Predefined Database Service Names for Autonomous Databases

Autonomous Database provides multiple sets of database services to use when connecting to your dedicated database. In each set, one service provides a secure TCP (TCPS) connection using the TLS protocol, and another provides a TCP connection. The databases configured to use Autonomous Data Guard have two additional services with the same connection types (TCPS and TCP) to the standby database for read-only access.

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

• tpurgent_tls, tpurgent, tpurgent_ro_tls, and tpurgent_ro: For high priority, time critical transaction processing operations.
• tp_tls, tp, tp_ro_tls, and tp_ro: For typical transaction processing operations.
• high_tls, high, high_ro_tls, high_ro: For high priority reporting and batch operations.
• medium_tls, medium, medium_ro_tls, medium_ro: For typical reporting and batch operations.
• low_tls, low, low_ro_tls, low_ro: For low priority reporting and batch operations.

Key Characteristics of the Predefined Database Services

• Concurrent Statements: The maximum number of SQL statements that an Autonomous Database can be processing for a consumer group before queuing the statements.
• Degree of Parallelism: Parallel execution is one of the Oracle Autonomous Database's features 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.
  • The elapsed time is critical.
• Resource Shares: Oracle Autonomous Database uses Oracle Database Resource Manager consumer groups to provide different resource allocations to each database service pair. Resource Shares define the fraction of resources guaranteed to a consumer group. However, any consumer group can use more than its Resource Shares when no resource contention exists.
• FAN Enabled: Indicates if Fast Application Notification is enabled by default.
• TAC Enabled: Indicates if Transparent Application Continuity is enabled by default.

The following table compares the different sets of database services based on the characteristics discussed above.

Service Names	Degree of Parallelism	Resource Shares	Concurrent Statements	FAN Enabled	TAC Enabled
tpurgent_tls, tpurgent, tpurgent_ro_tls, and tpurgent_ro	Set manually	12	300 x OCPUs	Yes	Yes
tp_tls, tp, tp_ro_tls, and tp_ro	1	8	300 x OCPUs	Yes	Yes
high_tls, high, high_ro_tls, and high_ro	OCPUs	4	3	Yes	No
medium_tls, medium, medium_ro_tls, and medium_ro	4	2	1.25 × OCPUs	Yes	No
low_tls, low, low_ro_tls, and low_ro	1	1	300 x OCPUs	Yes	No

Where the number of OCPUs is the CPU Core Count shown in the Oracle Cloud console.

Note:

After connecting to your dedicated database using a service, do not attempt to switch that connection to a different service by changing the consumer group of the connection manually. Please note that the Autonomous Database performs more actions to configure the connection than just setting its consumer group while connecting to your dedicated database using a service.