1. Cache Guide
  2. Methods for Transmitting Changes Between TimesTen and Oracle Databases
  3. Automatically Refreshing a Cache Group
  4. AUTOREFRESH Cache Group Attribute Overview
  5. Autorefresh Interval and State Settings

Autorefresh Interval and State Settings

The autorefresh interval determines how often autorefresh operations occur in minutes, seconds or milliseconds.

Cache groups with the same autorefresh interval are refreshed within the same transaction. You can specify continuous autorefresh with an autorefresh interval of 0 milliseconds. With continuous autorefresh, the next autorefresh cycle is scheduled as soon as possible after the last autorefresh cycle has ended.

In TimesTen Classic, you can manually initiate an immediate autorefresh operation with the ttCacheAutorefresh built-in procedure. See ttCacheAutorefresh in Oracle TimesTen In-Memory Database Reference.

The autorefresh state can be set to ON, OFF, or PAUSED.

  • ON: Autorefresh operations are scheduled by TimesTen when the cache group's autorefresh state is ON.

  • OFF: When the cache group's autorefresh state is OFF, committed changes on the cached Oracle Database tables are not tracked. When you change the state from OFF to ON, a full autorefresh is performed.

  • PAUSED: When the cache group's autorefresh state is PAUSED, committed changes on the cached Oracle Database tables are tracked in the Oracle database, but are not automatically refreshed to the TimesTen cache tables until the state is changed to ON.

By default, a cache group is created with autorefresh state set to PAUSED. This provides you a choice of how and when the initial full load is performed.

  • If the data in the Oracle database is large, then an initial full load of the cache group can prove to be time consuming. The recommended option is to run a manual load with parallelism with the LOAD CACHE GROUP... PARALLEL statement. The autorefresh state automatically changes to ON after the initial load completes.

  • If the data on the Oracle database is small, change the state to ON with an ALTER CACHE GROUP. Changing the state to ON when an initial load has not yet been performed causes the initial load to be performed and autorefresh operations to start.

After the initial load is completed, you can change the state to PAUSED at any time. When you change the state to ON, then incremental autorefresh resumes for static cache groups that were created with incremental autorefresh.

If the data on the Oracle database is too large to perform an initial full load, you can disable all full load operations. See Disabling Full Autorefresh for Cache Groups.