Re: Freeing logical logs

tolly brumbelow (tolly.brumbelow@bridge.bst.bls.com) wrote: : I don't know what version of informix you are using but if it is 7.1x : Informix does not actually free a logical log until it is ready to : reuse it. Once the log has been used it will never show free again : just the UB status. Once it is time to reuse the log it will reuse : it. You should have no problem unless the next log in the order : also contains the last checkpoint. : I was told they did this so informix tech would have some way of : recovering some data for those folks backing the logs up to /dev/null. : -- : Tolly Brumbelow, Informix DBA : email:tolly.brumbelow@bridge.bellsouth.com I believe you will find this documented in ${INFORMIXDIR}/release/SERVERS_7.1 for 7.10.UD1. There were alot of enhancements in this release. However I have discovered that the backed up logs (that don't contain an open transaction) will be freed if you drop a logical log. (Call it just another piece of worthless information.) I keep hearing more reasons why this was done including what you have listed, plus the fact that this will allow for a faster recovery if you need to restore an engine from an archive because more logs are on disk and don't need to be restored from tape. Also they are available for use by onlog for a longer period of time. I think Informix should start using the even positions in the onstat output and changing the sysmaster:syslogs table to actually show which logs are eligible to be freed, though the log itself is still used. Otherwise it's truely a pain to try to figure this stuff out. Scott Ratliff Systems Engineer CARS Information Systems Corp. scottr@carsinfo.com