Clickhouse Exporter
Export OpenTelemetry metrics, logs and traces to Clickhouse.
| Telemetry Type | Support |
|---|---|
| Traces | Alpha |
| Logs | Alpha |
The Clickhouse exporter can be selected by passing --exporter clickhouse. The Clickhouse exporter only supports logs
and traces at the moment.
| Option | Default | Options |
|---|---|---|
| --clickhouse-exporter-endpoint | ||
| --clickhouse-exporter-database | otel | |
| --clickhouse-exporter-table-prefix | otel | |
| --clickhouse-exporter-compression | lz4 | none, lz4 |
| --clickhouse-exporter-async-insert | true | true, false |
| --clickhouse-exporter-enable-json | ||
| --clickhouse-exporter-json-underscore | ||
| --clickhouse-exporter-user | ||
| --clickhouse-exporter-password |
The Clickhouse endpoint must be specified while all other options can be left as defaults. The table prefix is prefixed
onto the specific telemetry table name with underscore, so a table prefix of otel will be combined with _traces to
generate the full table name of otel_traces.
The Clickhouse exporter will enable async inserts by
default,
although it can be disabled server-side. Async inserts are
recommended for most workloads to avoid overloading Clickhouse with many small inserts. Async inserts can be disabled by
specifying:
--clickhouse-exporter-async-insert false.
The exporter will not generate the table schema if it does not exist. Use the clickhouse-ddl command for generating the necessary table DDL for Clickhouse. The DDL matches the schema used in the OpenTelemetry Clickhouse exporter.
Enabling JSON via the --clickhouse-exporter-enable-json will use the new
JSON data type in Clickhouse. This data
type is only available on the most recent versions of Clickhouse. Make sure that you enable JSON with --enable-json
when creating tables with clickhouse-ddl. By default, any JSON key inserted with a period in it will create
a nested JSON object. You can replace periods in JSON keys with underscores by passing the option
--clickhouse-exporter-json-underscore which will keep the JSON keys flat. For example, the resource attribute
service.name will be inserted as service_name.
The Clickhouse exporter is built using code from the official Rust clickhouse-rs crate.