Re: pg_connect takes 3.0 seconds

Oops, I meant to mention this too .... virtually all GigE and/or server
class NICs do TCP checksum offload.

Dimitri - it's unlikely that you have a hardware issue on the NIC, it's more
likely to be a cable problem or network congestion. What you want to look
for in the tcpdump capture is things like SYN retries.

A good way to test for cable issues is to use a ping flood with a large
packet size.

Cheers
Dave

Hang on a sec. You need to ignore bad checksums on *outbound* packets,
> because many (most?) Ethernet drivers implement some level of TCP
> offloading, and this will result in packet sniffers seeing invalid checksums
> for transmitted packets - the checksums haven't been generated by the NIC
> yet.
>
> Unless you know for sure that your NIC doesn't do TSO, ignore bad checksums
> on outbound packets from the local interface.
>
> --
> Craig Ringer
>
>
> --
> Sent via pgsql-performance mailing list (pgsql-performance(at)postgresql(dot)org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-performance
>