Re: holding connections open: a modest proposal

Marc VanHeyningen (
Tue, 13 Sep 1994 00:20:58 +0200

Dave Kristol said:
>There has been some discussion here about keeping connections open
>between client and server after a transaction is complete. I don't
>recall seeing a resolution, however, so I want to put forth what I
>think is a simple solution, and I don't recall seeing anything
>comparable proposed.

Re the original proposal, the main thing missing is specification of
headers; the "Content-Length" header becomes mandatory whenever it is
nonzero if multiple transactions are happening.

For that matter, the general semantics of headers becomes a bit less
clear. Should request headers be re-transmitted by the client with
each request or be assumed by the server to remain the same from
request to request, for instance? Which ones?

John Franks said:
>While I know of no careful study I think there is considerable
>anecdotal evidence (well at least folklore) that holding the
>connection open is a bad idea. It may reduce network traffic but
>increases the load on the server.

Actually, I thought the idea was more to improve performance than to
reduce network traffic. But, in any case, it would be nice to know in
some empirical fashion that this change actually will produce
significant performance gains and will not increase server load.

It also provides extensions that are rather stream-centric. Up to
this point HTTP generally has not been like that. Should it be?

> Another proposal which has been discussed is to use MIME multi-part
> document format to make an HTML document with 20 images into a
> single document. The problem with this is that it represents
> substantial effort on the part of browser and server writers and
> is, for that reason, not likely to get implemented.

Indeed; it also produces some flexibility problems, since the
server has no way of knowing whether the client already has some of
the images cached, or even whether the client can or wishes to
retrieve and display the images at all.

Marc VanHeyningen  <>