Index: src/backend/commands/portalcmds.c
===================================================================
RCS file: /home/alvherre/Code/cvs/pgsql/src/backend/commands/portalcmds.c,v
retrieving revision 1.79.2.1
diff -c -p -r1.79.2.1 portalcmds.c
*** src/backend/commands/portalcmds.c	2 Oct 2009 17:58:21 -0000	1.79.2.1
--- src/backend/commands/portalcmds.c	6 Oct 2009 17:10:34 -0000
*************** PerformCursorOpen(PlannedStmt *stmt, Par
*** 120,136 ****
  	}
  
  	/*
- 	 * Set up snapshot for portal.  Note that we need a fresh, independent copy
- 	 * of the snapshot because we don't want it to be modified by future
- 	 * CommandCounterIncrement calls.  We do not register it, because
- 	 * portalmem.c will take care of that internally.
- 	 */
- 	snapshot = CopySnapshot(GetActiveSnapshot());
- 
- 	/*
  	 * Start execution, inserting parameters if any.
  	 */
! 	PortalStart(portal, params, snapshot);
  
  	Assert(portal->strategy == PORTAL_ONE_SELECT);
  
--- 120,128 ----
  	}
  
  	/*
  	 * Start execution, inserting parameters if any.
  	 */
! 	PortalStart(portal, params, GetActiveSnapshot());
  
  	Assert(portal->strategy == PORTAL_ONE_SELECT);
  
Index: src/backend/utils/time/snapmgr.c
===================================================================
RCS file: /home/alvherre/Code/cvs/pgsql/src/backend/utils/time/snapmgr.c,v
retrieving revision 1.10.2.1
diff -c -p -r1.10.2.1 snapmgr.c
*** src/backend/utils/time/snapmgr.c	2 Oct 2009 17:58:21 -0000	1.10.2.1
--- src/backend/utils/time/snapmgr.c	6 Oct 2009 17:13:48 -0000
*************** bool		FirstSnapshotSet = false;
*** 104,109 ****
--- 104,110 ----
  static bool registered_serializable = false;
  
  
+ static Snapshot CopySnapshot(Snapshot snapshot);
  static void FreeSnapshot(Snapshot snapshot);
  static void SnapshotResetXmin(void);
  
*************** SnapshotSetCommandId(CommandId curcid)
*** 191,197 ****
   * The copy is palloc'd in TopTransactionContext and has initial refcounts set
   * to 0.  The returned snapshot has the copied flag set.
   */
! Snapshot
  CopySnapshot(Snapshot snapshot)
  {
  	Snapshot	newsnap;
--- 192,198 ----
   * The copy is palloc'd in TopTransactionContext and has initial refcounts set
   * to 0.  The returned snapshot has the copied flag set.
   */
! static Snapshot
  CopySnapshot(Snapshot snapshot)
  {
  	Snapshot	newsnap;
*************** FreeSnapshot(Snapshot snapshot)
*** 254,261 ****
   * PushActiveSnapshot
   *		Set the given snapshot as the current active snapshot
   *
!  * If this is the first use of this snapshot, create a new long-lived copy with
!  * active refcount=1.  Otherwise, only increment the refcount.
   */
  void
  PushActiveSnapshot(Snapshot snap)
--- 255,263 ----
   * PushActiveSnapshot
   *		Set the given snapshot as the current active snapshot
   *
!  * If the passed snapshot is a statically-allocated one, or it is possibly
!  * subject to a future command counter update, create a new long-lived copy
!  * with active refcount=1.  Otherwise, only increment the refcount.
   */
  void
  PushActiveSnapshot(Snapshot snap)
*************** PushActiveSnapshot(Snapshot snap)
*** 265,272 ****
  	Assert(snap != InvalidSnapshot);
  
  	newactive = MemoryContextAlloc(TopTransactionContext, sizeof(ActiveSnapshotElt));
! 	/* Static snapshot?  Create a persistent copy */
! 	newactive->as_snap = snap->copied ? snap : CopySnapshot(snap);
  	newactive->as_next = ActiveSnapshot;
  	newactive->as_level = GetCurrentTransactionNestLevel();
  
--- 267,278 ----
  	Assert(snap != InvalidSnapshot);
  
  	newactive = MemoryContextAlloc(TopTransactionContext, sizeof(ActiveSnapshotElt));
! 
! 	if (snap == CurrentSnapshot || snap == SecondarySnapshot || !snap->copied)
! 		newactive->as_snap = CopySnapshot(snap);
! 	else
! 		newactive->as_snap = snap;
! 
  	newactive->as_next = ActiveSnapshot;
  	newactive->as_level = GetCurrentTransactionNestLevel();
  
Index: src/include/utils/snapmgr.h
===================================================================
RCS file: /home/alvherre/Code/cvs/pgsql/src/include/utils/snapmgr.h,v
retrieving revision 1.5.2.1
diff -c -p -r1.5.2.1 snapmgr.h
*** src/include/utils/snapmgr.h	2 Oct 2009 17:58:21 -0000	1.5.2.1
--- src/include/utils/snapmgr.h	6 Oct 2009 17:13:56 -0000
*************** extern TransactionId RecentGlobalXmin;
*** 26,32 ****
  extern Snapshot GetTransactionSnapshot(void);
  extern Snapshot GetLatestSnapshot(void);
  extern void SnapshotSetCommandId(CommandId curcid);
- extern Snapshot CopySnapshot(Snapshot snapshot);
  
  extern void PushActiveSnapshot(Snapshot snapshot);
  extern void PushUpdatedSnapshot(Snapshot snapshot);
--- 26,31 ----