tdb performance

[Andrew Bartlett]

Michael Still wrote:
> 
> On Wed, 23 Jan 2002, Michael Still wrote:
> 
> Hey all, I think the original point of my question about this got lost in
> the licensing debate...
> 
> > I have been using it for one of my own open source projects (in the next
> > release), and have a few questions...
> >
> >  - is it ok for me to release tdb in my own codebase as a convenience
> >    library (libtdb?)? Are there any plans to do this for Samba anyway
> >    which I might conflict with?
> 
> This is not a license question -- my code is GPL. It is common politeness.
> Does anyone object to me distributing a snapshot of tdb in my own code? Do
> they object if I install this as libtdb? Does samba have any plans for
> this as a separate library that I might conflict with?

Snapshotting seems to be the traditional method.  It think the idea is
that tdb is sufficiently small that keeping it statically linked is not
too large a burden.  I know its just in the 'tdb' subdir of Samba HEAD,
Samba 2.2 and Samba TNG.  

> >  - I have developed some basic docbook SGML man pages for the tdb calls
> >    I feel I understand well enough, would you like a copy of them?
> >
> > And finally, the big ugly question...
> 
> The offer of the docbook sgml for man pages on the tdb calls (most of
> them) is still open.

I think this is an offer that will be taken up, but you will have to
find somebody who works on tdb (I don't).

> > tdb is not as fast as I would like it to be. I was wondering if anyone had
> > considered caching for the recently accessed keys in the database (perhaps
> > the size of the cache being configurable on open)? My hope is that perhaps
> > someone who understands the code a bit better can explain to me why it is
> > a grossly terrrible idea before I go ahead and try to implement it.
> 
> The only comment that I have had here is that the caching would need to be
> able to deal with multiple readers / writers. Does anyone have a feel
> about any other issues I should be aware of?

A memory mapped file is not sufficiently cached?  By doing it this way
the underlying OS should have slight chance of getting it cached.

Andrew Bartlett

-- 
Andrew Bartlett                                 abartlet at pcug.org.au
Manager, Authentication Subsystems, Samba Team  abartlet at samba.org
Student Network Administrator, Hawker College   abartlet at hawkerc.net
http://samba.org     http://build.samba.org     http://hawkerc.net