Function
Stops database replication on the slave system and converts the slave
database into a normal database.
If you specify the failover=true attribute on the master, the
attribute sends the remaining log records to the slave instance and then sends a
failover message to the slave. The replication functionality and the database
are then shut down on the master system. If failover is successful, an exception
with the error code XRE20 is thrown. Hence, when issued on the master, the
failover=true attribute does not return a valid connection.
You may specify this attribute on the slave only if the network connection
between the master and the slave is down.
When you specify this attribute on the slave, or when a failover message is
sent as part of the execution of the failover=true attribute on the
master, all transaction log chunks that have been received from the master are
written to disk. The slave replication functionality is shut down, and the boot
process of the database is allowed to complete. The database is now in a
transaction consistent state, reflecting all transactions whose commit log
records were received from the master. When issued on the slave, the
failover=true command returns a valid connection.
The Derby instance where
this command is issued must be serving the named database in replication mode.
For more information, see the topics under "Replicating databases" in the
Derby Server and Administration Guide.
Combining with other attributes
You must specify a database name in the connection URL, either in the
subprotocol or by using the databaseName=nameofDatabase
attribute.
If authentication is turned on, you must also specify
this attribute in conjunction with the user=userName and
password=userPassword
attributes. Authorization for the master database cannot be checked when the
network connection is down, so the requirement that the user must be the
database owner is not enforced.
You may not specify this attribute in conjunction with any attributes not
mentioned in this section.
Examples
-- start failover from master using database name in subprotocol,
-- authorization
jdbc:derby:myDB;failover=true;user=mary;password=little88lamb
-- start failover using databaseName attribute, no security
jdbc:derby:;databaseName=myDB;failover=true;
