Consultor Eletrônico

Status: Verified

GOAL:

How to use the -RO parameter?

GOAL:

How does the Read-Only (-RO) parameter work?

FACT(s) (Environment):

Progress 9.x
OpenEdge 10.x
All Supported Operating Systems

FIX:

The Read-only (-RO) Client Connection parameter opens a database for read-only access. Use -RO to access a database stored on read-only media (a read-only optical disk, for example).

NOTE: Do not run servers for a read-only database. PROGRESS does not support servers for read-only users. Note also that -RO is not a database server startup parameter. -RO is a Client Connection parameter, and thus should be specified in the client connection string.

If you use the -RO parameter when other users are updating the database, you might see invalid data, such as stale data or index entries pointing to records that have been deleted. For an example of such refer to Solution P15081, "Error when connecting -RO to multi-user database"

A read-only session is essentially a single-user session. Read-only users do not share database resources (database buffers, lock table, index cursors). However, unlike a single-user database, a read-only database can be simultaneously accessed by multiple -RO users. Once a connection to the Database has been established in read-only mode, the client cannot switch back to regular mode using the same connection. The client has to disconnect and reconnect to the Database without specifying the -RO parameter.

When a read-only session starts, it does not check for the existence of a lock file for the database. Furthermore, a read-only user opens the database file, but not the log or before-image files.

Read-only user activity does not appear in the log file prior to Progress 9.1E and OpenEdge 10.0B, where changes were introduced to have -RO clients log their connection and disconnection times to the database lg file. Refer to Solution P100245, "-RO clients writing to log file"