Re: TCP network cost

> python w/ psycopg (or psycopg2), which wraps libpq. Same results w/
> either version.

    I've seen psycopg2 saturate a 100 Mbps ethernet connection (direct
connection with crossover cable) between postgres server and client during
a benchmark... I had to change the benchmark to not retrieve a large TEXT
column to remove this bottleneck... this was last year so versions are
probably different, but I don't think this matters a lot...

> Note the 'bare' transfer times added above. Nothing to write home about
> (~3Mb/sec) but another order of magnitude faster than the postgresql
> transfer.

    You should test with sending a large (>100 MB) amount of data through
Netcat. This should give you your maximum wire speed. Use /dev/null as the
test file, and use "pv" (pipe viewer) to measure throughput :

box 1 : pv < /dev/zero | nc -lp 12345
box 2 : nc (ip) 12345 >/dev/null

    On gigabit lan you should get 100 MB/s, on 100BaseT about 10 MB/s. If you
dont get that, there is a problem somewhere (bad cable, bad NIC, slow
switch/router, etc). Monitor CPU during this test (vmstat). Usage should
be low.