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SQL Anywhere 11.0.1 » SQL Remote » SQL Remote Deployment and Administration » SQL Remote Administration » Understanding the Message Agent (dbremote)


Choosing the Message Agent (dbremote) mode

The Message Agent (dbremote) can be run in one of two modes:

  • Continuous mode   In continuous mode, the Message Agent (dbremote) periodically sends messages, at times specified by the send frequency properties of each remote user. When it is not sending messages, it receives messages as they arrive.

    Continuous mode is useful at consolidated databases, where messages may be coming in and going out at any time, to spread out the workload and to ensure prompt replication.

    See Run the Message Agent (dbremote) in continuous mode.

  • Batch mode   In batch mode, the Message Agent (dbremote) receives and processes incoming messages, scans the transaction log once, creates and sends the outgoing messages, and then stops.

    Batch mode is useful at occasionally-connected remote databases, where messages can only be exchanged with the consolidated database when a connection is made, for example, when the remote database dials up to the main network.

    See Run the Message Agent (dbremote) in batch mode.

Message Agent (dbremote) requirements

SQL Remote is very flexible. Within a system, you can run the Message Agent (dbremote) in both modes, on multiple devices, and on multiple operating systems. However, SQL Remote has the following requirements:

  • REMOTE DBA authority or DBA authority required   The Message Agent (dbremote) must be run by a user with REMOTE DBA authority or DBA authority. See Grant REMOTE DBA authority.

  • The maximum message length must be the same for each Message Agent (dbremote) in the system   This length can be restricted by operating system memory allocation limits. Received messages that are longer than the limit are deleted as corrupt messages. The default value is 50000 bytes. This length is configurable, using the Message Agent (dbremote) -l option. See Message Agent (dbremote).