Refactor the implementation of the tables in the information_schema.

[killme2008]

What type of enhancement is this?

Refactor

What does the enhancement do?

There is a lot of redundant code in these table implementations; we can find a way to reduce it.

For example:

• Many pieces of code access all the catalogs, schemas, and tables in a loop; we can refactor them with macros or helper functions to streamline the process.
• The query predicates do not cover all the necessary columns, which can lead to bad performance.
• Some requests could be processed in batches to improve performance and reduce memory consumption.

Implementation challenges

No response