Optimizing performance v7

Publication server configuration options are available to optimize the performance of multi-master replication systems.

Almost all publication server performance-related configuration options for single-master replication systems apply to multi-master replication systems (except when they are database-product specific, such as for Oracle).

Set the publication server configuration options in the publication server configuration file. See Publication and subscription server configuration options for a detailed explanation of how to set the configuration options in this file.

In addition, for configuration options that apply specifically to publication databases configured with the log-based method of synchronization replication, see Log-based method of synchronization options.

The following are some other configuration options that apply only to multi-master replication systems.

uniquenessConflictDetection

The uniquenessConflictDetection option determines whether to detect uniqueness conflict at data load time or when data is applied against a target primary node. Possible values are EAGER and LAZY. Set it to EAGER if there is a high probability of duplicate inserts across primary nodes.

When the number of primary nodes is equal to two, then the conflict detection is performed in the default LAZY mode.

When the number of primary nodes is greater than two, then the conflict detection is always performed in EAGER mode. (A LAZY mode setting is ignored.) This is primarily required to avoid removing the already replicated conflicted changes from a target node, which otherwise is an expensive option.

uniquenessConflictDetection={EAGER | LAZY}

The default value is LAZY when the number of primary nodes is two.

skipConflictDetection

The skipConflictDetection option controls whether to skip conflict detection during synchronization replication. The default is false. Change this value only when the chance of data conflict across primary nodes is zero. For example, if each primary node operates on an independent set of data, then turning on this option improves the replication time.

skipConflictDetection={true | false}

The default value is false.

deadlockRetryCount

This option applies in a multi-master replication system if a deadlock is detected on a target primary node. The deadlockRetryCount option controls the number of times the publication server attempts to retry applying the changes in the current replication cycle after waiting for the number of milliseconds specified by deadlockWaitTime. Set deadlockRetryCount to 0 to turn off this option. When this option is off, the failed changes are tried in the next replication cycle.

deadlockRetryCount=n

The default value for n is 1.

deadlockWaitTime

Use the deadlockWaitTime option with the deadlockRetryCount option to set the wait time before the publication server attempts to retry applying the changes on the target primary node. Specify a value in milliseconds.

deadlockRetryCount=n`

The default value for n is 1000.