Re:Our Journey to PostgreSQL 12
by philipwhiuk2 on Monday January 25, 2021 @08:26PM
(#25911290)
The fact that the answer isn't "move to RDS where Amazon solves the problem for us, which isn't our core business as a relationships app" seems to me to be a massive failing of the RDS offering and cloud services in general.
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RDS can be.. expensive? Like by a lot?
If you want to do upgrades like this on RDS with minimal downtime you will end up doing the same process: Set up new servers, do logical replication, switch over.
The RDS update process is a single button and you have no way of knowing how long it will take. There are some tricks like turning off Multi AZ and taking a snapshot manually before starting the process but still - for large instances you could be waiting anywhere from 30 minutes to 3 hours for RDS to finish. With large instance types I have seen RDS take a full hour just to provision an instance, in the meantime you'll sit there hitting F5 not knowing if it will ever finish.
Only if they evaluated RDS and found it wanting. They don't even mention testing it.
It's not in the post, but I answered this in a separate thread. RDS doesn't let us provision as many IOPS as we need.
Apparently Aurora behaves differently, but I wasn't aware of that when we specced out the project.
Aurora charges $0.20 per 1 million requests...your IO would have gotten expensive. It's also still stuck on PostgreSQL 11.9.
RDS can do up to 64K PIOPS these days. If you need more than that, I would definitely advocate for re-architecture to split things out and/or shard. We're up to 40k PIOPS in one of our larger databases and fast approaching the time to make that jump ourselves..