N-way replication "dn_callback : entries have identical CSN"

[Adrien Futschik <adrien.futschik@atosorigin.com>]

Hy !

I am still working on n-way multi master replication. I am using 
refreshAndPersist mode with to masters.

My first test was to inject in parallel 2 x 500 entries to the first master and 
also 2 x 500 entries to the second master. 

The goal is to see how the replication behaves when massive adds are performed 
to both masters.

When I used OpenLDAP 2.4.11, I suffered lost. The 1000 entries where 
successfully added on each master, but a few entries where lost in the 
replication process. I didn't found any "errors" in the log, even with debug 
on.
The only suspect messages I had, where like this :
=> bdb_idl_insert_key: c_put id failed: DB_LOCK_DEADLOCK: Locker killed to 
resolve a deadlock (-30995)
=> bdb_dn2id_add 0x543: parent (ou=clients,o=edf,c=fr) insert failed: -30995 

I then switched to OpenLDAP 2.4.14 and did not have the problem anymore (same 
configuration). I guess this was a bug form 2.4.11.

Still, I had a few of theses messages in the log : 
conn=9 op=1 => bdb_dn2id_add 
dn="cn=M2client2@laposte.net,ou=clients,o=edf,c=fr" ID=0xb: put failed: 
DB_LOCK_DEADLOCK: Locker killed to resolve a deadlock -30995

but I also got a few of theses :
dn_callback : entries have identical CSN 
cn=M2client20@laposte.net,ou=clients,o=edf,c=fr 
20090217155418.854085Z#000000#002#000000
syncrepl_entry: rid=004 be_search (0)
syncrepl_entry: rid=004 cn=M2client20@laposte.net,ou=clients,o=edf,c=fr
syncrepl_entry: rid=004 entry unchanged, ignored 
(cn=M2client20@laposte.net,ou=clients,o=edf,c=fr)
do_syncrep2: cookie=rid=004,sid=002
syncrepl_entry: rid=004 LDAP_RES_SEARCH_ENTRY(LDAP_SYNC_ADD)

Can anyone explain to me why ? is this normal ? 
The dn_callback message comes from the master log-file where 
"cn=M2client20@laposte.net,ou=clients,o=edf,c=fr" was inserted.

Thanks in advance,

Adrien Futschik