[refer #PGPRO-3213] Change way of terminating checkpointer during online upgrade

Author: knizhnik

src/backend/access/transam/xlog.c

@@ -8838,7 +8838,7 @@ CreateCheckPoint(int flags)
 	 * We now have ProcLastRecPtr = start of actual checkpoint record, recptr
 	 * = end of actual checkpoint record.
 	 */
-	if (shutdown && checkPoint.redo != ProcLastRecPtr && *OnlineUpgradePath == '\0')
+	if (shutdown && checkPoint.redo != ProcLastRecPtr)
 		ereport(PANIC,
 				(errmsg("concurrent write-ahead log activity while database system is shutting down")));
 

src/backend/port/sysv_shmem.c

@@ -870,8 +870,8 @@ PGSharedMemoryReAttach(void)
 	else
 		state = PGSharedMemoryAttach(shmid, UsedShmemSegAddr, &hdr);
 	if (state != SHMSTATE_ATTACHED)
-		elog(FATAL, "could not reattach to shared memory (key=%d, addr=%p): %m",
-			 (int) UsedShmemSegID, UsedShmemSegAddr);
+		elog(FATAL, "could not reattach to shared memory (key=%d, addr=%p, state=%d): %m",
+			 (int) UsedShmemSegID, UsedShmemSegAddr, state);
 	if (hdr != origUsedShmemSegAddr)
 		elog(FATAL, "reattaching to shared memory returned unexpected address (got %p, expected %p)",
 			 hdr, origUsedShmemSegAddr);

src/backend/postmaster/checkpointer.c

@@ -47,6 +47,7 @@
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "postmaster/bgwriter.h"
+#include "postmaster/postmaster.h"
 #include "replication/syncrep.h"
 #include "storage/bufmgr.h"
 #include "storage/condition_variable.h"
@@ -823,7 +824,13 @@ chkpt_quickdie(SIGNAL_ARGS)
 	 * should ensure the postmaster sees this as a crash, too, but no harm in
 	 * being doubly sure.)
 	 */
-	_exit(2);
+	if (*OnlineUpgradePath != '\0')
+	{
+		/* Normal exit from the checkpointer is here */
+		proc_exit(0);		/* done */
+	}
+	else
+		_exit(2);
 }
 
 /* SIGHUP: set flag to re-read config file at next convenient time */

src/backend/postmaster/postmaster.c

@@ -786,7 +786,7 @@ UpgradePostgres(void)
 	IsOnlineUpgrade = true;
 	TerminateChildren(SIGTERM);
 	if (CheckpointerPID != 0)
-		signal_child(CheckpointerPID, SIGUSR2);
+		signal_child(CheckpointerPID, SIGQUIT/*SIGUSR2*/);
 
 	if (!SavePostmasterParameters())
 	{