Initialize subsystems before promoting

The previous patch failed, since we could not actually access the
catalog without some more initialization. Pull as much initialization
from the old Pass4 as possible -- some of it is likely not needed, but
this seems to get things working for now.

src/backend/access/transam/xlog.c

@@ -6446,6 +6446,130 @@ XLogProcessCheckpointRecord(XLogRecord *rec, XLogRecPtr loc)
 	}
 }
 
+static void
+UpdateCatalogForStandbyPromotion(void)
+{
+	/*
+	 * NOTE: The following initialization logic was borrowed from ftsprobe.
+	 */
+	SetProcessingMode(InitProcessing);
+
+	/*
+	 * Create a resource owner to keep track of our resources (currently only
+	 * buffer pins).
+	 */
+	CurrentResourceOwner = ResourceOwnerCreate(NULL, "Startup Pass 4");
+
+	/*
+	 * NOTE: AuxiliaryProcessMain has already called:
+	 * NOTE:      BaseInit,
+	 * NOTE:      InitAuxiliaryProcess instead of InitProcess, and
+	 * NOTE:      InitBufferPoolBackend.
+	 */
+
+	InitXLOGAccess();
+
+	SetProcessingMode(NormalProcessing);
+
+	/*
+	 * Add my PGPROC struct to the ProcArray.
+	 *
+	 * Once I have done this, I am visible to other backends!
+	 */
+	InitProcessPhase2();
+
+	/*
+	 * Initialize my entry in the shared-invalidation manager's array of
+	 * per-backend data.
+	 *
+	 * Sets up MyBackendId, a unique backend identifier.
+	 */
+	MyBackendId = InvalidBackendId;
+
+	/*
+	 * Though this is a startup process and currently no one sends invalidation
+	 * messages concurrently, we set sendOnly = false, since we have relcaches.
+	 */
+	SharedInvalBackendInit(false);
+
+	if (MyBackendId > MaxBackends || MyBackendId <= 0)
+			elog(FATAL, "bad backend id: %d", MyBackendId);
+
+	/*
+	 * bufmgr needs another initialization call too
+	 */
+	InitBufferPoolBackend();
+
+	/* heap access requires the rel-cache.
+	 *
+	 * Pass 2 uses heap API to insert/update/delete from persistent
+	 * tables.  In order to use the heap API, RelationDescriptor is
+	 * required.  In pass 2, persistent tables are accessed using
+	 * DirectOpen API to obtain the RelationDescriptor.  Hence, we
+	 * don't need to load full relcache as in
+	 * RelationCacheInitializePhase3().
+	 *
+	 * However, there is cache invalidation logic within heap API
+	 * needs basic data structures for catalog cache to be
+	 * initialized.  Hence, we need to do RelationCacheInitialize(),
+	 * InitCatalogCache(), and RelationCacheInitializePhase2()
+	 * before StartupXLOG_Pass2().
+	 *
+	 * Pass 4 needs RelationCacheInitializePhase3() to do catalog
+	 * validation, after xlog replay is complete.
+	 */
+	RelationCacheInitialize();
+	InitCatalogCache();
+
+	/*
+	 * It's now possible to do real access to the system catalogs.
+	 *
+	 * Load relcache entries for the system catalogs.  This must create at
+	 * least the minimum set of "nailed-in" cache entries.
+	 */
+	RelationCacheInitializePhase2();
+
+	char *fullpath;
+
+	/*
+	 * In order to access the catalog, we need a database, and a
+	 * tablespace; our access to the heap is going to be slightly
+	 * limited, so we'll just use some defaults.
+	 */
+	MyDatabaseId = TemplateDbOid;
+	MyDatabaseTableSpace = DEFAULTTABLESPACE_OID;
+
+	/*
+	 * Now we can mark our PGPROC entry with the database ID
+	 * (We assume this is an atomic store so no lock is needed)
+	 */
+	MyProc->databaseId = MyDatabaseId;
+
+	fullpath = GetDatabasePath(MyDatabaseId, MyDatabaseTableSpace);
+
+	SetDatabasePath(fullpath);
+
+	RelationCacheInitializePhase3();
+
+	/*
+	 * Now, finally, update the catalog.
+	 */
+	GpRoleValue old_role = Gp_role;
+
+	/* I am privileged */
+	InitializeSessionUserIdStandalone();
+	/* Start transaction locally */
+	Gp_role = GP_ROLE_UTILITY;
+	StartTransactionCommand();
+	GetTransactionSnapshot();
+	DirectFunctionCall1(gp_activate_standby, (Datum) 0);
+	/* close the transaction we started above */
+	CommitTransactionCommand();
+	Gp_role = old_role;
+
+	ereport(LOG, (errmsg("Updated catalog to support standby promotion")));
+}
+
 
 static void
 UpdateCatalogForStandbyPromotion(void)
@@ -7558,14 +7682,7 @@ StartupXLOG(void)
 							   true);
 #endif
 
-	/*
-	 * If we are a standby with contentid -1 and undergoing promotion,
-	 * update ourselves as the new master in catalog.  This does not
-	 * apply to a mirror (standby of a GPDB segment) because it is
-	 * managed by FTS.
-	 */
-	bool needToPromoteCatalog = (GpIdentity.segindex == MASTER_CONTENT_ID &&
-								 ControlFile->state == DB_IN_STANDBY_PROMOTED);
+	bool needToPromoteCatalog = (ControlFile->state == DB_IN_STANDBY_PROMOTED);
 
 	LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
 	ControlFile->state = DB_IN_PRODUCTION;