From: rakesh kumar <trakeshkumar@gmail.com>
To: pgsql-performance@postgresql.org
Subject: Fwd: start up cost estimate
Date: Sun, 19 Nov 2006 09:35:08 +0530
Message-ID: <9851130611182005l6cd70e1q7c3a9459fec90f9b@mail.gmail.com> (raw)
In-Reply-To: <9851130611182001l32efca71u291fb19092b184@mail.gmail.com>
References: <9851130611180133y3ca36219td95b555ac8f2ee71@mail.gmail.com>
<38242de90611180627s76262418j1fb73bac61d30e3f@mail.gmail.com>
<9851130611182001l32efca71u291fb19092b184@mail.gmail.com>
---------- 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, Joshua Marsh <icub3d@gmail.com> wrote:
>
> 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
> > .
> >
>
> 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?
>
>
>
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To: pgsql-performance@postgresql.org
Cc: trakeshkumar@gmail.com
Subject: Re: Fwd: start up cost estimate
In-Reply-To: <9851130611182005l6cd70e1q7c3a9459fec90f9b@mail.gmail.com>
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