Re: about explain analyze

Tom, I am afraid that I don't understand. My first example:
wow=# explain analyze select max(click.accesses) from click;                                                   QUERY
PLAN
-----------------------------------------------------------------------------------------------------------------
Aggregate (cost=1103.70..1103.70 rows=1 width=8) (actual 
 
time=289.391..289.393 rows=1 loops=1)   ->  Seq Scan on click  (cost=0.00..971.36 rows=52936 width=8) (actual 
time=0.013..133.943 rows=52936 loops=1) Total runtime: 289.498 ms
(3 rows)

Time: 290,695 ms

select max() returns only one row... If you mean rows in Seq Scan than
gettimeofday was called (52936+1)*2. Huge value :(



Tom Lane wrote:
> Teodor Sigaev <teodor@sigaev.ru> writes:
> 
>>How many times is gettimeofday called?
> 
> 
> Twice per plan node visit, if you are doing EXPLAIN ANALYZE.  (The
> number of "visits" is one more than the number of rows returned.)
> 
>             regards, tom lane
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 7: don't forget to increase your free space map settings

-- 
Teodor Sigaev                                  E-mail: teodor@sigaev.ru