On Mon, 20 Jul 2009, Kevin Grittner wrote:
Oh, well, if you load all the data into Java's heap and are accessing it through HashMap or similar, I guess a factor of 100 is about right.
No, that's not what I'm doing. Like I said, I have implemented the very same algorithm as in Postgres, emulating index pages and all. A HashMap would be unable to answer the query I am executing, but if it could it would obviously be very much faster.
I see the big difference as the fact that the Java implementation is dealing with everything already set up in RAM, versus needing to deal with a "disk image" format, even if it is cached.
The java program uses as near an on-disc format as Postgres does - just held in memory instead of in OS cache.
Matthew -- Okay, I'm weird! But I'm saving up to be eccentric. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
