pg_otel

A loadable module for PostgreSQL that exports server log messages to an OpenTelemetry collector.

Getting Started

Add pg_otel to your shared_preload_libraries and restart PostgreSQL. Its default settings do nothing, so this is safe to leave in all the time.

# postgresql.conf
shared_preload_libraries = pg_otel

OpenTelemetry recommends running its collector as an agent on the same machine as the application generating telemetry data. If that is how your system is arranged, this module's default settings are for you!

If your collector is somewhere else, you need put its URL in otel.otlp_endpoint.

ALTER SYSTEM SET otel.otlp_endpoint TO 'https://my-collector:4318';

With that in place, the otel.export setting starts or stops the flow of logs. These settings affect every connection to PostgreSQL, so the server needs to reload to finally apply them.

ALTER SYSTEM SET otel.export TO 'logs';
SELECT pg_reload_conf();

You should see logs in your collector and connected logging systems right away. Congratulations! 🎉

If you want to stop exporting logs, reset otel.export to its empty default.

ALTER SYSTEM RESET otel.export;
SELECT pg_reload_conf();

Configuration

There are number of other OpenTelemetry settings that can be adjusted for your environment. Their respective environment variables also work.

            name            |        default        | unit |                       description
----------------------------+-----------------------+------+-----------------------------------------------------------
 otel.export                |                       |      | Signals to export over OTLP
 otel.otlp_endpoint         | http://localhost:4318 |      | Target URL to which the exporter sends signals
 otel.otlp_timeout          | 10000                 | ms   | Maximum time the exporter will wait for each batch export
 otel.resource_attributes   |                       |      | Key-value pairs to be used as resource attributes
 otel.service_name          | postgresql            |      | Logical name of this service

The following settings cannot be changed at this time:

            name            |         value         | unit |                       description
----------------------------+-----------------------+------+-----------------------------------------------------------
 otel.attribute_count_limit | 128                   |      | Maximum attributes allowed on each signal
 otel.otlp_protocol         | http/protobuf         |      | The exporter transport protocol