Hi Noah, below is the output from one of the servers having this issue: $ echo "select pg_backend_pid(); load 'dblink'; select pg_sleep(100)" | psql -X & [1] 9731
$ select pg_backend_pid(); load 'dblink'; select pg_sleep(100) pg_backend_pid ---------------- 9732 (1 row) LOAD $ gdb --batch --pid 9732 -ex 'info sharedlibrary ldap' warning: .dynamic section for "/lib64/libldap-2.4.so.2" is not at the expected address (wrong library or version mismatch?) warning: .dynamic section for "/lib64/liblber-2.4.so.2" is not at the expected address (wrong library or version mismatch?) [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib64/libthread_db.so.1". 0x00007f1e7592dcf3 in __epoll_wait_nocancel () from /lib64/libc.so.6 >From To Syms Read Shared Object Library 0x00007f1e7637d0f8 0x00007f1e763ae51c Yes (*) /lib64/libldap-2.4.so.2 0x00007f1d9f2c16d0 0x00007f1d9f2f5ae4 Yes (*) /lib64/libldap_r-2.4.so.2 (*): Shared library is missing debugging information. Regards, Mike Yeap On Thu, Mar 14, 2019 at 1:42 PM Noah Misch <n...@leadboat.com> wrote: > On Thu, Mar 14, 2019 at 05:18:49PM +1300, Thomas Munro wrote: > > On Thu, Mar 7, 2019 at 4:19 PM Noah Misch <n...@leadboat.com> wrote: > > > Has anyone else reproduced this? > > > > I tried, but could not reproduce this problem on "CentOS Linux release > > 7.6.1810 (Core)" using OpenLDAP "2.4.44-21.el7_6" (same as Mike > > reported, what yum install is currently serving up). > > > When exiting the session, I was expecting the backend to crash, > > because it had executed libldap.so code during authentication, and > > then it had linked in libldap_r.so via libpq.so while connecting via > > postgres_fdw. But it doesn't crash. I wonder what is different for > > Mike; am I missing something, or is there non-determinism here? > > The test is deterministic. I'm guessing Mike's system is finding ldap > libraries other than the usual system ones. Mike, would you check as > follows? > > $ echo "select pg_backend_pid(); load 'dblink'; select pg_sleep(100)" | > psql -X & > [1] 2530123 > pg_backend_pid > ---------------- > 2530124 > (1 row) > > LOAD > > $ gdb --batch --pid 2530124 -ex 'info sharedlibrary ldap' > [Thread debugging using libthread_db enabled] > Using host libthread_db library "/lib64/libthread_db.so.1". > 0x00007ffff6303463 in __epoll_wait_nocancel () from /lib64/libc.so.6 > From To Syms Read Shared Object Library > 0x00007ffff65e1ee0 0x00007ffff6613304 Yes (*) /lib64/libldap-2.4.so.2 > 0x00007fffe998f6d0 0x00007fffe99c3ae4 Yes (*) > /lib64/libldap_r-2.4.so.2 > (*): Shared library is missing debugging information. >