@@ -251,6 +251,12 @@ static Snapshot DtmCopySnapshot(Snapshot snapshot)
251251static Snapshot DtmGetSnapshot ()
252252{
253253CurrentTransactionSnapshot = GetLocalTransactionSnapshot ();
254+ if (DtmGlobalTransaction && !IsolationUsesXactSnapshot ()){/* RU & RC */
255+ DtmEnsureConnection ();
256+ DtmGlobalGetSnapshot (DtmConn ,DtmNodeId ,GetCurrentTransactionId (),& DtmSnapshot );
257+ DtmMergeSnapshots (CurrentTransactionSnapshot ,& DtmSnapshot );
258+ DtmUpdateRecentXmin ();
259+ }
254260return CurrentTransactionSnapshot ;
255261}
256262
@@ -438,16 +444,20 @@ dtm_begin_transaction(PG_FUNCTION_ARGS)
438444gtid .nNodes = ArrayGetNItems (ARR_NDIM (nodes ),ARR_DIMS (nodes ));
439445DtmGlobalTransaction = true;
440446Assert (gtid .xids [DtmNodeId ]== GetCurrentTransactionId ());
441- XTM_INFO ("Start transaction {%d,%d} at node %d\n" ,gtid .xids [0 ],gtid .xids [1 ],DtmNodeId );
447+ XTM_INFO ("Start transaction {%d,%d} at node %d, iso=%d \n" ,gtid .xids [0 ],gtid .xids [1 ],DtmNodeId , XactIsoLevel );
442448if (DtmNodeId == gtid .nodes [0 ]) {
443449DtmEnsureConnection ();
444450DtmGlobalStartTransaction (DtmConn ,& gtid );
445451 }
446- DtmEnsureConnection ();
447- DtmGlobalGetSnapshot (DtmConn ,DtmNodeId ,gtid .xids [DtmNodeId ],& DtmSnapshot );
448- Assert (CurrentTransactionSnapshot != NULL );
449- DtmMergeSnapshots (CurrentTransactionSnapshot ,& DtmSnapshot );
450- DtmUpdateRecentXmin ();
452+
453+ if (IsolationUsesXactSnapshot ()){/* RR & S */
454+ DtmEnsureConnection ();
455+ DtmGlobalGetSnapshot (DtmConn ,DtmNodeId ,gtid .xids [DtmNodeId ],& DtmSnapshot );
456+ Assert (CurrentTransactionSnapshot != NULL );
457+ DtmMergeSnapshots (CurrentTransactionSnapshot ,& DtmSnapshot );
458+ DtmUpdateRecentXmin ();
459+ }
460+
451461PG_RETURN_VOID ();
452462}
453463