I think, it is the difference between writing 43602 records into the file and displaying 43602 records on screen.
If you wrap up your select into select count(a.*) from your select, e.g.:
Select count(a.*) from (select ... from mytable join .. join ... order by ....) as a;
This will exclude time to display all these rows, so you'll get the same (or better) performance as with "copy" into
textfile, which will prove this theory.
Regards,
Igor Neyman
-----Original Message-----
From: pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of belal
Sent: Friday, February 06, 2015 3:31 AM
To: pgsql-performance@postgresql.org
Subject: [PERFORM] Copy command Faster than original select
I made complex select using PGAdmin III Query Editor, Postgre server 9.3
select ... from mytable join .. join ... order by ....
I get [Total query runtime: 8841 ms. 43602 rows retrieved.]
but when I use
copy ([same above select]) to '/x.txt'
I get [Query returned successfully: 43602 rows affected, 683 ms execution time.]
these test made on the same machine as the postgresql server.
can anyone explain huge difference in executing time?
best regards all
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