MDB_BAD_VALSIZE error

[Chris Card <ctcard@hotmail.com>]

Hi All,

I'm running openldap 2.4.36 on centos 6.3, 64 bit.

I'm finally trying out MDB as a replacement for BDB in our openldap setup, and I've noticed that I'm getting MDB_BAD_VALSIZE errors when adding some DNs, which could be added without error when using BDB as the backend: 

52e9170b <= mdb_dn2id_add 0x5da55e: -30781
52e9170b mdb_add: dn2id_add failed: MDB_BAD_VALSIZE: Too big key/data, key is empty, or wrong DUPFIXED size (-30781)

Looking at the code, it seems that this error happens when MDB_MAXKEYSIZE is exceeded and MDB_MAXKEYSIZE is set to 511 as far as I can see.

The DNs which are giving this error are between 232 and 255 characters long.

Does the MDB backend have an implicit limit on the length of valid DNs? 
Can this be increased (by changing MDB_MAXKEYSIZE) and if so, what is the longest DN which can be supported by the MDB backend?

Chris