Re: 4 join methods?

From: Sam Roberts <rabbit_at_emirates.net.ae>
Date: Sat, 02 Jun 2001 12:13:16 -0700
Message-ID: <F001.00319496.20010602120019@fatcity.com>

I did have to RTFM -
 
A cluster join is nothing more than a nested loops join involving two tables that are stored together in a cluster. Because each row from the dept table is stored in the same data blocks as the matching rows in the emp table, Oracle can access matching rows most efficiently
 
Sam
<BLOCKQUOTE
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• Original Message -----
  <DIV
  style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From:
  <A href="mailto:vgorbounov_at_simplyengineering.com"
  title=vgorbounov_at_simplyengineering.com>Vadim Gorbounov
  To: <A href="mailto:ORACLE-L_at_fatcity.com"
  title=ORACLE-L_at_fatcity.com>Multiple recipients of list ORACLE-L
  Sent: Friday, June 01, 2001 6:25 PM
  Subject: RE: 4 join methods?
  
  

Hi,
DBAs,
RTFM is so
boring, but... There is cut&paste from
<FONT
face="Times New Roman" size=3>"Oracle8i Designing and Tuning for
Performance"
   The
Optimizer
<SPAN
class=369392313-01062001>     Optimizing
joins
<SPAN
class=369392313-01062001> 





Join
Operations  

To join each pair of row sources,
Oracle must perform one of these operations:

<A
href="http://technet.oracle.com/docs/products/oracle8i/doc_library/817_doc/server.817/a76992/optimops.htm#36280"><FONT
face=Courier>Nested Loops (NL) Join<FONT
face=Courier>

<A
href="http://technet.oracle.com/docs/products/oracle8i/doc_library/817_doc/server.817/a76992/optimops.htm#36312"><FONT
face=Courier>Sort-Merge Join<FONT
face=Courier>

<A
href="http://technet.oracle.com/docs/products/oracle8i/doc_library/817_doc/server.817/a76992/optimops.htm#36362"><FONT
face=Courier>Hash Join<FONT
face=Courier> (not available with the RBO)

<A
href="http://technet.oracle.com/docs/products/oracle8i/doc_library/817_doc/server.817/a76992/optimops.htm#36428"><FONT
face=Courier>Cluster Join<FONT
face=Courier>

<FONT face=Courier
size=2>Cheers,
Vadim
Gorbounov
Oracle DBA

Received on Sat Jun 02 2001 - 14:13:16 CDT