On Wed, Jan 15, 2014 at 4:42 PM, <rmcgi...@oceris.com> wrote: > > > Ok, running the gfix -sweep with everyone logged out did work and only > took about 5 minutes. I believe the issue came from me only trying to run > the sweep one time and a transaction being stuck. I never tried to run > sweep AFTER restarting the services. I also think there was confusion > because I was under the incorrect assumption that gbak was doing a sweep > while backing up. > Gbak (without the -g switch) will remove old record versions, but, like a sweep, it only works up to the oldest transaction that was active when the oldest transaction currently open started. So if you have a transaction that's stuck, neither gbak nor sweep will remove versions newer than some version older than the stuck transaction.
The difference between sweep and a gbak backup without the -g is that sweep resets the value of the Oldest Interesting Transaction (OIT), and gbak does not. After a sweep, all record versions older than the sweep threshold are guaranteed to be committed. That used to be important because InterBase had to carry around a bit vector the length of the difference between the OIT and the current transaction - which could be a lot of bits on a machine with a mid-1980's sized memory. Each bit in the vector represents the state of a transaction - committed or not. The vector still exists, but it takes a whole lot of bits to use any significant fraction of the memory of a modern computer. Good luck, Ann
