Investigate performance issues

[spezifisch]

This is more of a "note to self":

Re: #77 (comment)

Why is it so laggy on my setup?

[rkowalsk]

Browsing the songs in the queue is very laggy for me, is it what you're talking about ?

[xxxserxxx]

@spezifisch is it only stmps, or do you notice lagging with other clients? Have you tried it with, e.g. Tempo on your phone, or with another client?

I did provide a caching PR that should address the aggravation caused by the addition of album art; did you notice whether it helped?

The recent synced lyrics PR won't help any -- the data's far smaller, but no attempt to fork it out into a future value was made in that patch, and it's still more API calls made.

GetPlaylists is always slow, which is why I implemented it the way I did, with plenty of decoupling.

Have you played with making API calls with bog standard curl? I do this a lot for debugging, and combined with a tool like hyperfine, you can learn a lot about isolating your server performance. For example:

Given a call you know works:

curl "http://me:[email protected]:4533/rest/search3?u=me&c=stmps&p=supersecret&f=json&v=1.8.0&query=Doja%20Cat" |\
     jq . | \
    less

you can turn it into a benchmark with:

hyperfine 'curl "http://me:[email protected]:4533/rest/search3?u=me&c=stmps&p=supersecret&f=json&v=1.8.0&query=Doja%20Cat"'

For example (and reference), my gonic server's DB statistics are:

• folders: 2705
• albums: 1830
• artists: 2479
• album artists: 1071
• tracks: 17207

Searching for "Doja Cat" (lexically near the beginning) vs "ZZ Top" (near the end) gives me the following results:

Benchmark 1: curl http://.../rest/search3\?...\&query\=Doja%20Cat
  Time (mean ± σ):      43.6 ms ±   2.7 ms    [User: 3.0 ms, System: 5.1 ms]
  Range (min … max):    37.8 ms …  49.8 ms    64 runs

Benchmark 1: curl http://.../rest/search3\?...\&query\=ZZ%20Top
  Time (mean ± σ):      43.0 ms ±   2.7 ms    [User: 2.4 ms, System: 3.9 ms]
  Range (min … max):    37.2 ms …  51.7 ms    73 runs

so about the same.