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From Alex Karasulu <>
Subject Re: Should modifications made on cn=schema stored on disk ?
Date Fri, 14 Jan 2011 11:45:43 GMT
On Fri, Jan 14, 2011 at 1:22 PM, Emmanuel Lecharny <> wrote:
> Hi,
> I was wrong : the modifications done on cn=schema are persisted in
> ou=schema.
> It's a bit dirty, but when we update the schemaManager, we also call an
> internal operation that updates the schema partition.
> What puzzled me is that in this case, the changelog is activated only for
> the first operation (there is a strange method called isFirstOperation()
> which is used to know if we should store the entry in the backend or not).
> I'm still investigating the whole stuff...

Everyone please see my last email which should shed light on why all
the schema subsystem was designed the way it was. Just to summarize:

Registries: The In Memory Runtime Representation
Used for fast lookups and to quickly render CN=schema
Loaded from OU=schema
Maintained in sync with OU... persistant store when changes are made there.

CN=schema: The schema subentry, aka subschemaSubentry
A facade to comply with LDAP protocols way to expose schema.
Inefficient representation to operationally manage schema constraints.
A virtual entry constructed on the fly reflecting the contents of the
Operations against entry translated into operations against OU... format.

OU=schema: Internal Persistant Parameterize Schema Store
The persistent store for schema information.
Schema data from here is loaded into the registries.
Parameterizes schema entity fields to facilitate consistency management.
Changes here, automatically update registries.


Alex Karasulu
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