Magnus Hagander wrote:

> > I don't understand why you want to change the default.  Is it for
> > performance?  Has it been measured?
> >
> >
> Yes. I've run into it multiple times, but I haven't specifically measured
> it. But I've had more than one situation where turning it off has
> completely removed a performance problem.

Here's a test case retrieving 133000 rows representing
100Mbytes of text, that shows a 4x slowdown with ssl.
ssl_renegotiation_limit is set to 0 and the cache is warmed up
by repeated executions.

Without SSL:

$ time psql -At "postgresql://localhost/mlists?sslmode=disable"\
  -c "select subject from mail" -o /dev/null
real    0m1.359s
user    0m0.544s
sys     0m0.084s

With SSL:
$ time psql -At "postgresql://localhost/mlists?sslmode=require"\ 
  -c "select subject from mail" -o /dev/null
real    0m5.395s
user    0m1.080s
sys     0m0.116s

The CPU is Intel(R) Xeon(R) CPU E31230 @ 3.20GHz, OS is Debian7
with kernel 3.2.0-4.

Personally I think that TLS for local networking is wrong as a default, and
it's unfortunate that distros like Debian/Ubuntu end up using that.

Best regards,
Daniel Vérité
PostgreSQL-powered mailer:
Twitter: @DanielVerite

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