RE: Do selects fill logical logs?

__________________________________________ Russell P. Kahler russell@oncontact.com (414)375-6540 W67 N250A Evergreen Blvd. Cedarburg, Wi 53012 ___________________________________________ }---------- }From: Kahler, Russell P. }Sent: Tuesday, July 30, 1996 1:19 PM }To: 'John Prideaux' }Subject: RE: Do selects fill logical logs? } }Actually I first ran into this problem under 7.12 online. What }informix did with 7.12 is they added what they call temp dbspaces. }these temp dbspaces are not logged at all. So what you do is setup }these temp dbspaces and use them for temp. storage. This is the only }way I know of getting around logging these tables. } }Russ.. } __________________________________________ } } Russell P. Kahler russell@oncontact.com } (414)375-6540 } W67 N250A Evergreen Blvd. } Cedarburg, Wi 53012 } ___________________________________________ } }---------- }From: John Prideaux[SMTP:alastl@ix.netcom.com] }Sent: Tuesday, July 30, 1996 11:21 AM }To: informix-list@rmy.emory.edu }Subject: Re: Do selects fill logical logs? } }Andrew, }I am not sure where this is documented, but the facts as I understand }them are: } }When a subquery is processed, a temp table is created and dropped for }each }row in the main query. By default, temp tables are created with }logging, }so correlated subqueries generate large logs. While you can CREATE }TEMP ... }WITH NO LOG and you can SELECT ... INTO TEMP WITH NO LOG, I know of no }way }to turn off logging for a correlated subquery. This would be a very }useful }(and probably not very difficult, assuming the engine architecture is }reasonably sane) feature. Anyone at Informix listening? } }Andrew Cilia wrote: }> }> I am currently investigating an incident on a 5.03 ONLINE }> engine where a select statement with a correlated subquery }> seems to populate the logical logs. Reputable sources tell }> me that this is standard procedure on complicated queries. }> Can anyone confirm this? Where is it documented? }> Precisely under what conditions are logs used by queries. }> Why does it need to be this way? }> } }-- }------------------------------------------------------------------------ }-------John Prideaux e-mail: alastl@ix.netcom.com Phone: }(217)839-2121 }Aladdin Steel, Inc. Fax: }(217)839-4327 }------------------------------------------------------------------------ }------- } }