Re: about explain analyze

On Fri, 28 Nov 2003, Tom Lane wrote:

> "Marc G. Fournier" <scrappy(at)postgresql(dot)org> writes:
> > Actually, I'm noticing similar "problems" with v7.4 ... "EXPLAIN ANALYZE"
> > seems to be showing some *very* high ms for execution time, but if you run
> > the actual query, it doesn't seem to take even 1/10th the time reported
> > ...
>
> Example? I don't see anything out of line here.

pgsql74# /usr/local/pgsql/bin/psql -U pgsql -c "SELECT count(rec_id) FROM url" 186_archives
count
--------
209872
(1 row)

pgsql74# /usr/local/pgsql/bin/psql -U pgsql -c "EXPLAIN ANALYZE SELECT max(rec_id) FROM url" 186_archives
QUERY PLAN
--------------------------------------------------------------------------------------------------------------------
Aggregate (cost=11177.19..11177.19 rows=1 width=4) (actual time=2400.579..2400.585 rows=1 loops=1)
-> Seq Scan on url (cost=0.00..10741.55 rows=174255 width=4) (actual time=0.056..1387.803 rows=209872 loops=1)
Total runtime: 2407.095 ms
(3 rows)

pgsql74# time /usr/local/pgsql/bin/psql -U pgsql -c "SELECT max(rec_id) FROM url" 186_archives
max
--------
690582
(1 row)

0.000u 0.004s 0:00.32 0.0% 0+0k 0+0io 0pf+0w

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