When the OpenEdge Replication agent is running, the target database is placed into an Enhanced Read-Only mode (ERO). ERO mode enforces user read-only functionality while providing the benefits of OpenEdge Replication multi-user access to a database.
When the target database is opened and the OpenEdge Replication agent is started, ERO is implicitly set. Any process that connects to the target database cannot make database updates, with the exception of the OpenEdge Replication agent. Any process connected to a target database cannot lock records.
ERO mode, unlike client read-only functionality, is a database server concept. The mode offers full database capabilities with a buffer pool, shared buffers, and read-only private buffers. The read-only (-RO) restriction is set at the client side. ERO is a database restriction.
When a failure occurs on the source database, failover transitions the target database.
If you have a Replication Set defined, the primary target transitions to the source, and the other target becomes a target of the new source.
Without a Replication Set, one or both targets transition to a source or a normal (non-Replication-enabled) OpenEdge database, however the targets cannot synchronize with each other after the transition, and a rebase is required to reestablish replication.
At this point, all future connections to the target database(s) are full access. All current connections are disconnected; when they reconnect, they are full access. See OpenEdge Replication activity during normal processing for more information about the transitioning of a target database to a normal OpenEdge database.
If you have a Replication Set defined, the primary target transitions to the source, and the other target becomes a target of the new source.