| From: | Craig Ringer <craig(at)postnewspapers(dot)com(dot)au> |
|---|---|
| To: | Dmitri Girski <mitek17(at)gmail(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: pg_connect takes 3.0 seconds |
| Date: | 2010-01-07 07:40:00 |
| Message-ID: | 4B458FD0.8020205@postnewspapers.com.au |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
On 7/01/2010 10:44 AM, Dmitri Girski wrote:
> Hi everybody,
>
> Many thanks to everyone replied, I think we are on the right way.
> I've used tcpdump to generate the logs and there are a lot of dropped
> packets due to the bad checksum. Network guy is currently looking at the
> problem and most likely this is hardware issue.
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
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