From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
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To: | dale(at)icr(dot)com(dot)au |
Cc: | "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: playing with timestamp entries |
Date: | 2001-04-25 21:57:55 |
Message-ID: | 10252.988235875@sss.pgh.pa.us |
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Lists: | pgsql-general |
Dale Walker <dale(at)icr(dot)com(dot)au> writes:
> I use the 'hash' type as queries regarding usage will always be of the
> form "select ...... where username='xxx';"
Use a btree anyway. Postgres' btree implementation is much better than
its hash index implementation.
> insert into sumlog
> select s.username,
> to_char(timestamp(h.time_stamp),'YYYY-MM') as date,
> sum(h.acctsessiontime),
> sum(float8(h.acctinputoctets)/1000000),
> sum(float8(h.acctoutputoctets)/1000000)
> from subscribers as s,history as h
> where s.username=h.username
> group by s.username,date;
> This works fine, but as the database size is constantly growing the
> summary table takes a while to calculate...
What plan does EXPLAIN show for this query?
regards, tom lane
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