Execution Profiles

Execution profiles provide a mechanism to group together a set of configuration options and reuse them across different query executions. These options include:

• Load balancing policy
• Retry policy
• Consistency levels
• Per-host request timeout

Execution profiles API is being introduced to help deal with the exploding number of configuration options, especially as the database platform evolves into more complex workloads.

This document explains how Execution Profiles relate to existing settings, and shows how to use the new profiles for request execution.

Using Execution Profiles

Initializing cluster with profiles

Execution profiles should be created when creating the Client instance with a name that identifies it and the settings that apply to the profile.

const aggregationProfile = new ExecutionProfile('aggregation', {
  consistency: consistency.localQuorum,
  loadBalancing: new DCAwareRoundRobinPolicy('us-west'),
  retry: myRetryPolicy,
  readTimeout: 30000,
  serialConsistency: consistency.localSerial
});

const client = new Client({ 
  contactPoints: ['host1'],
  localDataCenter,
  profiles: [ aggregationProfile ]
});

Note that while the above options are all the supported settings on the execution profiles, you can specify only the ones that are required for the executions, using the 'default' profile to fill the rest of the options.

Default execution profile

You can define a default profile, using the name 'default':

const client = new Client({ 
  contactPoints: ['host1'],
  localDataCenter,
  profiles: [ 
    new ExecutionProfile('default', {
      consistency: consistency.one,
      readTimeout: 10000
    }),
    new ExecutionProfile('time-series', {
      consistency: consistency.localQuorum
    })
  ]
});

The default profile will be used to fill the unspecified options in the rest of the profiles. In the above example, the read timeout for the profile named 'time-series' will be the one defined in the default profile (10,000 ms).

For the settings that are not specified in the default profile, the driver will use the default Client options.

Using an execution profile by name

Use the name to specify which profile you want to use for the execution.

client.execute(query, params, { executionProfile: 'aggregation' });

Using an execution profile by instance

You can also use the ExecutionProfile instance.

client.execute(query, params, { executionProfile: aggregationProfile });

Using default execution profile

When the execution profile is not provided in the options, the default execution profile is used.

client.execute(query, params);