CacheAWTMethod

Determines whether asynchronous writethrough propagation uses the PL/SQL execution method or SQL array execution method to apply changes to the Oracle database server.

By default, asynchronous writethrough (AWT) uses PL/SQL execution method, CacheAWTMethod=1. AWT bundles all pending operations into a single PL/SQL collection that is sent to the Oracle database server to be executed. This method can improve AWT throughput when there are mixed transactions and network latency between TimesTen and the Oracle database server.

The SQL array execution to apply changes within TimesTen to the Oracle database works well when the same type of operation is repeated. For example, array execution is very efficient when a user does an update that affects several rows of the table. Updates are grouped together and sent to the Oracle database server in one batch.

PL/SQL execution method transparently falls back to array execution mode temporarily when it encounters one of the following:

• A statement that is over 32761 bytes in length.

• A statement that references a column of type BINARY FLOAT, BINARY DOUBLE and VARCHAR of length greater than 4000 bytes.

Specify the SQL execution method, CacheAWTMethod=0, if any AWT cache group contains a VARBINARY column.

The SYSTEMSTATS table contains information about the number of times the execution method temporarily falls back to SQL array execution.

Note:

• This attribute can also be set through the ttDBConfig built-in procedure, which overrides the connection attribute setting. See ttDBConfig.

• Use the same AWT execution method on all TimesTen nodes in any active standby pair replication scheme.

Required Privilege

Only the instance administrator can change the value of this attribute.

Usage in TimesTen Scaleout and TimesTen Classic

This attribute is supported in TimesTen Classic but not supported in TimesTen Scaleout.

Setting

Set CacheAWTMethod as follows:

Where to set the attribute	How the attribute is represented	Setting
C or Java programs or UNIX and Linux systems odbc.ini file in TimesTen Classic	CacheAWTMethod	0 - Use SQL array execution method. 1 (default) - Use PL/SQL collections and anonymous blocks (PL/SQL execution method).
Windows ODBC Data Source Administrator	Not applicable