Re: Some questions about Postgres

> On Nov 3, 2022, at 10:38, Siddharth Jain <siddhsql(at)gmail(dot)com> wrote:
> I read an old article comparing MySQL to Postgres and wanted to get answers to following questions.

Given your questions, I suspect that you read the technical note from Uber about why they switched back to MySQL from PostgreSQL. There are quite a few responses out there to it, including:

https://thebuild.com/presentations/uber-perconalive-2017.pdf

To answer the specific questions:

1. Yes, all PostgreSQL indexes point directly to tuples on disk. They do not point to a primary key (which a table might not even have).

2. Yes, each backend connection to PostgreSQL is a separate process. The usual way of mitigating any performance issues this might introduce is to use a pooler such as pgbouncer.

3. This is equivalent to PostgreSQL's shared buffers.