[389-devel] about Bug 590826 - Reloading database from ldif causes changelog to emit "data no longer matches" errors

[Rich Megginson]

The problem comes from the method we use to check if the changelog does 
not match the database in replica_check_for_data_reload().  The RUV in 
the database contains obsolete elements from replicas that are no longer 
in use.  replica_check_for_data_reload() uses ruv_covers_ruv() to see if 
all of the max csns in the database ruv are in the changelog maxruv, and 
vice versa.  It fails because the database ruv contains these obsolete 
elements not found in the changelog maxruv.

My question is - why do we care?  Isn't it sufficient to check that the 
replicageneration in the changelog is the same as the replicageneration 
in the database ruv?  The replicageneration is supposed to be the unique 
identifier of the "starting point" of the replicated data.  If the data 
is reloaded (e.g. from an ldif not created with db2ldif -r), a new 
replicageneration will be created, and the data will mismatch.

Or, alternately, leave the check for all of the ruv elements in, but 
just warn if the database contains ruv elements not in the cl maxruv 
e.g. something like
"WARNING: The database RUV contains these elements not present in the 
changelog max ruv:
....
These elements may be obsolete, in which case you should remove them.
If they are not obsolete, you should check those servers to make sure 
replication is occurring."