Re: Deleting overlays from cn=config

[Howard Chu <hyc@symas.com>]

Ralf Haferkamp wrote:
> Hi,
>
> as back-config does currently not have support for the delete operation
> (config_back_delete() just returns  LDAP_UNWILLING_TO_PERFORM
> currently) I am trying to figure out what is needed to get at
> least delete support for simple overlays (e.g. ppolicy or memberof)
> running.

Very brave of you. ;)

> What I am currently doing is:
> - renumber the indexes of the siblings of the overlay that's going to be
> deleted
> - remove the CfEntryInfo of the overlay from the internal config tree
> - remove the Entry from the underlying LDIF database
>
> Additionally I need to remove the overlay's slap_overinst structure from
> the overlay list of the backend and in case it was the last overlay,
> restore the original BackendInfo structure and delete the
> SLAP_DBFLAG_GLOBAL_OVERLAY flag from the BackendDB structure of the
> underlying database (for global overlays). Currently I use the
> overlay_destroy_one() function for this task. This also calls the
> db_destroy() hook of the overlay which should take are of free
> resources held by the overlay.
>
> I am a bit unsure about the db_destroy() part. Is that enough or is it
> needed to call the db_close() hooks (when provided by the overlay)
> before calling db_destroy()? Did I miss something else? Is anybody else
> currently working on this?

You should call the db_close() hook first.

> Up to now I am testing this only with some simpler overlays (memberof,
> pcache), I assume that deleting overlays that instantiate their own
> databases (like pcache, translucent(?)) might get a little more hairy.

Right. We need to distinguish between tearing down due to a normal shutdown, 
which should leave underlying data intact, and tearing down due to removal...
--
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/