Re: Multiple startup messages over the same connection - Mailing list pgsql-hackers

From Vladimir Churyukin
Subject Re: Multiple startup messages over the same connection
Date
Msg-id CAFSGpE1Lnr-VJG-RER=otS+rMJzB2-GtuQSZNfGmUZ-k1nt-9g@mail.gmail.com
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In response to Re: Multiple startup messages over the same connection  (Heikki Linnakangas <hlinnaka@iki.fi>)
List pgsql-hackers
On Mon, Jan 22, 2024 at 11:43 PM Heikki Linnakangas <hlinnaka@iki.fi> wrote:
On 22/01/2024 21:58, Vladimir Churyukin wrote:
> A question about protocol design - would it be possible to extend the
> protocol, so it can handle multiple startup / authentication messages
> over a single connection? Are there any serious obstacles? (possible
> issues with re-initialization of backends, I guess?)
> If that is possible, it could improve one important edge case - where
> you have to talk to multiple databases on a single host currently, you
> need to open a separate connection to each of them. In some cases
> (multitenancy for example), you may have thousands of databases on a
> host, which leads to inefficient connection utilization on clients (on
> the db side too). A lot of other RDBMSes  don't have this limitation.

The protocol and the startup message are the least of your problems.
Yeah, it would be nice if you could switch between databases, but the
assumption that one backend operates on one database is pretty deeply
ingrained in the code.
  
Yes, I suspected that's the reason why it was not implemented so far,
but what's the main problem there?
Is the issue with the global data cleanup / re-initialization after the database is changed?
Is it in 3rd party extensions that assume the same and may break?
Anything else?

-Vladimir Churyukin

 
 

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