).
They require PG8.4+ though.
Cheers,
Gabriele
On Wed, 4 May 2011 11:51:08 +0100 (BST), Leonardo Francalanci
<m_lists@xxxxxxxx> wrote:
Hi,
I'm going to need to GROUP BY the same table
multiple times. That is, something like:
select (some aggregate functions here) from
tableA group by f1, f2
select (some other aggregate functions here) from
tableA group by f3, f4
etc
The table is pretty large; can someone suggest the
best way of doing it? Is running N queries at the same
time (that is, using N connections with N threads in
the client code) the only way to speed up things (so
that the "concurrent scan" thing can help)? Or it's
more likely that it won't help that much, given that
we have a fairly good storage? Just trying to get some
ideas before starting testing....
(table will be 5M rows, where some of the group by
select could return 3-400K groups)
Leonardo
--
Gabriele Bartolini - 2ndQuadrant Italia
PostgreSQL Training, Services and Support
Gabriele.Bartolini@xxxxxxxxxxxxxx - www.2ndQuadrant.it
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