Re: Spped of max

Whoops, a litle fast on the keyboard.

This bit about:

>I mean, isn't this really equivalent to:
>
>explain select max(event_id) from (select event_id from syslog_event order
>by event_id desc limit 1) as syslog_event;
>NOTICE:  QUERY PLAN:
>
>Aggregate  (cost=0.70..0.70 rows=1 width=8)
>  ->  Subquery Scan syslog_event  (cost=0.00..0.70 rows=1 width=8)
>        ->  Limit  (cost=0.00..0.70 rows=1 width=8)
>              ->  Index Scan Backward using syslog_event_pkey on syslog_event  (cost=0.00..2435803.36 rows=3490163
width=8)
>

can obviously be shortened to:

explain select event_id from syslog_event order by event_id desc limit 1;
NOTICE:  QUERY PLAN:

Limit  (cost=0.00..0.70 rows=1 width=8)
  ->  Index Scan Backward using syslog_event_pkey on syslog_event  (cost=0.00..2435803.36 rows=3490163 width=8)

Ed



which flies as expected?  Now, this type of thing gets me real worried
about how good the optimizer really is.  I have a number of fairly
complicated queries that are created via criteria from the web, and it
would be a pain to get them all "hand-optimized" if I cannot rely on the
optimizer at least picking reasonable methods.

Miscellaneous: Using 7.2.1 under OpenBSD 3.0

Ed