postgrespro
diff --git a/‎contrib/pg_xtm/README
Lines changed: 15 additions & 7 deletions b/‎contrib/pg_xtm/README
Lines changed: 15 additions & 7 deletions
@@ -38,23 +38,31 @@ libdtm api
 
 void DtmInitSnapshot(Snapshot snapshot);
 
-// Starts new global transaction
-TransactionId DtmGlobalStartTransaction(int nParticipants, Snapshot shaposhot);
+// Starts a new global transaction of nParticipants size. Returns the
+// transaction id and fills the snapshot on success. Returns INVALID_XID
+// otherwise.
+TransactionId DtmGlobalStartTransaction(int nParticipants, Snapshot shapshot);
 
-// Get existed DTM snapshot.
+// Asks the DTM for a fresh snapshot.
 void DtmGlobalGetSnapshot(TransactionId xid, Snapshot snapshot);
 
 // Commits transaction only once all participants have called this function,
-// does not change CLOG otherwise.
-void DtmGlobalSetTransStatus(TransactionId xid, XidStatus status, bool wait);
+// does not change CLOG otherwise. Set 'wait' to 'true' if you want this call
+// to return only after the transaction is considered finished by the DTM.
+// Returns the status on success, or -1 otherwise.
+XidStatus DtmGlobalSetTransStatus(TransactionId xid, XidStatus status, bool wait);
 
 // Gets the status of the transaction identified by 'xid'. Returns the status
 // on success, or -1 otherwise. If 'wait' is true, then it does not return
 // until the transaction is finished.
 XidStatus DtmGlobalGetTransStatus(TransactionId xid, bool wait);
 
-// Reserve XIDs for local transaction
-TransactioinId DtmGlobalReserve(int nXids);
+// Reserves at least 'nXids' successive xids for local transactions. The xids
+// reserved are not less than 'xid' in value. Returns the actual number
+// of xids reserved, and sets the 'first' xid accordingly. The number of xids
+// reserved is guaranteed to be at least nXids.
+// In other words, *first ≥ xid and result ≥ nXids.
+int DtmGlobalReserve(TransactionId xid, int nXids, TransactionId *first);
 
 --------------------
 Backend-DTM Protocol