[imp] ldap

[Rick Stevens]

Mike Coughlan wrote:

> can you please elaborate on this with a URL or document? are you implying
> that it is buggy?
> thanks,

No, it's not buggy.  LDAP is intended to be used like your address
book.  You put entries into it once and refer to them often. You only
update it every once in a while.

Most LDAP implementations use DBM as the back end.  When you modify an
entry, the DBM back end essentially has to delete the old entry and add
the modified entry on to the end as though it was a new entry.  The
space used by the old entry isn't reclaimed, and as such, leaves a
"hole".  If you update your LDAP a lot, the DBM files grow and grow,
with a large portion of the space unused.

SQL and other databases are structured with specific storage sizes for
the elements used, so you can bugger a given entry to your heart's
content and you'll affect the same spot in the file.  LDAP attributes
don't have fixed (or maximum) sizes, so it's far less efficient in
dealing with updates.

Just remember, LDAP is like a phone book and should be treated like one.

> -----Original Message-----
> From: Rick Stevens [mailto:rstevens@publichost.com]
> Sent: Wednesday, December 06, 2000 12:37 PM
> To: imp@lists.horde.org
> Subject: Re: [imp] ldap
> 
> I'd shy away from using LDAP for session management.  LDAP isn't
> really designed to be written to a lot--it's a directory service.
> Modifying LDAP entries a lot pokes a lot of holes in the underlying
> databases and slows down access.  Use a SQL engine, DBM or something
> similar.

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