Re: Feature Proposal: Connection Pool Optimization - Change the Connection User

Hi Todd!

> I have just joined to start a community consultation process for a proposal. I just finished the proposal document, I spent time writing a Problem and Solution section, and I have done quite a bit of upfront exploration of the code.
>
> See:
>
> * Google Document with Commenting turned on https://docs.google.com/document/d/1u6mVKEHfKtR80UrMLNYrp5D6cCSW1_arcTaZ9HcAKlw/edit?usp=sharing. Feel free to request Edit access.
> * The current PDF version is attached too for archive purposes

I think you are right: the ability to reconnect to the same DB with another user would be beneficial for connection poolers.
Currently, PgBouncer\Odyssey maintains a lot of small pools - one for each user, while having a big one would be great.
From my experience, most of the cost of opening a new server connection comes from a fork() and subsequent CoW memory allocations.
And these expenses would be not necessary if we could just send a new Startup message after the Terminate ('X') message.
But this effectively would empty out out all backend caches.
Yet the feature seems useful from my PoV.

Best regards, Andrey Borodin.