---------- Forwarded message ----------
From: rakesh kumar <trakeshkumar@gmail.com>
Date: Nov 19, 2006 9:31 AM
Subject: Re: [PERFORM] start up cost estimate
To: Joshua Marsh <icub3d@gmail.com>
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, rakesh kumar < trakeshkumar@gmail.com> 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 .
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?