diff --git a/doc/src/sgml/bgworker.sgml b/doc/src/sgml/bgworker.sgml
index 7fd673ab54e..d34acfc220d 100644
--- a/doc/src/sgml/bgworker.sgml
+++ b/doc/src/sgml/bgworker.sgml
@@ -11,8 +11,8 @@
   PostgreSQL can be extended to run user-supplied code in separate processes.
   Such processes are started, stopped and monitored by <command>postgres</command>,
   which permits them to have a lifetime closely linked to the server's status.
-  These processes have the option to attach to <productname>PostgreSQL</productname>'s
-  shared memory area and to connect to databases internally; they can also run
+  These processes are attached to <productname>PostgreSQL</productname>'s
+  shared memory area and have the option to connect to databases internally; they can also run
   multiple transactions serially, just like a regular client-connected server
   process.  Also, by linking to <application>libpq</application> they can connect to the
   server and behave like a regular client application.
@@ -89,11 +89,7 @@ typedef struct BackgroundWorker
      <listitem>
       <para>
        <indexterm><primary>BGWORKER_SHMEM_ACCESS</primary></indexterm>
-       Requests shared memory access.  Workers without shared memory access
-       cannot access any of <productname>PostgreSQL's</productname> shared
-       data structures, such as heavyweight or lightweight locks, shared
-       buffers, or any custom data structures which the worker itself may
-       wish to create and use.
+       Requests shared memory access.  This flag is required.
       </para>
      </listitem>
     </varlistentry>
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 11c4ceddbf6..c05f5006393 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -652,17 +652,24 @@ static bool
 SanityCheckBackgroundWorker(BackgroundWorker *worker, int elevel)
 {
 	/* sanity check for flags */
+
+	/*
+	 * We used to support workers not connected to shared memory, but don't
+	 * anymore. Thus this is a required flag now. We're not removing the flag
+	 * for compatibility reasons and because the flag still provides some
+	 * signal when reading code.
+	 */
+	if (!(worker->bgw_flags & BGWORKER_SHMEM_ACCESS))
+	{
+		ereport(elevel,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("background worker \"%s\": background worker without shared memory access are not supported",
+						worker->bgw_name)));
+		return false;
+	}
+
 	if (worker->bgw_flags & BGWORKER_BACKEND_DATABASE_CONNECTION)
 	{
-		if (!(worker->bgw_flags & BGWORKER_SHMEM_ACCESS))
-		{
-			ereport(elevel,
-					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-					 errmsg("background worker \"%s\": must attach to shared memory in order to request a database connection",
-							worker->bgw_name)));
-			return false;
-		}
-
 		if (worker->bgw_start_time == BgWorkerStart_PostmasterStart)
 		{
 			ereport(elevel,
@@ -745,20 +752,6 @@ StartBackgroundWorker(void)
 	MyBackendType = B_BG_WORKER;
 	init_ps_display(worker->bgw_name);
 
-	/*
-	 * If we're not supposed to have shared memory access, then detach from
-	 * shared memory.  If we didn't request shared memory access, the
-	 * postmaster won't force a cluster-wide restart if we exit unexpectedly,
-	 * so we'd better make sure that we don't mess anything up that would
-	 * require that sort of cleanup.
-	 */
-	if ((worker->bgw_flags & BGWORKER_SHMEM_ACCESS) == 0)
-	{
-		ShutdownLatchSupport();
-		dsm_detach_all();
-		PGSharedMemoryDetach();
-	}
-
 	SetProcessingMode(InitProcessing);
 
 	/* Apply PostAuthDelay */
@@ -832,29 +825,19 @@ StartBackgroundWorker(void)
 	PG_exception_stack = &local_sigjmp_buf;
 
 	/*
-	 * If the background worker request shared memory access, set that up now;
-	 * else, detach all shared memory segments.
+	 * Create a per-backend PGPROC struct in shared memory, except in the
+	 * EXEC_BACKEND case where this was done in SubPostmasterMain. We must
+	 * do this before we can use LWLocks (and in the EXEC_BACKEND case we
+	 * already had to do some stuff with LWLocks).
 	 */
-	if (worker->bgw_flags & BGWORKER_SHMEM_ACCESS)
-	{
-		/*
-		 * Create a per-backend PGPROC struct in shared memory, except in the
-		 * EXEC_BACKEND case where this was done in SubPostmasterMain. We must
-		 * do this before we can use LWLocks (and in the EXEC_BACKEND case we
-		 * already had to do some stuff with LWLocks).
-		 */
 #ifndef EXEC_BACKEND
-		InitProcess();
+	InitProcess();
 #endif
 
-		/*
-		 * Early initialization.  Some of this could be useful even for
-		 * background workers that aren't using shared memory, but they can
-		 * call the individual startup routines for those subsystems if
-		 * needed.
-		 */
-		BaseInit();
-	}
+	/*
+	 * Early initialization.
+	 */
+	BaseInit();
 
 	/*
 	 * Look up the entry point function, loading its library if necessary.
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index fc0bc8d99ee..9c2c98614aa 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -3302,26 +3302,21 @@ CleanupBackgroundWorker(int pid,
 		}
 
 		/*
-		 * Additionally, for shared-memory-connected workers, just like a
-		 * backend, any exit status other than 0 or 1 is considered a crash
-		 * and causes a system-wide restart.
+		 * Additionally, just like a backend, any exit status other than 0 or
+		 * 1 is considered a crash and causes a system-wide restart.
 		 */
-		if ((rw->rw_worker.bgw_flags & BGWORKER_SHMEM_ACCESS) != 0)
+		if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
 		{
-			if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
-			{
-				HandleChildCrash(pid, exitstatus, namebuf);
-				return true;
-			}
+			HandleChildCrash(pid, exitstatus, namebuf);
+			return true;
 		}
 
 		/*
-		 * We must release the postmaster child slot whether this worker is
-		 * connected to shared memory or not, but we only treat it as a crash
-		 * if it is in fact connected.
+		 * We must release the postmaster child slot. If the worker failed to
+		 * do so, it did not clean up after itself, requiring a crash-restart
+		 * cycle.
 		 */
-		if (!ReleasePostmasterChildSlot(rw->rw_child_slot) &&
-			(rw->rw_worker.bgw_flags & BGWORKER_SHMEM_ACCESS) != 0)
+		if (!ReleasePostmasterChildSlot(rw->rw_child_slot))
 		{
 			HandleChildCrash(pid, exitstatus, namebuf);
 			return true;
diff --git a/src/include/postmaster/bgworker.h b/src/include/postmaster/bgworker.h
index 8e9ef7c7bfa..6d4122b4c7e 100644
--- a/src/include/postmaster/bgworker.h
+++ b/src/include/postmaster/bgworker.h
@@ -48,6 +48,7 @@
 
 /*
  * Pass this flag to have your worker be able to connect to shared memory.
+ * This flag is required.
  */
 #define BGWORKER_SHMEM_ACCESS						0x0001