Connections refused during backups

Started by Glen Eustacealmost 19 years ago7 messagesgeneral
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#1Glen Eustace
geustace@godzone.net.nz

After an upgrade from 8.0.8 to 8.1.8, I am getting a number of our
scripts failing with 'connection refused' at around 4:00am, which seems
to be when the nightly database backup occurs.

I am using "/usr/bin/pg_dump -Fc -b -c -C" to do the deed.

Has there been a change in behavior, i.e. is the whole databases being
exclusively locked or something that would prevent a connection.

#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Glen Eustace (#1)
Re: Connections refused during backups

Glen Eustace <geustace@godzone.net.nz> writes:

After an upgrade from 8.0.8 to 8.1.8, I am getting a number of our
scripts failing with 'connection refused' at around 4:00am, which seems
to be when the nightly database backup occurs.

"Connection refused" is a kernel-level rejection, and at least in theory
should have nothing to do with what Postgres is doing. Did you do a
kernel update at the same time?

regards, tom lane

#3Glen Eustace
geustace@godzone.net.nz
In reply to: Tom Lane (#2)
Re: Connections refused during backups

Tom Lane wrote:

"Connection refused" is a kernel-level rejection, and at least in theory
should have nothing to do with what Postgres is doing. Did you do a
kernel update at the same time?

regards, tom lane

My apologies, I shouldn't have used the generic socket error 'Connection
refused'. What I am getting are errors like

"Could not connect to database" from libnss-pgsql

#4Tom Lane
tgl@sss.pgh.pa.us
In reply to: Glen Eustace (#3)
Re: Connections refused during backups

Glen Eustace <geustace@godzone.net.nz> writes:

My apologies, I shouldn't have used the generic socket error 'Connection
refused'. What I am getting are errors like
"Could not connect to database" from libnss-pgsql

Please be *exact* rather than handwaving. What is the full text of the
client-side message? What if anything shows up in the postmaster log?

regards, tom lane

#5Glen Eustace
geustace@godzone.net.nz
In reply to: Tom Lane (#4)
Re: Connections refused during backups

Tom Lane wrote:

Glen Eustace <geustace@godzone.net.nz> writes:

My apologies, I shouldn't have used the generic socket error 'Connection
refused'. What I am getting are errors like
"Could not connect to database" from libnss-pgsql

Please be *exact* rather than handwaving. What is the full text of the
client-side message? What if anything shows up in the postmaster log?

regards, tom lane

This is the exact message from libnss-pgsql, there is currently no
timestamp in the log ( which I will fix ), so I cannot place any
messages into the correct timeframe. I'll wait until tomorrow morning
and see if anything is obvious. The only thing I am aware of is that
nss-pgsql uses a 10s connection_timeout, which may be too short when the
pgsql server is busy.

#6Tom Lane
tgl@sss.pgh.pa.us
In reply to: Glen Eustace (#5)
Re: Connections refused during backups

Glen Eustace <geustace@godzone.net.nz> writes:

My apologies, I shouldn't have used the generic socket error 'Connection
refused'. What I am getting are errors like
"Could not connect to database" from libnss-pgsql

This is the exact message from libnss-pgsql,

While you are at it, you should complain to the libnss-pgsql authors
about the inadequacy of the error message. It should at least be
repeating the libpq error message ...

regards, tom lane

#7Glen Eustace
geustace@godzone.net.nz
In reply to: Tom Lane (#6)
Re: Connections refused during backups

Tom Lane wrote:

Glen Eustace <geustace@godzone.net.nz> writes:

My apologies, I shouldn't have used the generic socket error 'Connection
refused'. What I am getting are errors like
"Could not connect to database" from libnss-pgsql

This is the exact message from libnss-pgsql,

While you are at it, you should complain to the libnss-pgsql authors
about the inadequacy of the error message. It should at least be
repeating the libpq error message ...

regards, tom lane

Nothing of interest appears in the postmaster logs so I am broadening my
search for general network incidents/activity as opposed to postgresql
specific.

I have also downloaded the source for libnss-pgsql and will add some
extra code to see if I can get any more useful info from it.

Thanks for the comments/help to date :-)