Matthew Wakeling wrote:
> I have implemented the very same algorithm as in Postgres, emulating
> index pages and all.
> The java program uses as near an on-disc format as Postgres does -
> just held in memory instead of in OS cache.
Interesting. Hard to explain without a lot more detail.
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, emulati
"Kevin Grittner" writes:
> 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.
> I see the big difference as the fact that the Java implementation is
> dealing with everything already set up in RAM, versus n
Matthew Wakeling wrote:
> On Fri, 17 Jul 2009, Kevin Grittner wrote:
>> but a factor of 100?
> The Java code runs all in RAM, versus Postgres running all from OS
> cache or Postgres shared buffer (bit hard to tell which of those
> two it is - there is no hard drive activity anyway). The Jav
On Fri, 17 Jul 2009, Kevin Grittner wrote:
I've seen the code in Java outperform the same code in optimized C,
because the "just in time" compiler can generate native code optimized
for the actual code paths being taken rather than a compile-time guess
at that, but a factor of 100? Something els
Matthew Wakeling wrote:
> I have implemented the very same algorithm in both a Postgres GiST
> extension and as a standalone Java program. In general, the
> standalone Java program performs about 100 times faster than
> Postgres when running a large index-based nested loop join.
>
> I profiled
Peter Eisentraut writes:
>> Does anyone have any ideas/opinions/statistics on what the performance
>> difference is between the two calling conventions?
> Version 1 is technically slower if you count the number of instructions,
That would be true if you compare version-0-to-version-0 calls (ie,
On Fri, 17 Jul 2009, Peter Eisentraut wrote:
On Friday 17 July 2009 16:40:40 Matthew Wakeling wrote:
I'm considering rewriting a postgres extension (GiST index bioseg) to make
it use version 1 calling conventions rather than version 0.
Does anyone have any ideas/opinions/statistics on what the
On Friday 17 July 2009 16:40:40 Matthew Wakeling wrote:
> I'm considering rewriting a postgres extension (GiST index bioseg) to make
> it use version 1 calling conventions rather than version 0.
>
> Does anyone have any ideas/opinions/statistics on what the performance
> difference is between the t
I'm considering rewriting a postgres extension (GiST index bioseg) to make
it use version 1 calling conventions rather than version 0.
Does anyone have any ideas/opinions/statistics on what the performance
difference is between the two calling conventions?
Matthew
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