tdb performance

Andrew Bartlett abartlet at
Sat Jan 26 22:56:02 GMT 2002

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
Manager, Authentication Subsystems, Samba Team  abartlet at
Student Network Administrator, Hawker College   abartlet at

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