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#1 (**permalink**) 04-19-2008, 08:45 AM

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 .

#2 (**permalink**) 04-19-2008, 08:45 AM

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?

#3 (**permalink**) 04-19-2008, 08:45 AM

"rakesh kumar" <trakeshkumar@gmail.com> writes:
> I wanted to know , how the start up cost is computed in postgresql

Look into
http://developer.postgresql.org/cvsw...ath/costsize.c

regards, tom lane

---------------------------(end of broadcast)---------------------------
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#4 (**permalink**) 04-19-2008, 08:46 AM

---------- 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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