>> Heck, even RAM isn't 1.0. I'm also involved with the Redis project, >> which is an in-memory database. Even for a pure-RAM database, it turns >> out that just using linked lists and 100% random access is slower than >> accessing page images. > > That's a slightly different problem, though. Sequential vs. random > access is about whether fetching pages n, n+1, n+2, ... is faster than > skipping around, not whether accessing fewer pages is faster than > more.
It's not though. Redis stores stuff as lists and sets, so it actually does a lot of sequential access of data. Like if people are accessing an ordered set, they're usually pulling the whole thing. It turns out that *even in RAM* storing stuff in an ordered fashion on data "pages" is more efficient than just using pointers. -- -- Josh Berkus PostgreSQL Experts Inc. http://www.pgexperts.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers