- Berkeley DB Reference Guide:
- Berkeley DB Replication
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Replication Manager methods
Applications which use the Replication Manager support generally call
the following Berkeley DB methods. The general pattern is to call various
methods to configure Replication Manager, and then start it by calling
DB_ENV->repmgr_start. Once this initialization is complete, the
application rarely needs to call any of these methods. (A prime
example of an exception to this rule would be the DB_ENV->rep_sync method,
if the application is doing delayed synchronization.)
- DB_ENV->repmgr_set_local_site
- The DB_ENV->repmgr_set_local_site method configures the TCP/IP address of
the local site, by specifying the port number on which it is to listen
for incoming connection requests. This method must be called exactly
once before calling DB_ENV->repmgr_start.
- DB_ENV->repmgr_add_remote_site
- The DB_ENV->repmgr_add_remote_site method adds a remote site to the list of
sites initially known by the local site. The remote site is specified
in terms of a TCP/IP network address: host name and port number. This
method may be called as many times as necessary to configure all known
remote sites. Note that it is usually not necessary for each site in
the replication group initially to know about all other sites in the
group. Sites can discover each other dynamically, as described in
Connecting to a new site.
- DB_ENV->repmgr_set_ack_policy
- The DB_ENV->repmgr_set_ack_policy method configures the acknowledgement
policy to be used in the replication group, in other words, the
behavior of the master with respect to acknowledgements for
"permanent" messages, which implements the application's requirements
for transactional guarantees. The
current implementation requires all sites in the replication group
configure the same acknowledgement policy.
- DB_ENV->rep_set_nsites
- The DB_ENV->rep_set_nsites method tells Replication Manager the total number
of sites in the replication group. This is usually necessary for
proper operation of elections, and for counting message
acknowledgements (depending on the acknowledgement policy).
- DB_ENV->rep_set_priority
- The DB_ENV->rep_set_priority method configures the local site's priority for
the purpose of elections.
- DB_ENV->rep_set_timeout
- This method optionally configures various timeout values. Otherwise
default timeout values as specified in DB_ENV->rep_set_timeout are
used.
- DB_ENV->set_event_notify
- Once configured and started, Replication Manager does virtually all of
its work in the background, usually without the need for any direct
communication with the application. However, occasionally events
occur which the application may be interested in knowing about. The
application can request notification of these events by calling the
DB_ENV->set_event_notify method.
- DB_ENV->repmgr_start
- The DB_ENV->repmgr_start method starts the replication system. It opens the
listening TCP/IP socket and creates all the background processing
threads that will be needed.
In addition to the methods previously described, Replication Manager
applications may also call the following methods, as needed:
DB_ENV->rep_set_config, DB_ENV->rep_set_limit, DB_ENV->rep_sync,
DB_ENV->rep_stat.
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