Peter, Check out pg_fincore. Still kind of risky on a production server, but does an excellent job of measuring page access on Linux. ----- Original Message ----- > Baron Swartz's recent post [1] on working set size got me to > thinking. > I'm well aware of how I can tell when my database's working set > exceeds available memory (cache hit rate plummets, performance > collapses), but it's less clear how I could predict when this might > occur. > > Baron's proposed method for defining working set size is interesting. > Quoth: > > > Quantifying the working set size is probably best done as a > > percentile over time. > > We can define the 1-hour 99th percentile working set size as the > > portion of the data > > to which 99% of the accesses are made over an hour, for example. > > I'm not sure whether it would be possible to calculate that today in > Postgres. Does anyone have any advice? > > Best regards, > Peter > > [1]: > http://www.fusionio.com/blog/will-fusionio-make-my-database-faster-percona-guest-blog/ > > -- > Peter van Hardenberg > San Francisco, California > "Everything was beautiful, and nothing hurt." -- Kurt Vonnegut > > -- > Sent via pgsql-performance mailing list > (pgsql-performance@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-performance > -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
