Yes. A full performance of the entire special service in the Russian Orthodox Church can indeed last pretty much all night, but be aware that the time is filled with much more than music–litanies (petitions and responses), Scripture readings, prayers, etc. A composer wouldn’t have to come up with hours and hours of music. Also, the service is often/usually cut, with the full version being performed very rarely.I ran across a fascinating article describing a 1911 performance that reproduced the long form. It lasted from 6:00 PM to 1:50 AM the following morning, so almost eight hours. If certain parts of the service had been performed in an even earlier form, it would have lasted three or four more hours. Here’s a little snippet from the article: