Replicating Cache Groups Within Active Standby Pairs
An active standby pair that replicates a read-only cache group or an asynchronous writethrough (AWT) cache group can change the role of the cache group automatically as part of failover and recovery. This helps ensure high availability of cache instances with minimal data loss.
See Replicating an AWT Cache Group and Replicating a Read-Only Cache Group to understand the benefits of using cache groups within an active standby pair.
Note:
TimesTen does not support replication of a user managed cache group or a synchronous writethrough (SWT) cache group in an active standby pair.
The following sections describe how to set up an active standby pair with cache groups:
You can also create a special disaster recovery read-only subscriber when you set up active standby replication of an AWT cache group. This special subscriber, located at a remote disaster recovery site, can propagate updates to a second Oracle database, also located at the disaster recovery site. See Using a Disaster Recovery Subscriber in an Active Standby Pair.
Setting Up an Active Standby Pair with an AWT Cache Group
With the active standby pair replication scheme, you must replicate all AWT cache groups. You can create the cache groups on the active master either before or after the active standby pair replication scheme is created.
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Before the creation of active standby pair: You can create cache groups on the active master before the active standby pair replication scheme is created. Then, create the active standby pair replication scheme and perform a distribution to include the cache groups. For detailed instructions on creating AWT cache group and then including it within a new active standby pair , see Replicating Cache Tables in TimesTen Classic in Oracle TimesTen In-Memory Database Cache Guide.
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After creation of active standby pair: You can create cache groups on the active master after the active standby pair replication scheme is created. Then, perform a distribution to include the cache groups. See Making Other Changes to an Active Standby Pair.
Either way, cache groups are added to the active standby pair replication scheme after you perform a distribution to include these cache groups.
Setting Up an Active Standby Pair with a Read-Only Cache Group
With the active standby pair replication scheme, you can choose to replicate any read-only cache groups. You can create the cache groups on the active master either before or after the active standby pair replication scheme is created.
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Before the creation of active standby pair: You can create cache groups on the active master before the active standby pair replication scheme is created. Then, create the active standby pair replication scheme and perform a distribution to include the cache groups. See Creating a Read-Only Cache Group to Include Within a New Active Standby Pair.
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After creation of active standby pair: You can create cache groups on the active master after the active standby pair replication scheme is created. See Making Other Changes to an Active Standby Pair.
Either way, cache groups are added to the active standby pair replication scheme after you perform a distribution to include these cache groups.
Creating a Read-Only Cache Group to Include Within a New Active Standby Pair
You can set up an active standby pair that replicates cache tables in a read-only cache group.
Before you create a database, see the information in these sections:
To set up an active standby pair that replicates a local read-only cache group, complete the following tasks: