X-Received: by 10.66.51.33 with SMTP id h1mr6153122pao.30.1384174410627; Mon, 11 Nov 2013 04:53:30 -0800 (PST) X-Received: by 10.183.1.40 with SMTP id bd8mr52627obd.11.1384174410400; Mon, 11 Nov 2013 04:53:30 -0800 (PST) Path: news.cambrium.nl!textnews.cambrium.nl!feeder3.cambriumusenet.nl!feed.tweaknews.nl!212.6.121.138.MISMATCH!newsfeeder.ewetel.de!newsfeed0.kamp.net!newsfeed.kamp.net!news.glorb.com!y3no6489380pbx.0!news-out.google.com!9ni19861qaf.0!nntp.google.com!i2no20593784qav.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.databases.theory Date: Mon, 11 Nov 2013 04:53:30 -0800 (PST) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=94.132.181.12; posting-account=TFP6QgoAAAA73titAzGp0JGwWI3LIZ_H NNTP-Posting-Host: 94.132.181.12 References: <96157010-f9eb-414a-a3b7-2b86ef34573b@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <959f2f3b-19a1-4cdb-8eac-af53cd89468d@googlegroups.com> Subject: Re: Query cost From: jemanuelcabral@gmail.com Injection-Date: Mon, 11 Nov 2013 12:53:30 +0000 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Xref: news.cambrium.nl On Monday, November 11, 2013 12:40:01 PM UTC, Alexander Langer wrote: > Am 08.11.2013 16:33, schrieb : >=20 > > Divison is not a primitive operation; It is implemented using a equival= ent RA expression >=20 > > =CE=A0R=E2=88=92S((=CE=A0R=E2=88=92S(r)=C3=97s)=E2=88=92=CE=A0R=E2=88= =92S,S(r)) >=20 >=20 >=20 > Explain the operator =CE=A0 - is it projection ? >=20 >=20 >=20 > In general it depends on implementation of the operations. >=20 > You know the big O Notation ? yes it is projection (sorry about the font!) I just wanted a simple approach; like for join br+br*bs using block nested = loop join (b=3Dnumber of blocks) Does it use sort merge or hash functions cause there is set difference?