Re: logical logs

In article 1659@das13.snide.com, dave@das13.snide.com (Dave Snyder) writes: >In article <8727@emory.mathcs.emory.edu>, ilg@dasher.cc.bellcore.com (guthrie,ian) writes: >> I am running informix-online 4.00.UH2 on a Pyramid MIS-12/05 (OSx 5.1a). >> Part of the output from 'tbstat -l' is listed below: >> address number flags uniqid begin size used %used >> e0068944 1 U---C-L 5 100d64 250 66 26.40 >> e0068960 2 F------ 0 100e5e 250 0 0.00 >> e006897c 3 U-B---- 3 100f58 250 250 100.00 >> e0068998 4 U-B---- 4 101052 250 250 100.00 >> [deleted] >> 2. Why would online not release a log that has been backed-up (the >> last two lines)? >One reason that comes to mind is that you have a long-transaction that has >spanned the first two logs and is now writing to the third. That's most often the reason. Sometimes, though, tbinit daemon just hasn't gotten around to adjusting the flag yet! > >> 3. Is there a way to force online to release backed-up logs? >> >Not during a long-transaction. If a transaction spans logs, the logs >can't be freed until the transaction is terminated. The reason for this >is for a ROLLBACK WORK. If the logs are freed, how is Online going to >rollback the transaction? Now this is neat... if you have a long >transaction that enters the last log, Online will automatically rollback >the work. What happens if you don't have enough space in the last log >to rollback the transaction... you'd better have a real recent archive of >your data. With more recent releases of OnLine (4.1 and 5.0), you have much more flexi- bility in determining *when*, because of LTX conditions, a transaction gets rolled back. You can, for example, set threshholds as percentages of total log space rather than letting the determination of whether you have an LTX be decided by how many logs you have. > >DAS >-- >David A. Snyder @ Snide Inc. - Folcroft, PA Current Release > is db4glgen-3.4 >UUCP: ..!uunet!das13!dave INTERNET: dave.snyder@snide.com -- jerry pope