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<< Replication and security | Creating a log in a non-default location >>

Logging on a separate device

<< Replication and security | Creating a log in a non-default location >>
Derby Server and Administration Guide
82
Failure Situation
Action Taken
derby.replication.logBufferSize to configure the size limit of
the buffer; see the Derby Reference Manual for details.
Slave loses connection
with master.
The slave tries to reestablish the connection with the master
by listening on the specified host and port. It will not give
up until it is explicitly requested to do so by either the
failover=true or stopSlave=true connection URL attribute.
If a failover is requested, the slave applies all received log
records and boots the database as described in
Forcing a
failover
. If the stopSlave=true attribute is specified, the slave
database is shut down without further actions.
Two different masters
of database D try to
replicate to the same
slave.
The slave will only accept the connection from the first
master attempting to connect. Note that authentication is
required to start both the slave and the master, as described
in
Replication and security
.
The master and slave
Derby instances are
not at the same Derby
version.
An exception is raised and replication does not start.
The master Derby
instance crashes, then
restarts.
Replication must be restarted, as described in
Starting and
running replication
.
The master Derby
instance is not able to
send log data to the
slave at the same pace
as the log is generated.
The main memory log
buffer gradually fills up
and eventually becomes
full.
The master notices that the main memory log buffer is filling
up. It first tries to increase the speed of the log shipment to
keep the amount of log in the buffer below the maximum.
If that is not enough to keep the buffer from getting full,
the response time of transactions may increase for as long
as log shipment has trouble keeping up with the amount
of generated log records. You can use properties to tune
both the log buffer size and the minimum and maximum
interval between consecutive log shipments. See the Derby
Reference Manual for details.
The slave Derby
instance crashes.
The master sees this as a lost connection to the slave. The
master tries to reestablish the connection until the replication
log buffer is full. Replication is then stopped on the master.
Replication must be restarted, as described in
Starting and
running replication
.
An unexpected failure is
encountered.
Replication is stopped. The other Derby instance of the
replication pair is notified of the decision if the network
connection is still alive.
Logging on a separate device
You can improve the performance of update-intensive, large databases by putting a
database's log on a separate device, which reduces I/O contention.
By default, the transaction log is in the log subdirectory of the database directory. Use
either of the following methods to store this log subdirectory in another location:
· Specify the non-default location by using the logDevice=logDirectoryPath attribute
on the database connection URL when you create the database.