Hash Tables

Posted in 2004

Wilkinson, Marcus — Wed, 28 Jan 2004 18:36:43 -0500 — source: Usenet: comp.databases.informix

This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ------_=_NextPart_001_01C3E5F7.95E57D11 Content-Type: text/plain Hi, Could anyone explain to me exactly what happens when you perform a hash join between multiple tables. The Informix doc I have read only references a two table join. It says that a hash table is built of the driving table and matched against hash values of the second table. What happens if there is a third and fourth table? Would more than one hash table be built? How can I determine how big the hash table(s) will be and how much memory they will consume. Thanks for your help. Marcus Wilkinson ------_=_NextPart_001_01C3E5F7.95E57D11 Content-Type: text/html <html> <head> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii"> <meta name=Generator content="Microsoft Word 11 (filtered)"> <style>  </style> </head> <body lang=EN-GB link=blue vlink=purple> <div class=Section1> Hi,   Could anyone explain to me exactly what happens when you perform a hash join between multiple tables.   The Informix doc I have read only references a two table join.  It says that a hash table is built of the driving table and matched against hash values of the second table.   What happens if there is a third and fourth table?   Would more than one hash table be built?   How can I determine how big the hash table(s) will be and how much memory they will consume.   Thanks for your help.     Marcus Wilkinson   </div> </body> </html> ------_=_NextPart_001_01C3E5F7.95E57D11-- sending to informix-list sending to informix-list