On Wed, Jul 17, 2019 at 12:26 PM Jerry Sievers <gsiever...@comcast.net> wrote: > Is this the right sequencing? > > 1. Start client and get backend pid > 2. GDB; handle SIGUSR1, break, cont > 3. Run query > 4. bt
Perfect, thanks. I think I just spotted something: > #11 0x000055666e0359df in ExecShutdownNode (node=node@entry=0x55667033a6c8) > at > /build/postgresql-9.6-5O8OLM/postgresql-9.6-9.6.14/build/../src/backend/executor/execProcnode.c:830 > #12 0x000055666e04d0ff in ExecLimit (node=node@entry=0x55667033a428) > at > /build/postgresql-9.6-5O8OLM/postgresql-9.6-9.6.14/build/../src/backend/executor/nodeLimit.c:139 https://github.com/postgres/postgres/blob/REL9_6_STABLE/src/backend/executor/nodeLimit.c#L139 Limit thinks it's OK to "shut down" the subtree, but if you shut down a Gather node you can't rescan it later because it destroys its shared memory. Oops. Not sure what to do about that yet. -- Thomas Munro https://enterprisedb.com
