We recently had to bring our Discourse forum on prem, and overall had a pretty painless experience. We have noticed, though, a pretty massive (10-15x) increase in time spent in Redis per transaction. This is the last three days: [image] and the same time period, the week before our migration: […

One other change to throw into the mix: Before we migrated, a user had to explicitly create an account in Discourse, and had to ‘log in’ to Discourse, even if already logged into their service account. Our auth changes integrate into Discourse’s SSO and when a user visits the forum, an account is a…

Is this redis inside the default Discourse docker container, self hosted Redis elsewhere, or Elasticache Redis? If using Elasticache Redis can you share the instance type? Discourse Prometheus can give you redis time per page type, like on the topic page and on the category page. Your graph can…

@Falco It is hosted outside of the container, not in Elasticache, but it’s closer to a m3.large- 2 cpu cores, 8gb RAM. Yeah, we can compare by transaction, the majority of time is spent in: MessageBus: [image] TopicsController#show: [image]

[image] mmayo: Yeah, we can compare by transaction, the majority of time is spent in: MessageBus: [image] mmayo: This, translates, though, into some real slowdowns on the front end, with our page load time increasing over a second on average. :thinking: a slightly slower message bus s…

I agree, I am not casting a ton of suspicion on the message bus, but since a lot of time is spent there is demonstrative of the change. This is from the week before we migrated: [image]

Hmmm, not to brag about it but our bare metal redis perf is a bit crazy with 2ms median / 8ms p99. Hard to get similar numbers in the cloud (right now 15ms median / 22ms p99 for Meta in AWS).

[image] Falco: Hmmm, not to brag about it but our bare metal redis perf is a bit crazy with 2ms median / 8ms p99. Fair. So to clarify, since most of this increase in redis time is in the message-bus, and with similar results to meta in TopicsController#show, maybe the increase in redis isn’t …

Yes. Are you using our mini-profiler? It’s great to track down some slow queries while browsing the site normally.

Huge increase in Redis use after changing hosts

Product Support Self-hosting

Falco (Falco) August 9, 2018, 7:05pm 5

a slightly slower message bus should not result in slower page load time. It’s for background tasks.

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Huge increase in Redis use after changing hosts

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