Cache Group Types

There are several cache group types from which you can choose depending on the application needs.

The most commonly used types of cache groups are:

• Read-only cache group

  A read-only cache group enforces a caching behavior in which committed changes on cached tables in the Oracle database are automatically refreshed to the cache tables in the TimesTen database. Using a read-only cache group is suitable for reference data that is heavily accessed by applications.

  TimesTen Classic supports all types of read-only cache groups. TimesTen Scaleout only supports static read-only cache groups with incremental autorefresh.

  See Read-Only Cache Group in this book and Using Cache Groups in TimesTen Scaleout in the Oracle TimesTen In-Memory Database Scaleout User's Guide.

• Asynchronous WriteThrough (AWT) cache group

  An AWT cache group enforces a caching behavior in which committed changes on cache tables in the TimesTen database are automatically propagated to the cached tables in the Oracle database in asynchronous fashion. Using an AWT cache group is suitable for high speed data capture and online transaction processing.

  Only TimesTen Classic supports AWT cache groups.

  See Asynchronous WriteThrough (AWT) Cache Group.

Other types of cache groups include:

• Synchronous writethrough (SWT) cache group

  An SWT cache group enforces a caching behavior in which committed changes on cache tables in the TimesTen database are automatically propagated to the cached tables in the Oracle database in synchronous fashion.

  Only TimesTen Classic supports SWT cache groups.

  See Synchronous WriteThrough (SWT) Cache Group.

• User managed cache group

  A user managed cache group defines customized caching behavior.

  For example, you can define a cache group that does not use automatic refresh or automatic propagation where committed changes on the cache tables are manually propagated or flushed to the cached Oracle Database tables.

  You can also define a cache group that uses both automatic propagation in synchronous fashion on every table and automatic refresh.

  Only TimesTen Classic supports user managed cache groups.

  See User Managed Cache Group.

• Hybrid cache group

  All other cache groups require multiple table cache groups to have strict parent-child relationships for all tables on a TimesTen database as well as the Oracle database. With hybrid cache groups, the cache tables on a Oracle database must be related, but the root (parent) table must only exist on the TimesTen database. That is, you can dynamically load from cache tables that do not have a root table on the Oracle database. A hybrid cache group is a dynamic read-only cache group where the root table is created in the TimesTen database and does not exist in the Oracle database.

  See Hybrid Cache Group.