On Fri, 11 Jun 2010, Kenneth Marshall wrote:
If you check the archives, you will see that this is not easy to do because of the effects of caching.
Indeed. If you were to take the value at completely face value, a modern hard drive is capable of transferring sequential pages somewhere between 40 and 100 times faster than random pages, depending on the drive.
However, caches tend to favour index scans much more than sequential scans, so using a value between 40 and 100 would discourage Postgres from using indexes when they are really the most appropriate option.
Matthew -- A. Top Posters > Q. What's the most annoying thing in the world? -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
