Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id 4B1501337999 for ; Mon, 11 Apr 2011 20:22:37 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024) with ESMTP id 53478-06 for ; Mon, 11 Apr 2011 23:22:30 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from web38603.mail.mud.yahoo.com (web38603.mail.mud.yahoo.com [209.191.125.64]) by mail.postgresql.org (Postfix) with SMTP id D41E0133616B for ; Mon, 11 Apr 2011 20:22:28 -0300 (ADT) Received: (qmail 84765 invoked by uid 60001); 11 Apr 2011 23:22:28 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1302564148; bh=ATq15SxNdFNT9d+zcg1ygyUy59xtiGjqgJlbUV0ab7Y=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=bNMtNKI4GbPAnHc/70bM3HMkudEdChsWZ83sCJukBessLVKUN+cWcDAC3B3LLSv8Hn2B67FcZIBCcb0uATbMQLIVSCCOCUYFfr8q5qLKxm/rY7aLK3l+TWyZ9ZhlYWIi/dWPtH87PmS+njfS341ytnNV7XCuJwpBThYCyqWjAwI= DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=LVuXvmNtEIOeFJ1F3jfX5ohVWXHjrQg9X7i/HYL0rsJC5onSsni/uODcVckVy0TSnHgXvWB3rewOLiJ+RdfORipl78qINQYqUMzrkl6Ec68IUqCbckQ4dfx6E+ZbJ95BfU8JlvqMsXC4Sgzr13xBucQKIEmKq0D5Q2Aywfjt0qA=; Message-ID: <52482.84679.qm@web38603.mail.mud.yahoo.com> X-YMail-OSG: 9nMCRCQVM1mGBl1hpawAz7ek1tBAs.QaHLCf4URYYeoUQj8 pGE_H607r__1FTgyPv.Tc4RYelTq6EE5Kp9UoTc3o76JmnVZGthloeNls_9i YSKBQh9e54wL3elfJcTjQu2DEmBgXkqRdvSPiokYxt8rNZ.KDdhJNG_rQt13 d11gWv3wnD0PA9mm4xUQUNdrZNFz7yoQpbgkbKCuZeyCO7YELl.nT0YLMOuv vFktZGNb4YIqyZHqzkGfaqjzBlwYY.aBf1L7sEDVnVAywp5sTU9jvorFkUhq xgqja.fKn2fyY8313xqVEgmFBfAna_6zIoOZVFv8wbnuovskmXIAzHJWRO6y HRCvs6Miahelki1UjpSXnSLFUfqIla7zTx4ROO8xODBUrtntRNMIioD_0MV8 qUuuGwSRDfcReWA-- Received: from [41.239.68.191] by web38603.mail.mud.yahoo.com via HTTP; Mon, 11 Apr 2011 16:22:27 PDT X-Mailer: YahooMailRC/559 YahooMailWebService/0.8.109.295617 References: <64088.55807.qm@web38604.mail.mud.yahoo.com> Date: Mon, 11 Apr 2011 16:22:27 -0700 (PDT) From: Radhya sahal Subject: Re: how explain works to Mr Nathan Boley To: Nathan Boley , pgsql-performance group In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-1614682479-1302564147=:84679" X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-0.354 tagged_above=-10 required=5 tests=BAYES_00=-1.9, FREEMAIL_ENVFROM_END_DIGIT=1.553, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, RFC_ABUSE_POST=0.001, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201104/131 X-Sequence-Number: 43193 --0-1614682479-1302564147=:84679 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Thanks Mr Nathan Boley ,=0Ai want these equations to solve thsese equtions = of parameters and total time=A0 in =0Aorder to get each paramter formula=0A= i need=A0these formula=A0 in my experiments is very important to know the r= ate for =0Aeach parameter in=A0total cost for plan.=A0=0ABest =0ARadhya..= =0A=0A________________________________=0AFrom: Nathan Boley =0ATo: Radhya sahal =0ACc: pgsql-performance gro= up =0ASent: Mon, April 11, 2011 4:09:07 P= M=0ASubject: Re: [PERFORM] how explain works=0A=0A> how explian works as ma= th equations to estimate=A0cost with=A0 constatn query=0A> parameters=0A> s= uch as cpu_tuple cost ,random page cost ...etc=0A> =A0i want maths=A0 expre= ssion=A0 in order to know how these parameters will=A0effect=0A> in cost ??= ?=0A=0AThe expressions are complicated, and they are certainly not linear a= s=0Ayou seem to think from your previous post.=0A=0A> please any one can he= lp me ??=0A=0AWhat do you need this for? If your goal is to optimize a real= =0Aapplication, then you should just vary the cost parameters and measure= =0Athe resulting change in query times. If your interests are academic,=0At= here were some excellent suggestions for places to start in response=0Ato y= our previous post.=0A=0ABest,=0ANathan=0A --0-1614682479-1302564147=:84679 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Thanks Mr Nathan Bo= ley ,
=0A
i want these = equations to solve thsese equtions of parameters and total time  in or= der to get each paramter formula
=0A
i need these formula  in my experiments is very impo= rtant to know the rate for each parameter in total cost for plan. = ;
Best
=0A
Radhya..
= =0A
=0A
=0A
=0AFrom: Nathan Boley <npboley@gmail.co= m>
To: Radhya sahal &= lt;rad_cs_2006@yahoo.com>
Cc: pgsql-performance group <pgsql-performance@postgresql.org>Sent: Mon, April 11, 2011= 4:09:07 PM
Subject: Re:= [PERFORM] how explain works

> how explian works as math e= quations to estimate cost with  constatn query
> parameters=
> such as cpu_tuple cost ,random page cost ...etc
>  i wa= nt maths  expression  in order to know how these parameters will&= nbsp;effect
> in cost ???

The expressions are complicated, and= they are certainly not linear as
you seem to think from your previous p= ost.

> please any one can help me ??

What do you need this for? If your goal is to optimize a real
application, then you= should just vary the cost parameters and measure
the resulting change i= n query times. If your interests are academic,
there were some excellent= suggestions for places to start in response
to your previous post.
<= BR>Best,
Nathan
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