---------- Forwarded message ----------
From: rakesh kumar <[EMAIL PROTECTED]>
Date: Nov 19, 2006 9:31 AM
Subject: Re: [PERFORM] start up cost estimate
To: Joshua Marsh <[EMAIL PROTECTED]>
Hi
for suppose if I had a
query , something like :
select o_orderpriority
from orders
where o_totalprice < 156163 and exists
( select *
from lineitem
where l_orderkey = o_orderkey
and l_extendedprice < 38570
)
what is the amount of cost of EXISTS SUBQUERY involved in estimate of
totalcost .
where l_orderkey is part of index of lineitem , and o_orderkey is primary
key of orders table.
Thanks .
On 11/18/06, Joshua Marsh <[EMAIL PROTECTED]> wrote:
On 11/18/06, rakesh kumar < [EMAIL PROTECTED]> wrote:
>
> Hi ,
> I wanted to know , how the start up cost is computed in
> postgresql . can u give me an example to illustrate the estimation of start
> up cost .
> thanku raa
> .
>
It would be very helpful to have a lot more information. Some questions
that come to mind:
Approximately how many records will you be storing?
How big do you think your biggest tables will be?
How frequently will your biggest tables be accessed (x/day, x/second,
x/week)?
Will those accesses be read only, or read/write?
How important is availability vs. cost?
Who is your favorite Irish folk singer?
