[Xapian-discuss] xapian performance

[Olly Betts]

On Thu, Nov 16, 2006 at 10:26:58PM +0100, Arjen van der Meijden wrote:
> If you'd like a look at the results, let me know. And of course, if 
> you'd like me to try other patches and/or use AND as default operator, 
> please, also let me know.

Arjen sent me some oprofile results (off list as they were enormous!)
These showed that even in these heavy I/O cases we spend nearly 5%
of our time unpacking position lists.  I've tweaked one particular line
in that code to run 183 times faster, though the overall speed-up won't
be that impressive of course:

http://www.oligarchy.co.uk/xapian/patches/flint_fls_optimisation.patch

Percentage-wise, the speedup from this will actually be greater for
normal phrase searches rather than the extreme bad cases.

This will speed up indexing a little, but the overall effect there will
be much smaller.

Cheers,
    Olly