Re: ONLINE v.4 logical logs problems

Stephen Walmsley <sjw@nb5r16.new.ox.ac.uk> wrote: :We're running Informix-Online v.4. The database is about 7 gigs and :consists of several hundred tables, many of which are >1m rows and one :which is >13m rows. Realy version 4.???? with 7G of data (of the engine, not only the tools)? :Whenever I try to drop or create an index on a large loaded table the :engine completely screws up because it creates a transaction for the :process and fills up the logical logs. If you create these indexes with a create index statement you might want to turn loging off while doint it. At least in later versions that can be done quiqly by setting your backup tape drive temporarily to /dev/null if you don't need the backup (you may not want to do that exactly because of the possible need for a backup newer than the last you made). : When they inevitably become full, :it doesn't back out of the transaction, like you might think it should, :instead it falls over and asks for a backup to be carried out to clear the :logical logs. Trouble is, it can't do the backup because the engine has :stopped dead. :Whenever this has happened I've had to recreate the entire system from :backups. It has happened when I've done a query which Informix has thought :it can speed up by creating a temporary index. This of course can't be avoided by turning off loging for the whole database. On newer engines it isn't a problem because these temporary indexes will be generated in a temporary dbspace if you set up that, and not loged. (This is an assumption from me, as I haven't realy tested this.) :Any of you have experience with this problem? When it next happens, is :there anything I can do without having to restore from tapes, which takes :about 5 hours? I don't know much about 4.x OnLine, but there will have to be some parameters to set the high water marks for the logical logs like there is in the 5.x/7.x versions. In that case the query will be stoped early enough that there is enough space in the logs to do a rollback. You should probably also increase the size of your logical logs so the rollback doesn't happen at all. : Upgrading is something I'd like to avoid as I've been told :that there are worse bugs with the later versions. There are "bugs" in what you have been told. Although there have been some versions with too many bugs (7.10.xx is one) the newer releases are generally of high quality. You shold of course upgrade. If you have (or can buy) a machine that can handle version 7.21 that (or possibly 7.13 if someone think the 7.2x versions are too early yet) is what you should get. If you have an old machine (relatively slow single CPU, limited memory) you might be better off with the latest version 5.x. There are many new features and facilities in the 7.x versions (particularly 7.21 with the OnBar backup system and other nice things) that you should be able to utilize effectively. Of course you will also want to follow the developements of the Universal Server comming out in a few days, and possibly upgrade to that after some time. :TIA, :Stephen Nils.Myklebust@idg.no NM Data AS, P.O.Box 9090 Gronland, N-0133 Oslo, Norway My opinions are those of my company The Informix FAQ is at http://www.iiug.org