Le 3/15/12 10:33 AM, Alex Karasulu a écrit :
On Wed, Mar 14, 2012 at 6:17 PM, Emmanuel Lécharny<[email protected]>wrote:
Le 3/14/12 5:08 PM, Alex Karasulu a écrit :
On Wed, Mar 14, 2012 at 4:51 PM,<[email protected]> wrote:
Hi, when searching for a user having this objectclass hierarchy
top
|_person
|_organizationalPerson
|_inetOrgPerson
and uid = 'jsmith'
Which query would be less expensive or better/faster? Thanks!
(&
(objectclass=inetOrgPerson)
(uid=jsmith)
)
This would be faster and more efficient since the evaluation is on a
more
specific objectClass which reduces the search space from the get go.
To understand this you need to know about how the optimizer works with
scan
counts that are returned. LDAP search filters are expanded out into an AST
(abstract syntax tree) with the leaves of the tree being assertions the
branch nodes being operators. Then the optimizer annotates this AST with
scan counts, which basically is asking each index, "Hey how many results
would you return for this assertion?" So the more specific inetOrgPerson
is
more likely to return a smaller scan count.
Now if you have an index on uid then the scan count on this will be 1
since
UID should be unique (our DSA does not enforce this tho)
Uh ?
The DSA does NOT enforce UID uniqueness so this is may be a problem if your
application or organization does not enforce this was my point.
So to clarify : UID uniqueness is an OS concept, not a LDAP one.
--
Regards,
Cordialement,
Emmanuel Lécharny
www.iktek.com
