On Wed, Feb 4, 2015 at 1:05 PM, Josh Berkus <j...@agliodbs.com> wrote: > Let me push "max_wal_size" and "min_wal_size" again as our new parameter > names, because: > > * does what it says on the tin > * new user friendly > * encourages people to express it in MB, not segments > * very different from the old name, so people will know it works differently
That's not bad. If we added a hard WAL limit in a future release, how would that fit into this naming scheme? >> We are too often far too conservative about these things. If we make >> the default 192MB, it will only ever get tuned in one direction: up. >> It is not a bad thing for us to set the settings high enough that once >> in a great while someone might find them to be too high rather than >> too low. >> >> I find it amazing that anyone here thinks that a user would be OK with >> using 192MB of space for WAL, but 384MB would break the bank. The >> hard drive in my laptop is 456GB. The point is, with Heikki's work >> here, you're only going to use the maximum amount of space if you have >> massive write activity. And if you have massive write activity, it's >> extremely likely that you will be OK with using a very modest amount >> of disk space to have that be fast. Right now, we have to be really >> conservative because we're going to use the full allocation all the >> time, but this fixes that. I think. > > Hmmm, I see your point. I spend a lot of time on AWS and in > container-world, where disk space is a lot more constrained. However, > it probably makes more sense to recommend non-default settings for that > environment, since it requires non-default settings anyway. > > So, 384MB? That's certainly better, but I think we should go further. Again, you're not committed to using this space all the time, and if you are using it you must have a lot of write activity, which means you are not running on a tin can and a string. If you have a little tiny database, say 100MB, running on a little-tiny Amazon instance, handling a small number of transactions, you're going to stay close to wal_min_size anyway. Right? -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
