Re: [HACKERS] Adding connection id in the startup message - Mailing list pgsql-hackers

From David G. Johnston
Subject Re: [HACKERS] Adding connection id in the startup message
Date
Msg-id CAKFQuwa0Ao=vikg5n0GgD6ecVA+rM+5JwPg1PmhPeYhgiv+_LA@mail.gmail.com
Whole thread Raw
In response to Re: [HACKERS] Adding connection id in the startup message  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
On Wed, Jun 21, 2017 at 12:15 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> I think the problem is real,
> but I'm not sure that this is the best solution.  On the other hand,
> I'm also not entirely sure I understand the proposal yet.

Given the problems with changing the protocol it does seem like
generalizing away from "connection id" to "arbitrary payload" would be
useful.

Like, add a new "attachment map" area where any application-aware node
that encounters the message can attach data.  If some node further
downstream sends a response message the contents of the attachment map
would be sent back as-is.

The advantage of "connection id" is that the messages are still of
fixed size whereas the more flexible arrangement would necessitate
that message sizes vary.  In return middleware gets a place to store
session information that can be used more broadly than a simple
externally generated connection id.

David J.



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