Chat/discussion feature is broken

[bklang]

The loading icon (see attached) appears forever. We should either fix or hide this feature.

[bklang]

The PR addressed code issues (likely introduced by our recent upgrade work), but the chat feature still does not work in staging. The reason is that the tier of MongoDB to which we subscribe does not allow the mapReduce feature. You can see this in the API response: [8000:AtlasError]: CMD_NOT_ALLOWED: mapReduce (on 2flaredown-staging-lind-shard-00-02.ql1v6.mongodb.net:27017). The restriction is mentioned in the MongoDB service documentation

I can think of two options at the moment:

• Upgrade to at least an M10 instance with MongoDB, which would cost somewhere around $60/mo
• Refactor the queries to avoid mapReduce. This happens in two places right now.

[benlangfeld]

The PR addressed code issues (likely introduced by our recent upgrade work), but the chat feature still does not work in staging. The reason is that the tier of MongoDB to which we subscribe does not allow the mapReduce feature. You can see this in the API response: [8000:AtlasError]: CMD_NOT_ALLOWED: mapReduce (on 2flaredown-staging-lind-shard-00-02.ql1v6.mongodb.net:27017). The restriction is mentioned in the MongoDB service documentation

I can think of two options at the moment:

• Upgrade to at least an M10 instance with MongoDB, which would cost somewhere around $60/mo
• Refactor the queries to avoid mapReduce. This happens in two places right now.

You know, I'd love to know why we're using Mongo for this rather than Postgres. I havn't looked into it, so from the code it might be obvious, but it should probably be mentioned at a high level in the readme. There's a chance that what feels like it should be relational data could be much more performantly handled in a relational database.

We should at least be careful not to pull huge computations into the Rails process and blow out memory consumption there.