This feature compress WAL of streaming replication by zlib library. This reduce the load on the network. so it prevents the occurrence of streaming replication delay due to network bottlenecks. This is especially effective in environments where the network transfer speed is slow, such as when transferring data to a disaster prevention environment.

The compression/decompression process works by enabling the feature. so the throughput may decrease when the network is fast and the load is low. Therefore, it is necessary to judge the effectiveness in advance.