BUG - `pg_catalog` and `information_schema` excluded even if included in config

[emouawad]

By default db2rest excludes pg_catalog and information_schema even if they are added to the INCLUDED_SCHEMAS env variable and profile yaml schemas

pg_catalog is still a schema that contains tables that are useful to be queried.

I consider this a bug because even if included as a schema they are not loaded - please allow loading those schemas if enabled via config.

db2rest/db2rest-core/rdbms-support/src/main/java/com/homihq/db2rest/jdbc/sql/PostgreSQLDataExclusion.java

Line 20 in d8b3e64

List<String> excludedSchemas = Arrays.asList("pg_catalog", "information_schema");

[kdhrubo]

@emouawad - db2rest philosophy has been high performance and high security from outset. We did not want to allow access to these system schemas and tables. Also if my memory goes well - these schemas seem to have many tables and DB2Rest relies on underlying JDBC driver meta data extraction. These let to long startup time as the schema cache is created at startup. This was observed for Oracle, PG14 etc. Hence the early adapters and team excluded these tables.

Having said that - an exception can be done, the user of the platform can decide to lower the security with possibility of high startup time. It will be very easy to add an ENVIRONMENT VARIABLE - INCLUDE_SYSTEM_SCHEMA = true | false - then the system schemas can be easily included. Let us know how this sounds.

[emouawad]

Thanks for the explanation: that sounds fair enough.
INCLUDE_SYSTEM_SCHEMA should do for now if that's easier, but setting it per database in the yaml file would be even better.
thanks!

[kdhrubo]

INCLUDE_SYSTEM_SCHEMA will be per databases, but you want to include some schema from the system schemas not all hence you prefer to set it in INCLUDED_SCHEMAS - is this correct understanding?

[emouawad]

Ultimately yes controlling which schemas are to be included is better per database - but for now not excluding them by default for all should do.