'Should I create a read replica or scale the DB instance?

I'm using AWS's RDS PostgresQL DB

I recently traced an application error to the database connections being maxed out, I temporarily scaled the instance to support more connections since AWS's default behaviour is to use the instance's memory to calculate the maximum number of connections.

Most of the connections are due to clients reading data, so should I create a read replica instead of scaling the server? I'm thinking of this in terms of best practices, costs, and effort

postgresql


Solution 1:[1]

It depends how much the IOPS are, if your app is read intensive and there are connections limitation as well. Read IOPS are directly related to EBS storage, if you are using general storage.

Thus if you are using general storage. First look at your Read IOPS, if they are on average higher than STORAGE_IN_GB*3 then go for a read replica.

Otherwise just connection issue should be fixed by scaling the instance up vertically.

Sources

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Source: Stack Overflow

Solution Source
Solution 1 Faizan Shah

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