ClickHouse Exporter
Export OpenTelemetry to ClickHouse.
| Telemetry Type | Support |
|---|---|
| Traces | ✅ |
| Logs | ✅ |
| Metrics | ✅ |
The ClickHouse exporter can be selected by passing --exporter clickhouse. The ClickHouse exporter has full support
for traces, logs, and metrics.
| 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-request-timeout | 5s | |
| --clickhouse-exporter-enable-json | ||
| --clickhouse-exporter-json-underscore | ||
| --clickhouse-exporter-user | ||
| --clickhouse-exporter-password | ||
| --clickhouse-exporter-retry-initial-backoff | (uses global exporter default) | |
| --clickhouse-exporter-retry-max-backoff | (uses global exporter default) | |
| --clickhouse-exporter-retry-max-elapsed-time | (uses global exporter default) |
Table naming
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.
Async inserts
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.
DDL
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.
JSON
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.