Hi @benjamin
I love listing to music and producing music. I love the experience that Roon brings to exploring and listening to music. This is why I spend once more time describing the symptoms of the issue and where I assume the cause of the issue.
Based on my experience as IT professional with a PhD in computer science I know that it is not advisable to exclude possible explanation for a problem to early. This is why I have duly followed all suggestions that I received so far, even though none of them sounded like a plausible explanation for the symptoms.
From the exchange to far I get the impression that you don´t consider, that the cause for the issue is coming from the Roon software in combination with the underlying database. This was my assumption from the beginning of this thread in December and with all the evidence that is now available and also shared from other users I am even more convinced that the problem is not originating in hardware or network issues. That’s why I am happy that you are now looking into the database.
I fully accept that you use a public forum as the only support channel, but I hope there is an internal escalation path for issues that can´t be resolved peer-to-peer. At a certain moment the software engineering team should be involved. Maybe this already happened behind the scenes but based on our communication I can only guess that this has not happened yet.
Let me summarize the consistent pattern of the issue that provides evidence to my assumption that the problem originates in the combination of the Roon application software and the underlying database.
The delay only occurs for me in one very specific circumstance. I have to manually start playback of a track by pressing either “Play Now” or the “Next” button AND the playback time of a track has to be long enough for Roon to consider it relevant for usage statistics. In the user interface this is represented by increasing the play counter.
When the playback time of a track was so short that the playback counter is not incremented, there is no delay between playing back tracks.
The precise time of the delay is represented in the logfile entry “Trace: [library] endmutation”. The time shown for endmutation is the sum of the preceding times for the “Computed stats” entries.
There is no delay after restarting the Roon Core. The delay time is increasing over time. In my case this takes 6-8 hours until the delay times goes beyond 3-4 seconds.
Please correct me if there is a better explanation. For me it looks as if Roon updates the database entries (Genres, Performer, Album) for the creating the information that is shown on the Roon home page under “What you´ve listening to” every time the playback counter is incremented. My assumption is that over time some “garbage” is piling up in the database or that some indexes are not created or updated or similar DB maintenance stuff. This “garbage” is cleaned with every restart and resolves the delay temporarily.
I experience the same amount of delay on every endpoint that I am using (MacMini, Windows PC, iPad, iPhone) and also when the audio files are stored on the same machine as Roon Core and the Roon client.
One theory as to why this problem only affects a few users: I started using Roon 2 months ago and migrated 60,000 audio files from iTunes. During the first month, I rediscovered a lot of music and did a lot of cleanups, mostly in the genres and ratings area. My usage patterns may therefore be unusual since I frequently skip tracks and also jump from album to album. I assume that most users listen to consecutive tracks in playlists or albums. Then the situation I described above does not occur.