[Xapian-discuss] FLAG_WILDCARD, add_database and performance

[Olly Betts]

On Mon, Aug 04, 2008 at 09:45:47AM +0200, Oliver Flimm wrote:
> On Mon, Aug 04, 2008 at 08:57:30AM +0200, Oliver Flimm wrote:
> > > Could you profile to find where the time is spent?  Some tips are here:
> > > 
> > > http://trac.xapian.org/wiki/ProfilingXapian
> 
> it looks like some routines in libc get called alot when using a
> wildcard search.

Hmm, yes.  Can you install the package libc6-dbg and repeat?  That
should then give us actual function names in libc.

> 141 databases - 206 seconds
> 104 databases - 86 seconds
> 69 databases - 16 seconds
> 41 databases - 4 seconds
> 8 databases - 0.29 seconds

Yeah, that's looking like there's something O(n*n) or worse.

Cheers,
    Olly