clickhouse-js-node-troubleshooting/upstream-original/reference/compression.md

Compression Not Working

Applies to: all versions. Response compression was enabled by default in < 1.0.0 and disabled by default since >= 1.0.0 — you must explicitly enable it. Request compression has always been opt-in.

Both request and response compression are supported. Only GZIP is supported (via zlib).

import { createClient } from "@clickhouse/client";
const client = createClient({
  compression: {
    response: true,
    request: true,
  },
});

Compression enabled but getting an error?

If you enable compression.response: true and get a ClickHouse settings error, you are likely connecting as a readonly=1 user. Response compression requires the enable_http_compression setting, which read-only users cannot change.

See reference/readonly-users.md for the fix.

Compression enabled but response doesn't seem compressed?

• Verify your version-specific defaults — response compression was enabled by default in < 1.0.0 and is disabled by default in >= 1.0.0, so on newer versions you must enable compression.response: true explicitly.
• Check that the ClickHouse server has HTTP compression enabled (enable_http_compression = 1 in server config). By default this is enabled on ClickHouse Cloud and most self-hosted setups.
• Request compression (compression.request: true) compresses the request body sent to ClickHouse. It has no effect on the response.