[64459]: [1-1] user=[unknown],db=[unknown],host= WARNING: pg_getnameinfo_all() failed: Temporary failure in name resolution...
First thing I'd check is that DNS is functioning correctly (including local resolution settings or caching name resolvers).
In addition to what Steve mentioned, I've a vague recollection from running into this several years ago that this is triggered by having "log_hostname" enabled in your postgresql.conf.