From: | Srinivas Iyyer <srini_iyyer_bio(at)yahoo(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-novice(at)postgresql(dot)org |
Subject: | Re: Please comment on pgsql speed at handling 550,000 records |
Date: | 2006-02-07 18:36:04 |
Message-ID: | 20060207183604.41978.qmail@web34512.mail.mud.yahoo.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-novice |
Sorry Tom, for the confusion.
seq_id is not equal to go_id
seq_id = NM_000033
go_is = GO:049934
It is bad on my part I wrote
seq_id = 'xxxx'
go_id = 'xxxx' it should be 'yyyy'
srini
--- Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Srinivas Iyyer <srini_iyyer_bio(at)yahoo(dot)com> writes:
> > [ It's not fast to do 500K commands like ]
> > insert into tablec (seq_id,gos_id) values (
> > (select seq_id from table a where seq_name
> ='xxxx'),
> > (select gos_id from table b where go_id =
> 'xxxx'));
>
> Don't you want something like
>
> insert into tablec (seq_id,gos_id)
> select seq_id, gos_id from a, b where seq_name =
> go_id;
>
> SQL is not a low-level language, and breaking a
> table-wise operation
> down into bite-size parts is not the way to make it
> go fast. The
> startup overhead for a command is almost always
> going to dwarf the time
> spent processing any one row, so you want to make
> sure you process as
> many rows per command as feasible.
>
> Also, make sure you've ANALYZEd both input tables
> beforehand,
> else the planner may choose a poor plan for this
> command.
> It'd be worth looking at the EXPLAIN output for the
> command
> just to make sure nothing silly is happening.
>
> regards, tom lane
>
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
From | Date | Subject | |
---|---|---|---|
Next Message | Tom Lane | 2006-02-07 18:46:17 | Re: Please comment on pgsql speed at handling 550,000 records |
Previous Message | Srinivas Iyyer | 2006-02-07 18:33:28 | Re: Please comment on pgsql speed at handling 550,000 records |