How to stop Redis queue backing up and timing out

So I am getting this error in a production environment when my application tries to do a Get to Redis

> Timeout awaiting response
(outbound=0KiB, inbound=0KiB, 30469ms elapsed, timeout is 30000ms),

The timeout is 30 seconds.. so It's a long time for a Get call to wait!

The error message from the StackExchange.Redis library says:

> inst: 0, qu: 0, qs: 299, aw: False, bw: SpinningDown, rs: ReadAsync,
> ws: Idle, in: 46478, in-pipe: 0, out-pipe: 0, mc: 1/1/0, mgr: 10 of 10
> available, IOCP: (Busy=0,Free=1000,Min=2,Max=1000), WORKER:
> (Busy=153,Free=32614,Min=2,Max=32767), POOL:
> (Threads=153,QueuedItems=522,CompletedItems=3890)

So my Analysis of this is the following:

1. There are 299 calls awaiting a response in total
2. It doesn't look like any of the IOCP Pool is being utlised?
3. Worker pool seems to be operating correctly
4. "Pool" seems to have 522 queuedItems (I assume waiting execution)

I have used this page (Redis Timeout documentation) to try see whats going on

And I have ran the SlowLog command to analyse slow running queries, but they all seem to be executing in a timely manner

I am running a slightly older version of the library (1 year old) V2.5.61. But not sure that would make too much of a difference

Why has my pool got 522 pending items? and why is the IOCP not being utilised at all? Do I need to change something in my application or is this just bottlenecking because it doesnt have enough CPU to deal with the demand

I ended up setting the ThreadPool MinThreads to 100 which resolved the issue

ThreadPool.SetMinThreads(100, 100);

The number of minThreads depends on the system

Supporting information around setting min thread values

• https://stackexchange.github.io/StackExchange.Redis/Timeouts#are-you-seeing-a-high-number-of-busyio-or-busyworker-threads-in-the-timeout-exception
• https://stackoverflow.com/questions/57932586/stackexchange-redis-timeouts-and-how-to-set-my-minimum-thread-pool-number-in-ne/59261867#59261867