Hi, I was able to capture the backtrace again, now with libpq debugging symbols. Thread 15 (Thread 0x7f8cec068700 (LWP 68)): #0 0x00007f8d252a1d9b in __libc_recv (fd=150, buf=0x7f8cf0034410, n=16384, flags=623517083, flags@entry=0) at ../sysdeps/unix/sysv/linux/x86_64/recv.c:33 #1 0x00007f8d26689783 in recv (__flags=0, __n=<optimized out>, __buf=<optimized out>, __fd=<optimized out>) at /usr/include/x86_64-linux-gnu/bits/socket2.h:44 #2 pqsecure_raw_read (conn=conn@entry=0x7f8cf001e390, ptr=<optimized out>, len=<optimized out>) at /build/postgresql-10-rIfDLC/postgresql-10-10.2/build/../src/interfaces/libpq/fe-secure.c:230 #3 0x00007f8d26689863 in pqsecure_read (conn=conn@entry=0x7f8cf001e390, ptr=<optimized out>, len=<optimized out>) at /build/postgresql-10-rIfDLC/postgresql-10-10.2/build/../src/interfaces/libpq/fe-secure.c:217 #4 0x00007f8d266810ea in pqReadData (conn=conn@entry=0x7f8cf001e390) at /build/postgresql-10-rIfDLC/postgresql-10-10.2/build/../src/interfaces/libpq/fe-misc.c:683 #5 0x00007f8d2667e6f2 in PQconsumeInput (conn=0x7f8cf001e390) at /build/postgresql-10-rIfDLC/postgresql-10-10.2/build/../src/interfaces/libpq/fe-exec.c:1704 In this case, I also checked the pg_stat_activity and this particular connection on pg server side was idle for 15 minutes. I killed it using pg_terminate_backend, and then somehow the application resumed execution. As you can see, recv has received a non-zero value in flags, which has the MSG_WAITALL bit is set, however in this case the application expects the read to be non-blocking. Thanks in advance, André Freitas 2018-02-23 16:10 GMT-03:00 Andres Freund <andres@xxxxxxxxxxx>: > Hi, > > On 2018-02-23 15:59:18 -0300, Andre Oliveira Freitas wrote: >> I'm using the libpq that comes with debian, however I can install the >> library from the official repository to be sure, I assume the one from >> the official repo has it enabled. > > That should be fine. Could you get the backtrace again, after installing > debugging symbols? It'd certainly be helpful to see the exact path to > the blocking syscall. > > Greetings, > > Andres Freund -- André Luis O. Freitas System Architect Rua do Rócio, 220 - Cj. 72 São Paulo - SP - 04552-000 55 11 4063 4222 afreitas@xxxxxxxxxxxxx www.callix.com.br
