Subject: state management on connections

From: Stefan Eissing <[email-masked]>
Date: Wed, 23 Jan 2013 10:40:54 +0100

With regards to state management on http2 connections and the burden it
imposes on servers, my understanding is:

- both endpoints of the communication built up the same "state" during
  header compression
- connection lifetime is ideally as long as clients want
- servers may run into problems regarding memory needs per connection
- clients have no problem keeping state

What if the server could somehow get rid of the state when it wants to,
without closing the connection?

Possibilities:
a) Introduce a "header reset" control frame 
b) Allow the server to retrieve the "state" from the client

Approach a) has the disadvantage of requiring communication when the
server just wants to deallocate resources.

Approach b) has the drawback that servers need to pull the state 
from the client while working on incoming requests after state clearing.
Also, certain compression schemes do require "state" to remain in sync
with requests. So retrieving state n+1 while decoding a request based
on state n might not work.

Have people really knowledgable in the server side considered
anything along these lines?

Stefan

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