> -----Original Message----- > From: Justin Pryzby <pryzby@xxxxxxxxxxxxx> > Sent: Saturday, December 4, 2021 12:59 > To: ldh@xxxxxxxxxxxxxxxxxx > Cc: pgsql-performance@xxxxxxxxxxxxxx > Subject: Re: An I/O error occurred while sending to the backend (PG > 13.4) > > On Sat, Dec 04, 2021 at 05:32:10PM +0000, ldh@xxxxxxxxxxxxxxxxxx > wrote: > > I have a data warehouse with a fairly complex ETL process that has > been running for years now across PG 9.6, 11.2 and now 13.4 for the > past couple of months. I have been getting the error "An I/O error > occurred while sending to the backend" quite often under load in 13.4 > which I never used to get on 11.2. I have applied some tricks, particularly > with the socketTimeout JDBC configuration. > > > > So my first question is whether anyone has any idea why this is > happening? My hardware and general PG configuration have not > changed between 11.2 and 13.4 and I NEVER experienced this on 11.2 in > about 2y of production. > > > > Second, I have one stored procedure that takes a very long time to run > (40mn more or less), so obviously, I'd need to set socketTimeout to > something like 1h in order to call it and not timeout. That doesn't seem > reasonable? > > Is the DB server local or remote (TCP/IP) to the client? > > Could you collect the corresponding postgres query logs when this > happens ? > > It'd be nice to see a network trace for this too. Using tcpdump or > wireshark. > Preferably from the client side. > > FWIW, I suspect the JDBC socketTimeout is a bad workaround. > > -- > Justin It's a remote server, but all on a local network. Network performance is I am sure not the issue. Also, the system is on Windows Server. What are you expecting to see out of a tcpdump? I'll try to get PG logs on the failing query. Thank you, Laurent.
