about explain analyze - Mailing list pgsql-hackers

From Teodor Sigaev
Subject about explain analyze
Date
Msg-id 3FC606A7.90300@sigaev.ru
Whole thread Raw
Responses Re: about explain analyze
List pgsql-hackers
Hello!

Explain analyze takes 3 times more time for execution. Why?

wow=# \timing
Timing is on.
wow=# select max(click.accesses) from click;   max
---------- 10944762
(1 row)

Time: 105,654 ms
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
wow=# select version();                                                 version 

--------------------------------------------------------------------------------------------------------- PostgreSQL
7.4on i386-unknown-freebsd5.1, compiled by GCC gcc (GCC) 3.2.2 
 
[FreeBSD] 20030205 (release)
(1 row)


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



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