In mixed-version environments, interaction between Replication Servers of different versions is restricted to the capabilities of the oldest version. Information associated with new features may not be available to Replication Servers of earlier versions.
Features in the new version, when sent to downstream Replication Servers of earlier versions, can break the multisite availability (MSA) replication and must be filtered out. In Replication Server 15.0, mixed-version support has been enhanced to provide a mechanism in which the later-version feature data is filtered out by the primary Replication Server before sending it out to the downstream Replication Servers of earlier versions.
To enable the primary Replication Server to block certain new feature commands not supported by earlier versions of Replication Server, a new Replication Server configuration parameter, dist_stop_unsupported_cmd, is available for all server and connection-level commands.
Replication Server commands that include the new configuration parameter are described in Table 6-4.
Replication Server command |
Syntax |
|---|---|
configure replication server |
configure replication server set dist_stop_unsupported_cmd to [on | off] |
alter connection |
alter connection srv.db set dist_stop_unsupported_cmd to [on | off] |
alter logical connection |
alter logical connection lsrv.ldb set dist_stop_unsupported_cmd to [on | off] |
By default, dist_stop_unsupported_cmd is set to off. When this parameter is set to on, DIST suspends itself if a command cannot be sent to some destination Replication Servers. You have to resume the DIST by skipping the entire transaction or by resetting this parameter to off.
When the parameter is set to off, the distributor (DIST) thread skips the newer commands to earlier version Replication Servers.
