Re: Subject: Confused about logical logs

J. Dority wrote: > > In article <3247F406.1291@gbar.com> Scott Dunbar <scott@gbar.com> writes: > >Subject: Confused about logical logs > >From: Scott Dunbar <scott@gbar.com> > >Date: Tue, 24 Sep 1996 09:45:26 -0500 > > >I'm confused. I am using 7.20.UC2 under Solaris 2.5. I have > >the server set up to replicate to another 7.20.UC2 dataserver. The > >confusion I have is that the logical logs stay in "U-B----" mode all > >the time. All but one of them shows 100% full. If I do a "onmode -l" > >it kicks over to another log just fine. If I do it 5 times, I have > >5 logs that have a couple of pages in use, all in the "U-B----" mode. > >None of my logs are free. One of them is in "U---C-L" mode, as I > >would expect. > > As of 7.11.UC1, Informix no longer changes that status to "F" (free). The > reason for the change is so that you can use onlog to analyze logs > (even if they've been freed). onlog doesn't work on logs that have > been marked with an "F", so by not marking them, it makes onlog > more useful ( I guess.....) This is documented in the release notes. > > Even if your logs are really free, its not as easy to figure this out. > You can use onstat -x and look for the smallest beg log number -- this > tells you the earliest log that has an active transaction and from this > you can tell which logs have active transactions spanning them. > There are some sysmaster queries that can provide this information > as well.... > > I wish they would change it back!! onstat -l is used much more > frequently than onlog. > > > My LTAPEDEV is /dev/null. Everything seems to work the way > >it is supposed to except for oncockpit, but it doesn't like > >replication anyhow. Is this a problem? Why are none of the logs > >ever being freed? There are no long transactions (indeed, I've > >bounced the dataserver a couple of times and there's nobody even > >connected). > > > Any info would be greatly appreciated. Thanks in advance. Hi, When LTAPEDEV is set /dev/null, even though you have not explicitly backed up the logical logs (using either ontape -a or ontape -c), Informix will always put the flag "U-B", making that log reusable. The only time you will not be able use that log would be if the last checkpoint is still in some previous log. As long as you have "U---C-L", any log with "U-B" can be reused. I cannot really gather from your posting whether you have Data Replication turned on or not. If you do, logical logs are critical to preserve the DR. My advise would be back them to a tape or disk. And ofcourse it is always a good idea to do Level 0 archive. Hope this will help Zakeer Shaik