Clean up properly error_context_stack in autovacuum worker on exception

Any callback set would have no meaning in the context of an exception.
As an autovacuum worker exits quickly in this context, this could be
only an issue within EmitErrorReport(), where the elog hook is for
example called.  That's unlikely to going to be a problem, but let's be
clean and consistent with other code paths handling exceptions.  This is
present since 2909419, which introduced autovacuum.

Author: Ashwin Agrawal
Reviewed-by: Tom Lane, Michael Paquier
Discussion: https://postgr.es/m/CALfoeisM+_+dgmAdAOHAu0k-ZpEHHqSSG=GRf3pKJGm8OqWX0w@mail.gmail.com
Backpatch-through: 9.4

diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 073f313337d4964df1273706f039e6ae4ec83897..c1dd8168cafc3e101e33e4efa5555f64c3d13afe 100644 (file)
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -1558,6 +1558,9 @@ AutoVacWorkerMain(int argc, char *argv[])
         */
        if (sigsetjmp(local_sigjmp_buf, 1) != 0)
        {
+               /* since not using PG_TRY, must reset error stack by hand */
+               error_context_stack = NULL;
+
                /* Prevents interrupts while cleaning up */
                HOLD_INTERRUPTS();