Re: Sesame Native Store OPS indexing (was Re: [update] piggybank performance profiling)

From: Stefano Mazzocchi <>
Date: Tue, 13 Sep 2005 12:20:00 -0400

Vineet Sinha wrote:
> The summary
> -----------
> OPS indexing for the Sesame Native Store has been implemented. And it
> works beautifully in Relo. Stefano should be looking at it in Piggy Bank.

You rock!!

I'm on it.

> Details
> -------
> Single Modified File:

NOTE: I have moved the modified sesame store in a more prominent
location (since both relo and longwell are going to depend on it), find
it at

> The working jar file

This one is still there.

> Implementation was as Arjohn had suggested. I did not see any bugs.
> Adding statements seems to have added a 25% cost.
> Beyond adding the second comparator, I also renamed previous
> btree/file/filename variables to include 'spo' before them and made a
> copy for 'ops'. triples.dat is now triples-1.dat and triples-2.dat.
> The other issue is a Jeen mentioned, the large file size for
> transmission. The best solution could be to not require it for
> transmission and build the second index automatically (in fact this
> should also increase the add performance, relying on the spo index until
> the ops index is ready).
> There were no unit tests, but tests on Relo should have been good.
> I can send patch, after we fix any issues. Let me know if you have
> questions.
> Arjohn, thanks for your help!

NOTE: To comply with licensing restrictions, the patch is released under
the LGPL.

Stefano Mazzocchi
Research Scientist                 Digital Libraries Research Group
Massachusetts Institute of Technology            location: E25-131C
77 Massachusetts Ave                   telephone: +1 (617) 253-1096
Cambridge, MA  02139-4307              email: stefanom at mit . edu
Received on Tue Sep 13 2005 - 16:15:35 EDT

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