ldb patch

Andrew Bartlett abartlet at samba.org
Mon Apr 30 04:34:02 MDT 2012

On Mon, 2012-04-30 at 00:26 -0700, Matthieu Patou wrote:
> Hello Simo,
> Any objection with this patch ?
> The idea is to use this function in samldb modules when comparing 
> attributes name instead of using just strcmp. Comparing first the string 
> length should speed up the comparison in most cases.


I have two concerns, from different directions:
 - first, ldb_val_cmp, if implemented, should not use strcmp or
strncmp().  struct ldb_val is a data/length tuple, and may contain
embedded nul (\0) bytes.  memcmp is the only suitable comparator.

 - I also think it is premature optimisation.  A strcmp, and a memcmp
will return non-zero at the first different byte.  Additionally, I have
looked at what is 'hot' in our ldb code, and it is schema lookups,
particularly from the resolve_oid module, not samldb.  The transaction
costs (fsync()) would overwealm anything else in samldb. 

Finally, for use in samldb, which is Samba code, why not just use

Andrew Bartlett

Andrew Bartlett                                http://samba.org/~abartlet/
Authentication Developer, Samba Team           http://samba.org

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