On Thu, Jul 16, 2009 at 4:41 PM, Heikki Linnakangas<heikki.linnakan...@enterprisedb.com> wrote: > Rick Gigger wrote: >> If you use an rsync like algorithm for doing the base backups wouldn't >> that increase the size of the database for which it would still be >> practical to just re-sync? Couldn't you in fact sync a very large >> database if the amount of actual change in the files was a small >> percentage of the total size? > > It would certainly help to reduce the network traffic, though you'd > still have to scan all the data to see what has changed.
The fundamental problem with pushing users to start over with a new base backup is that there's no relationship between the size of the WAL and the size of the database. You can plausibly have a system with extremely high transaction rate generating WAL very quickly, but where the whole database fits in a few hundred megabytes. In that case you could be behind by only a few minutes and have it be faster to take a new base backup. Or you could have a petabyte database which is rarely updated. In which case it might be faster to apply weeks' worth of logs than to try to take a base backup. Only the sysadmin is actually going to know which makes more sense. Unless we start tieing WAL parameters to the database size or something like that. -- greg http://mit.edu/~gsstark/resume.pdf -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
