Amazon RDS for PostgreSQL: Configuration differences with PostgreSQL on EC2

Question

A customer has decided to start using RDS for the new versions of their offering. They are interested in knowing what are the main differences they should take into account when moving from PostgreSQL on EC2 to RDS. I have already found the list of supported features but I wonder if we have any further information regarding:

Parameters whose default value in RDS is different from the one in self-managed PostgreSQL.
Parameters that are not available or can't be modified for RDS
Any functionality that being available for both of them have different behaviors.

Thanks in advanced.

- Parameters whose default value in RDS is different from the one in self-managed PostgreSQL.
- Parameters that are not available or can't be modified for RDS
- Any functionality that being available for both of them have different behaviors.

Thanks in advanced.

AWS-User-8035775 · Accepted Answer

I am not aware of any document showing the parameters comparison. The easy option is to compare the output of [pg_settings][1] table on RDS and self-managed PostgreSQL.

You also need to spend some time on the the following:

- Extensions / Extension versions - Is the correct version of the extension available?
- Fdw/dblinks - On PostgreSQL to PostgreSQL FDW/Dblink is supported so check what is being used by customer.
- Special features like email or OS files access - no OS access is available so any functionality required OS access will not work.
- Pl/ Perl java python etc - Only the secure versions are supported. 
- Scheduled cron jobs - They need to be run from Lambda, Step Functions or an EC2 instance.

[1]: https://www.postgresql.org/docs/10/view-pg-settings.html

Amazon RDS for PostgreSQL: Configuration differences with PostgreSQL on EC2

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