What are the limitations and restrictions on the use of PostgreSQL?

PostgreSQL is a powerful relational database management system, but it has some limitations and usage features:

• Data type restrictions: For example, the maximum string size is limited to 1 GB, and the maximum table size is 32 TB (depending on the file system).
• Column count restrictions: Up to 1600 columns per table.
• Index restrictions: Up to 32 indexes per table.
• Transaction restrictions: PostgreSQL supports ACID, but very high concurrency can lead to locks and deadlocks.
• Parallelism restrictions: Parallel queries are supported, but not all operations can be parallelized.
• Extension restrictions: Not all third-party extensions are compatible with every version of PostgreSQL.

Additionally, it is important to consider configuration settings that affect performance and database behavior, such as the maximum number of connections, shared_buffers size, etc.