Re: Question: merit / feasibility of compressing frontend

Hi Tom,

Tom Lane wrote:
>
> Doug McNaught <doug(at)wireboard(dot)com> writes:
> > I think the big obstacle to putting compression into PG is needing to
> > extend the FE/BE protocol for negotiating compression, and the possible
> > client compatibility issues that raises. We already have SSL
> > negotiation working, though...
>
> Yup. Seems like a more useful exercise would be to lobby the SSL people
> to include compression as an option in SSL connections. That would
> solve the problem not only for PG, but every other application that uses
> SSL ...

We can all see the merits of having a compressed data stream, especially
in those situations where the byte count if more important than a CPU
cost.

However, I'd like to point out that SSL isn't feasible to use in all
situations, so having to enable SSL to gain compression would be a pain.

If someone's willing to put the time into this, then compression without
SSL feels like a good idea. Not everyone uses SSL. Bad network latency
has a very undesirable effect on the establishment of SSL connections,
and this is especially of interest in those cases where people need to
get short "bursty" amounts of SQL data across a connection as fast as
possible. Aka, client using a frontend app to remote databases over a
modem, and not using persistent connections.

Establishment of an individual SSL session using OpenSSL can take over a
second in this case. Not consistently-always, but I had to time it (on
fast hardware too) for a contract recently when deciding on network
layer transports.

Hope this gives some decent food for thought.

:-)

Regards and best wishes,

Justin Clift

> regards, tom lane
>
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