Progress Fathom Replication
User’s Guide

> ## Enhanced Read-only mode

> When the Fathom Replication agent is running, the database is placed into an Enhanced Read-only mode (ERO). ERO mode enforces user read-only functionality while providing the benefits of Fathom Replication multi-user access to a database. For information on what your product supports see the "Database access once Fathom Replication is running" section.

> When the target database is opened and the Fathom 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 Fathom Replication agent. Any process connected to a target database cannot lock records.

> Caution: For remote 4GL or SQL connections that are originated from Version 9.1C and earlier, enhanced read-only cannot properly identify an attempted record update. If a client tries to do an update to a record, it will terminate abnormally with a system error.

> ERO mode, unlike a read-only client, is a database server concept. Enhanced read-only 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 and the target database transitions to a normal Progress database, all future connections to the target database are full access. All current connections are disconnected; when they reconnect, they are full access. See the "Fathom Replication failure processing" section for more information on the target database transitioning to a normal Progress database.

Copyright © 2004 Progress Software Corporation www.progress.com Voice: (781) 280-4000 Fax: (781) 280-4095