| From: | Matthew Wakeling <matthew(at)flymine(dot)org> |
|---|---|
| To: | Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov> |
| Cc: | Peter Eisentraut <peter_e(at)gmx(dot)net>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Calling conventions |
| Date: | 2009-07-21 13:50:01 |
| Message-ID: | alpine.DEB.2.00.0907211446070.19493@aragorn.flymine.org |
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| Thread: | |
| Lists: | pgsql-performance |
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.
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