ClickHouse is a database optimized for maximum throughput in records/second in any query. ClickHouse.Client inherits that philosophy - default connection settings are tuned to maximize throughput over network in multiple threads, by using Compression=true by default (starting with version 2.0).

If query latency is more important than throughput (i.e. there are a lot of queries returning small results), it is recommended to turn compression off

Clickhouse.Client uses multiple threads to insert data when using BulkCopy functionality. With versions <2.0, it is strongly recommended to enable compression since uncompressed stream can easily saturate 1Gbit/s network. Starting with 2.0, compression is turned on by default in all connections.