Init DistributedLog vars

Author: reshke

src/backend/access/transam/xlog.c

@@ -7205,6 +7205,15 @@ StartupXLOG(void)
 			/* Tell procarray about the range of xids it has to deal with */
 			ProcArrayInitRecovery(ShmemVariableCache->nextXid);
 
+			/* also initialize latestCompletedXid, to nextXid - 1 */
+			LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
+			ShmemVariableCache->latestCompletedXid = ShmemVariableCache->nextXid;
+			TransactionIdRetreat(ShmemVariableCache->latestCompletedXid);
+			elog(LOG, "latest completed transaction id is %u and next transaction id is %u",
+				ShmemVariableCache->latestCompletedXid,
+				ShmemVariableCache->nextXid);
+			LWLockRelease(ProcArrayLock);
+
 			/*
 			 * Startup commit log and subtrans only. MultiXact has already
 			 * been started up and other SLRUs are not maintained during