Handling many relations

If your Postgres database has a large number of relations (in the thousands), Datadog recommends adding collect_database_size_metrics: false to your instance configuration for that database. When this setting is disabled, the Agent will not run the function pg_database_size() to collect database size statistics, which has worse performance on instances with a large number of tables.

instances:
  - dbm: true
    ...
    collect_database_size_metrics: false

Additionally, if you partition your data across tables, such that table definitions are identical except for the name, this can result in a large number or normalized queries:

SELECT * FROM daily_aggregates_001
SELECT * FROM daily_aggregates_002
SELECT * FROM daily_aggregates_003

In these cases, track these queries as a single normalized query using the replace_digits option, so all metrics for those queries are rolled up into a single query:

SELECT * FROM daily_aggregates_?

Add the replace_digits option to your database instance configuration in the Datadog Agent:

instances:
  - dbm: true
    ...
    obfuscator_options:
      replace_digits: true

Raising the sampling rate

If you have queries that are relatively infrequent or execute quickly, raise the sampling rate by lowering the collection_interval value to collect samples more frequently.

Set the collection_interval in your database instance configuration of the Datadog Agent. The default value is 1 second and can be seen in the postgres/conf.yaml.example.

Lower the value to a smaller interval:

instances:
  - dbm: true
    ...
    query_samples:
        collection_interval: 0.1