[Xapian-discuss] Search performance issues and profiling/debugging search?

[Olly Betts]

On Wed, Oct 24, 2007 at 02:49:05PM +0200, Ron Kass wrote:
> http://www.pidgintech.com/other/fts/test/valgrind_2-4-6-7-8-9-10.txt

Well, this does indicate a location where uninitialised data is used,
but I can't see where that's coming from.  Everything I've tried works
fine for me under valgrind.

What compiler are you using here?  If it's Intel's C++, you should
upgrade to valgrind 3.2.3 since that includes a fix which may be
relevant (the reported location is FP code):

  n-i-bz   fix false uninit-value errs in icc9 generated FP code

Otherwise, I wonder if compiler optimisation is confusing the issue and
causing valgrind to misreport the exact location.

Can you rebuild xapian-core without optimisation and rerun under
valgrind?

To rebuild unpack a fresh xapian-core source tree and configure it like
so:

./configure CXXFLAGS='-O0 -g' <any other configure options>

Then "make" and "make install" as usual.

Please keep this source tree around as I'll probably need to get you to
try more things.

> http://www.pidgintech.com/other/fts/test/valgrind-full_2-4-6-7-8-9-10.txt

The memory leaks here are all Perl not Xapian (I suspect they aren't
genuine leaks but just the result of not wasting effort releasing memory
which will all be released to the OS when Perl exits).

This report does show another uninitialised access but it looks like it
is probably a knock-on effect of the first, so let's investigate that
first.

Also, are you using Enquire::set_weighting_scheme()?

Cheers,
    Olly