I decided to do a little more research on the performance of server-side backup compression, which will be a new feature in PostgreSQL 15 unless, for some reason, the changes need to be reverted prior to release time. The network link I used for my previous testing was, as I mentioned, rather slow, and handicapped by both a VPN link and an SSH tunnel. Furthermore, I was testing using pgbench data, which is extremely compressible. In addition, at the time I did those tests, we had added support for LZ4 compression, but we had not yet added support for Zstandard compression. Now, however, we not only have Zstandard as an option, but it is possible to use the library's multi-threading capabilities. So, I wanted to find out how things would work out on a faster network link, with a better test data set, and with all the compression algorithms that we now have available.
