Timesten - Replication (High Availability, Workload distribution)

About

TimesTen replication enables to achieve:

  • (near-continuous|High) availability
  • or workload distribution

by replicating transactions between IMDB TimesTen databases.

Type of replication

  • Asynchronous
  • Synchronous Serial
  • Synchronous Parallel

Architecture

A master host is configured to send updates and a subscriber host is configured to receive them.

A host can be both a master and a subscriber in a bidirectional replication scheme.

When replication is configured, a replication agent is started for each database. In the case of multiple database on the same host, each database has a separate replication agent.

Each replication agent can send updates to one or more subscribers and to receive updates from one or more masters. Each of these connections is implemented as a separate thread of execution inside the replication agent process. Replication agents communicate through TCP/IP stream sockets.

For maximum performance, the replication agent detects updates to a database by monitoring the existing transaction log. It sends updates to the subscribers in batches, if possible. Only committed transactions are replicated.

How

It detects conflict

Time-based conflict detection and resolution are used to establish precedence in case the same data is updated in multiple locations at the same time.

Configuration

TimesTen recommends the active standby pair configuration for highest availability.

Active standby pair

Active standby pair is the only replication configuration that you can use for replicating IMDB Cache.

An active standby pair includes:

  • an active database,
  • a standby database,
  • optional read-only subscriber databases,
  • and the tables and cache groups that comprise the databases.

Documentation / Reference


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