|Oracle® TimesTen Application-Tier Database Cache User's Guide
11g Release 2 (11.2.2)
This section summarizes the new features of TimesTen Application-Tier Database Cache release 11.2.2 that are documented in this guide and provides links to more information.
The Oracle In-Memory Database Cache is now named the Oracle TimesTen Application-Tier Database Cache. Previous references to "IMDB Cache" are now referenced as "TimesTen Cache."
You can manage the size of the reclaim buffer for the cache agent used to process autorefresh. You can also manage the size of the reclaim buffer for the replication agent when using an active standby pair replication scheme that includes autorefresh cache groups. See "Improving performance when reclaiming memory during autorefresh operations."
UNLOAD CACHE GROUP now supports the
ROWS clause to specify a commit frequency. See "Unloading a cache group". However, if you use this clause, the unload operation does not execute across grid members. For details, see "Unloading a cache group across all grid members".
If you are using parallel propagation for AWT cache groups, any missing unique index, unique constraint, or foreign key constraint on the columns of the cached Oracle Database tables cause the propagation of transactions to be serialized to the Oracle database. See "Table constraint restrictions when using parallel propagation for AWT cache groups".
Prolonged use or a heavy workload of the change log tables can result in fragmentation of the tablespace. In order to prevent degradation of the tablespace from fragmentation of the change log tables, TimesTen calculates the fragmentation for the tablespace and provides a way to defragment the tablespace and reclaim the space. For more details, see "Defragmenting change log tables in the tablespace".
Oracle Database permanent errors logged to the
awterrs text file can now also be written in XML format. For more details, see "Reporting Oracle Database permanent errors for AWT cache groups".
At certain times, you may execute large transactions, such as for the end of the month, the end of a quarter, or the end of the year transactions. You may also have situations where you modify or add a large amount of data in the Oracle database over a short period of time. For read-only, autorefresh cache groups, TimesTen could potentially run out of permanent space when an autorefresh operation applies either one of these cases. Therefore, for these situations, you can configure an autorefresh transaction limit, where the large amount of data is broken up, applied, and committed over several smaller transactions. For details, see "Improving execution of large transactions when using incremental autorefresh for read-only cache groups".
You can now set the value for the
CacheAWTMethod first connection attribute with the
ttDBConfig built-in procedure. See "Improving AWT throughput".
When using AWT cache groups, you can use parallel propagation for AWT cache groups that batches together one or more transactions to be applied in parallel to the back-end Oracle database. The
CacheParAwtBatchSize parameter configures a threshold value for the number of rows included in a single batch. See "Configuring batch size for parallel propagation for AWT cache groups".
There are now a set of recommended steps when scheduling a shutdown of an active standby replication pair with AWT cache groups. For more information, see "Recommended method for a scheduled shutdown of an active standby pair with AWT cache groups".
You can perform a dynamic load for queries with equality conditions on all columns in primary keys, with equality conditions on all columns in unique indexes, or with a mixture of equality or
IS NULL conditions on all columns in unique indexes (provided that at least one equality condition is used). For more details, see "Dynamically loading a cache instance".
You can manually initiate a check for missing constraints for AWT cache groups with the
ttCacheCheck built-in procedure. After any schema change on the Oracle database, you should perform an manual check for missing constraints by executing
ttCacheCheck on the TimesTen database. See "Manually initiate check for missing constraints".
New instructions have been added on how to backup and restore a TimesTen database that contains one or more cache groups. For more details, see "Backing up and restoring a database with cache groups".
A new tool, the TimesTen Cache Advisor, enables Oracle Database customers to determine whether the performance of an existing Oracle Database application can be improved if the application is used with TimesTen Cache. Cache Advisor generates recommendations of TimesTen cache group definitions based on the SQL usage in the Oracle Database application. For more information, see Chapter 10, "Using the Cache Advisor".
You can configure parallel propagation of changes in AWT cache tables to the corresponding Oracle Database tables using either the
CacheAWTParallelism data store attributes. See "Configuring parallel propagation to Oracle Database tables".
If you are using parallel propagation, any unique index, unique constraint, or foreign key constraint on the columns of the cached tables in the Oracle Database must also be created on the cached tables in the AWT cache group. See "Configuring parallel propagation to Oracle Database tables".
You can configure parallel propagation of changes in AWT cache tables to the corresponding Oracle Database tables. See "Configuring parallel propagation to Oracle Database tables".
The default value for the
CacheAWTMethod first connection attribute has changed. See "Improving AWT throughput".
You can obtain information about the grid node where a global query is being executed. See "Obtaining information about the location of data in the cache grid".
You can perform a local join when executing a global query. See "Performing global queries with local joins".