Support Specifying Table Schema for PostgreSQL Dictionary Source

Why it matters

This feature allows users to explicitly define the schema of a PostgreSQL source table used for dictionaries in ClickHouse. It resolves issues related to schema ambiguity or changes in the source table, improving reliability and flexibility when integrating PostgreSQL dictionaries.

How to use it

When configuring a postgresql dictionary source, users can specify the table schema to ensure correct dictionary loading and updates. This typically involves adding the schema name in the dictionary source configuration under the relevant parameters.