Fix non-wraparound xids.

Alexander Korotkov · Alexander Korotkov · commit 34015b955c5c · 2016-11-20T11:55:03.000+03:00
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
@@ -4801,6 +4801,7 @@ BootStrapXLOG(void)
 	checkPoint.PrevTimeLineID = ThisTimeLineID;
 	checkPoint.fullPageWrites = fullPageWrites;
 	checkPoint.nextXid = FirstNormalTransactionId;
+	TransactionIdAdvance(checkPoint.nextXid);
 	checkPoint.nextOid = FirstBootstrapObjectId;
 	checkPoint.nextMulti = FirstMultiXactId;
 	checkPoint.nextMultiOffset = 0;
diff --git a/src/include/access/transam.h b/src/include/access/transam.h
@@ -56,15 +56,15 @@
 #define TransactionIdAdvance(dest)	\
 	do { \
 		(dest)++; \
-		if ((dest) < FirstNormalTransactionId) \
-			(dest) = FirstNormalTransactionId; \
+		Assert((dest) > FirstNormalTransactionId); \
 	} while(0)
 
 /* back up a transaction ID variable, handling wraparound correctly */
 #define TransactionIdRetreat(dest)	\
 	do { \
+		Assert((dest) > FirstNormalTransactionId); \
 		(dest)--; \
-	} while ((dest) < FirstNormalTransactionId)
+	} while(0)
 
 /* compare two XIDs already known to be normal; this is a macro for speed */
 #define NormalTransactionIdPrecedes(id1, id2) \
