Re: Do selects fill logical logs?

This is a multi-part message in MIME format. --------------4E6416911723 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit 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? If the query in question needs to generate a temporary table for some reason (such as using a scroll cursor, doing a sort or group by), the space allocation for the temporary table is likely to be logged. If the temp table in question is large, the number of space allocation requests (CHALLOCs, in log nomenclature) can be high. Easiest way to find this out is to run tblog against a log that you know was filling as a result of the query. Note the predominant record type in that log. If it is CHALLOC records, then you know it is caused by temp tables. I know in DSA (i.e. 7.X) you can create a special temp dbspace that will not have allocation in it logged. I don't remember if we added that back in 5.X or not - I tend to think not. As to where it would be documented, I'd guess that it probably isn't documented. -- Dave Kosenko, Informix Professional Services **************************************************************** While it is true that there is more than one way to skin a cat, the cat himself generally fails to appreciate the differences. --------------4E6416911723 Content-Type: text/plain; charset=us-ascii; name="Ifxdiscl.txt" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="Ifxdiscl.txt" ************************************************************************* Note: please do not send me email asking about features, or asking about Informix problems and how to solve them. I answer what questions I can in this forum (comp.databases.informix) when I have the time to spare. For questions on features, call your local sales rep or check out the Informix web site (http://www.informix.com). For technical problems, call Informix tech support. ************************************************************************* Disclaimer: All opinions expressed in this message are well-reasoned and insightful; needless to say, they are not those of Informix Software, its partners or lackeys. Anyone who says otherwise is itching for a fight. --------------4E6416911723--