Importing netbsd cdb

[Atte Peltomaki]

On Tue, Nov 05, 2013 at 11:02:26PM +0100, Jeremie Le Hen wrote:
> On Mon, Oct 28, 2013 at 12:26:28AM +0100, Baptiste Daroussin wrote:
> > 
> > Here is a code that imports the cdbrw from netbsd into a new lib/libcdbrw
> > library, the read part is also added to libc but not exposed.
> > 
> > As an example of using that library I also got the service_mkdb patches from
> > netbsd that makes it by default emit a cdb database and add a switch to allow it
> > to still create the old .db database format.
> > 
> > in the libc, getservent has been modified to first try to read the .cdb files
> > and fallback on reading the old .db file. (I'm not sure if it is worth keeping
> > reading the old db format.)
> > 
> > http://people.freebsd.org/~bapt/cdbrw.diff
> > 
> > The plan after that is to get pw_util(3) directly generating a cdb file for
> > pwd.db and spwd.db and modifiy pwd_mkdb(8) so that by default it uses the API
> > from pw_util(3) and have a switch to fallback on creating in bdb format.
> > 
> > I also plan to do the same for cap_mkdb(1) and getcap(3).
> > 
> > With cdb querying is way faster (I don't have number but I can get some it
> > needed)
> > the size of the db is also way smaller:
> >  64K   /var/db/services.cdb
> >  2,1M    /var/db/services.db
> > 
> > Any objection?
> 
> What are the benefits of this, beside generating a much smaller
> database?  Do you know about benchmarks that compare it against the
> current database engine used?  It would be unfortunate to notice a
> regression afterward :).

At least randomly googled third-party benchmarks suggest that CDB is
vastly superior to BDB:
http://www.dmo.ca/blog/benchmarking-hash-databases-on-large-data/

-- 
Atte Peltomäki
     atte.peltomaki at iki.fi <> http://kameli.org
"Your effort to remain what you are is what limits you"