1. Cache Guide
  2. Cache Performance
  3. Improving AWT Throughput
  4. Improving AWT Throughput with Parallel Propagation to the Oracle Database
  5. Configuring Batch Size for Parallel Propagation for AWT Cache Groups

Configuring Batch Size for Parallel Propagation for AWT Cache Groups

When using AWT cache groups, TimesTen batches together one or more transactions that are 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. Once the maximum number of rows is reached, TimesTen includes the rest of the rows in the transaction (TimesTen does not break up any transactions), but does not add any more transactions to the batch.

For example, a user sets the CacheParAwtBatchSize to 200. For the next AWT propagation, there are three transactions, each with 120 rows, that need to be propagated and applied to the Oracle database. TimesTen includes the first two transactions in the first batch for a total of 240 rows. The third transaction is included in a second batch.

The default value for the CacheParAwtBatchSize parameter is 125 rows. The minimum value is 1. See ttDBConfig in the Oracle TimesTen In-Memory Database Reference.

You can retrieve the current value of CacheParAwtBatchSize as follows: 

call ttDBConfig('CacheParAwtBatchSize');
< CACHEPARAWTBATCHSIZE, 125 >
1 row found.

You can set the CacheParAwtBatchSize parameter to 200 as follows: 

call ttDBConfig('CacheParAwtBatchSize','200');
< CACHEPARAWTBATCHSIZE, 200 >
1 row found

Set the CacheParAwtBatchSize parameter only when advised by Oracle Support, who analyzes the workload and any dependencies in the workload to determine if a different value for CacheParAwtBatchSize could improve performance. Dependencies exist when transactions concurrently change the same data. Oracle Support may advise you to reduce this value if there are too many dependencies in the workload.