Predefined Database Service Names for Autonomous Transaction Processing

Autonomous Transaction Processing provides five pairs of database services to use when connecting to your dedicated database. In each pair, one of the pair provides a secure TCP (TCPS) connection using the TLS protocol, and the other provides a TCP connection. In all other respects, the two members of a pair are the same.

These five pairs of connection services are designed to support different kinds of database operations:

  • tpurgent_tls and tpurgent: For high priority, time critical transaction processing operations.
  • tp_tls and tp: For typical transaction processing operations.
  • high_tls and high: For high priority reporting and batch operations.
  • medium_tls and medium: For typical reporting and batch operations.
  • low_tls and low: For low priority reporting and batch operations.

Note:

Oracle strongly recommends that you use the secure TCP (TCPS) databases services. The TCP database services are provided for backward compatibility with applications that cannot use TLS-encrypted TCPS connections.

The following table compares these characteristics of these five pairs of database services:

  • Degree of Parallelism: Parallel execution is a feature of Oracle Autonomous Database that creates and uses multiple processes to execute a single SQL statement. The degree of parallelism specifies the number of processes that can be used. Due to the performance cost of creating additional processes, parallel execution is generally worthwhile when:

    • The query references a large data set.
    • There is low concurrency.
    • Elapsed time is important.
  • Resource Shares: Oracle Autonomous Database uses Oracle Database Resource Manager consumer groups to provide different resource allocations to each pair of database services. Resources shares define the guaranteed fraction of resources a consumer group will be granted. For example, tpurgent_tls and tpurgent, with a resource share of 12, are guaranteed 12/27 (27=12+8+4+2+1) of resources. However, any consumer group can use more than the guaranteed amount of a resource when no resource contention exists.

  • Concurrent Statements: The maximum number SQL statements that the database can be processing for a consumer group before statements are queued.

  • FAN Enabled: Whether Fast Application Notification is enabled by default.

  • TAC Enabled: Whether Transparent Application Continuity is enabled by default.

Service Names Degree of Parallelism Resource Shares Concurrent Statements FAN Enabled TAC Enabled
tpurgent_tls and tpurgent Set manually 12 CPU_COUNT × 100 Yes Yes
tp_tls and tp 1 8 CPU_COUNT × 100 Yes Yes
high_tls and high CPU_COUNT 4 3 Yes No
medium_tls and medium 4 2 CPU_COUNT × 1.25 Yes No
low_tls and low 1 1 CPU_COUNT × 100 Yes No

In this table, CPU_COUNT is the value of the CPU_COUNT initialization parameter for your dedicated database, which is equal to the CPU Core Count shown in the Oracle Cloud console.

Note:

After connecting to the database using one service, do not attempt to manually switch that connection to a different service by simply changing the consumer group of the connection. When you connect using a service, Autonomous Transaction Processing performs more actions to configure the connection than just setting its consumer group.