Service Concurrency

The consumer groups of the predefined service names provide different levels of performance and concurrency. The available service names are different depending on your workload: Data Warehouse, Transaction Processing, or JSON Database.

In this topic, the "number of OCPUs" is the OCPU count shown in the Oracle Cloud Infrastructure Console.

If your application requires customized concurrency, you can modify the concurrency limit for the MEDIUM service. See Change MEDIUM Service Concurrency Limit for more information.

Service Concurrency Limits for Data Warehouse Workloads

The tnsnames.ora file provided with the credentials zip file contains three database service names identifiable as high, medium and low for Autonomous Database with Data Warehouse workloads.

The following shows the details for the number of concurrent statements for each connection service for Data Warehouse workloads.

Database Service Name Concurrent Statements

high

3

medium

1.26 × number of OCPUs

low

300 × number of OCPUs

For example, for an Autonomous Database with 16 OCPUs, the HIGH consumer group will be able to run 3 concurrent SQL statements when the MEDIUM consumer group is not running any statements. The MEDIUM consumer group will be able to run 20 concurrent SQL statements when the HIGH consumer group is not running any statements. The LOW consumer group will be able to run 4800 concurrent SQL statements. The HIGH consumer group can run at least 1 SQL statement when the MEDIUM consumer group is also running statements. When these concurrency levels are reached for the MEDIUM and HIGH consumer groups, new SQL statements in that consumer group will be queued until one or more running statements finish. With the LOW consumer group, when the concurrency limit is reached you will not be able to connect new sessions.

The following table shows sample concurrent connections values for a database with 16 OCPUs.

Database Service Name Number of Concurrent Queries

high

3

medium

20

low

Up to 4800

Service Concurrency Limits for Transaction Processing and JSON Database Workloads

The tnsnames.ora file provided with the credentials zip file contains five database service names identifiable as tpurgent, tp, high, medium, and low for Autonomous Database with Transaction Processing or JSON Database workloads.

The following shows the details for the default number of concurrent statements for each connection service for Transaction Processing or JSON Database workloads.

Database Service Name Concurrent Statements

tpurgent

300 × number of OCPUs

tp

300 × number of OCPUs

high

3

medium

1.26 × number of OCPUs

low

300 × number of OCPUs