On Tue, Sep 29, 2020 at 10:01 PM Fujii Masao <masao.fu...@oss.nttdata.com> wrote: > > > I think this is okay, because pg_terminate_backend() sends SIGTERM to > > the backend, and upon receiving SIGTERM the signal handler die() will > > be called and since there is no query being executed on the backend by > > the time SIGTERM is received, it will exit immediately. Thoughts? > > Yeah, basically you're right. But that backend *can* still be running > when the subsequent test query starts. I'm wondering if wait_pid() > (please see regress.c and sql/dblink.sql) should be used to ensure > the target backend disappeared. >
I think wait_pid() is not a generic function, and I'm unable to use that inside postgres_fdw.sql. I think I need to recreate that function for postgres_fdw.sql. For dblink, it's being created as part of paths.source. Could you help me in doing so? And another way, if we don't want to use wait_pid() is to have a plpgsql stored procedure, that in a loop keeps on checking for the backed pid from pg_stat_activity, exit when pid is 0. and then proceed to issue the next foreign table query. Thoughts? mypid = -1; while (mypid != 0) SELECT pid INTO mypid FROM pg_stat_activity WHERE backend_type = 'client backend' AND application_name = 'fdw_retry_check'; With Regards, Bharath Rupireddy. EnterpriseDB: http://www.enterprisedb.com
