On 12/28/2011 09:34 AM, Alvaro Herrera wrote:
Excerpts from Steve Crawford's message of mié dic 28 13:24:37 -0300 2011:
On 12/28/2011 05:05 AM, Alvaro Herrera wrote:
Excerpts from Steve Crawford's message of mar dic 27 22:51:06 -0300 2011:
I have a system (9.0.4 on Ubuntu Server 10.04 LTS x86_64) that is
currently in test/dev mode. I'm currently seeing the following messages
occurring every few seconds:
...
Dec 27 17:43:22 foo postgres[23693]: [6-1] : WARNING: pgstat wait timeout
Dec 27 17:43:27 foo postgres[27324]: [71400-1] : WARNING: pgstat wait
timeout
Dec 27 17:43:33 foo postgres[23695]: [6-1] : WARNING: pgstat wait timeout
Dec 27 17:43:54 foo postgres[27324]: [71401-1] : WARNING: pgstat wait
timeout
Hm, so can you strace the stats collector to see what it's doing? Maybe
grab a backtrace with GDB from it before anything else.
My guess is 27324 is the autovac launcher and the others are autovac
workers just as they die.
You are correct. 27324 is the launcher and the others are autovac
workers. Here's the strace of the stats collector process:
getppid() = 27320
poll([{fd=8, events=POLLIN|POLLERR}], 1, 2000) = 0 (Timeout)
getppid() = 27320
poll([{fd=8, events=POLLIN|POLLERR}], 1, 2000) = 0 (Timeout)
getppid() = 27320
poll([{fd=8, events=POLLIN|POLLERR}], 1, 2000) = 0 (Timeout)
....rinse...lather...repeat...ad nauseum...
Weird ... even across more "pgstat wait timeout" messages? It's like
it's not getting the "inquiry" messages that would tell it to write the
file ... something wrong with the UDP socket perhaps?
Bingo!
postgres 27325 postgres 8u *IPv6* 5379428
0t0 UDP localhost:47204->localhost:47204
In working on diagnosing a network timeout issue over an IPv4 to IPv4
VPN I disabled IPv6 via sysctl on this machine and pretty much forgot
about it since we are still IPv4 internally. But PostgreSQL had already
established a (now non-functional) IPv6 local connection. Re-enabling
IPv6, as it was not related to the VPN timeouts, corrected the "pgstat
wait timeout" issue.
Cheers,
Steve
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