Redis issues

[Linda A]

I've posted previously about major problems with my forum, namely that the ibf_data_store table (it's InnoDB, as are all the rest) would randomly start filling the processlist with updates, presumably after a flush of the table. Invision's support just says it's a server issue. After much searching around, I found one user who had said his forum started performing much better when he turned off the use of caches such as Redis/memcached (i.e. selecting the 'No Cache' setting). That seemed counter-intuitive, but I gave it a try...

... and now things work very well. That said, I really dislike the fact that I can't use Redis, since I can see MySQL is working extra hard and load is a little higher than I want with ~1500 concurrent users, and as it happens we tend to get spikes of much more each weekend so that seems worrisome.

So, Redis is the problem, somehow... or maybe IPS's implementation of how the forum software and Redis interact.

 

So, questions:

 

1) Has anyone else seen similar issues, and found a solution?

2) We're on Redis 3.2.3 -- should we try Redis 4 to see if that fixes the situation? What version of Redis are people using?

3) Is Memcached a better option than Redis? I see most people here seem to stick with it.