Re: Transaction logging

Richard Thomas wrote: > > OK, here's a quick one. A quick look at the Databases option from > the main menu of tbmonitor shows that neither of the databases on > our system uses logging (I didn't set the system up!!). BUT, we have > had problems with the logical logs filling up due to a long > transaction (message file entries like 'Aborting Long Transaction'), > and the logical logs grow during normal OLTP operation, when no > changes are being made to the structure of the databases. If > transaction logging is currently off, how come the logical logs are > so 'active'. > > If I've completely misunderstood something, please be gentle ;-) Richard, my son, this is one of great mysteries of the universe, though somewhat more comprehensible than the question of why Coca Cola changed their formula. ;-) Think of sysmaster as a logged database. (This has been true since OnLine 4.0 but it was never an addressable database.) Even if your current database is not logged, every time you add an extent to your table, (temp or regular) the event is logged. Thus, if you have a big sort that uses a multitude of temp tables, or a correlated subquery that builds & tears down temp tables like Taz on a rampage, each such event is logged, as if the insert/delete row in sysmaster:sysextents and systabnames (and other related tables) are all being logged. No, they are not logged as entries to these sysmaster tables; they are logged as records named something like BLDCL and CHALLOC and ERASE log records. I recall a feature request by AT&T to NOT log the create/extend/delete operations in a correlated subquery. I don't know if was ever implemented but the idea sounds .. well, unsound. Gentle enough? ;-) -- -- Jake (In pursuit of undomesticated aquatic avians) +----------------------------------------------------------+ |Aside from that, how did you enjoy the play, Mrs. Lincoln?| +----------------------------------------------------------+