1 files changed, 26 insertions, 12 deletions

diff --git a/src/backend/utils/adt/mcxtfuncs.c b/src/backend/utils/adt/mcxtfuncs.c
index 845d619d605..28cb9d3ff10 100644
--- a/src/backend/utils/adt/mcxtfuncs.c
+++ b/src/backend/utils/adt/mcxtfuncs.c
@@ -160,33 +160,47 @@ pg_get_backend_memory_contexts(PG_FUNCTION_ARGS)
 
 /*
  * pg_log_backend_memory_contexts
- *		Signal a backend process to log its memory contexts.
+ *		Signal a backend or an auxiliary process to log its memory contexts.
  *
  * By default, only superusers are allowed to signal to log the memory
  * contexts because allowing any users to issue this request at an unbounded
  * rate would cause lots of log messages and which can lead to denial of
  * service. Additional roles can be permitted with GRANT.
  *
- * On receipt of this signal, a backend sets the flag in the signal
- * handler, which causes the next CHECK_FOR_INTERRUPTS() to log the
- * memory contexts.
+ * On receipt of this signal, a backend or an auxiliary process sets the flag
+ * in the signal handler, which causes the next CHECK_FOR_INTERRUPTS()
+ * or process-specific interrupt handler to log the memory contexts.
  */
 Datum
 pg_log_backend_memory_contexts(PG_FUNCTION_ARGS)
 {
 	int			pid = PG_GETARG_INT32(0);
 	PGPROC	   *proc;
+	BackendId	backendId = InvalidBackendId;
 
 	proc = BackendPidGetProc(pid);
 
 	/*
-	 * BackendPidGetProc returns NULL if the pid isn't valid; but by the time
-	 * we reach kill(), a process for which we get a valid proc here might
-	 * have terminated on its own.  There's no way to acquire a lock on an
-	 * arbitrary process to prevent that. But since this mechanism is usually
-	 * used to debug a backend running and consuming lots of memory, that it
-	 * might end on its own first and its memory contexts are not logged is
-	 * not a problem.
+	 * See if the process with given pid is a backend or an auxiliary process.
+	 *
+	 * If the given process is a backend, use its backend id in
+	 * SendProcSignal() later to speed up the operation. Otherwise, don't do
+	 * that because auxiliary processes (except the startup process) don't
+	 * have a valid backend id.
+	 */
+	if (proc != NULL)
+		backendId = proc->backendId;
+	else
+		proc = AuxiliaryPidGetProc(pid);
+
+	/*
+	 * BackendPidGetProc() and AuxiliaryPidGetProc() return NULL if the pid
+	 * isn't valid; but by the time we reach kill(), a process for which we
+	 * get a valid proc here might have terminated on its own.  There's no way
+	 * to acquire a lock on an arbitrary process to prevent that. But since
+	 * this mechanism is usually used to debug a backend or an auxiliary
+	 * process running and consuming lots of memory, that it might end on its
+	 * own first and its memory contexts are not logged is not a problem.
 	 */
 	if (proc == NULL)
 	{
@@ -199,7 +213,7 @@ pg_log_backend_memory_contexts(PG_FUNCTION_ARGS)
 		PG_RETURN_BOOL(false);
 	}
 
-	if (SendProcSignal(pid, PROCSIG_LOG_MEMORY_CONTEXT, proc->backendId) < 0)
+	if (SendProcSignal(pid, PROCSIG_LOG_MEMORY_CONTEXT, backendId) < 0)
 	{
 		/* Again, just a warning to allow loops */
 		ereport(WARNING,