Postgres95 1.01 Distribution - Virgin Sources

src/backend/utils/time/Makefile.inc

@@ -0,0 +1,14 @@
+#-------------------------------------------------------------------------
+#
+# Makefile.inc--
+#    Makefile for utils/time
+#
+# Copyright (c) 1994, Regents of the University of California
+#
+#
+# IDENTIFICATION
+#    $Header: /cvsroot/pgsql/src/backend/utils/time/Attic/Makefile.inc,v 1.1.1.1 1996/07/09 06:22:10 scrappy Exp $
+#
+#-------------------------------------------------------------------------
+
+SUBSRCS+= tqual.c

src/backend/utils/time/tqual.c

@@ -0,0 +1,815 @@
+/*-------------------------------------------------------------------------
+ *
+ * tqual.c--
+ *    POSTGRES time qualification code.
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *    $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.1.1.1 1996/07/09 06:22:10 scrappy Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/* #define TQUALDEBUG	1 */
+
+#include "postgres.h"
+
+#include "access/htup.h"
+#include "access/xact.h"
+#include "storage/bufmgr.h"
+#include "access/transam.h"
+#include "utils/elog.h"
+#include "utils/palloc.h"
+#include "utils/nabstime.h"
+
+#include "utils/tqual.h"
+
+/*
+ * TimeQualMode --
+ *	Mode indicator for treatment of time qualifications.
+ */
+typedef uint16	TimeQualMode;
+
+#define TimeQualAt	0x1
+#define TimeQualNewer	0x2
+#define TimeQualOlder	0x4
+#define TimeQualAll	0x8
+
+#define TimeQualMask	0xf
+
+#define TimeQualEvery	0x0
+#define TimeQualRange	(TimeQualNewer | TimeQualOlder)
+#define TimeQualAllAt	(TimeQualAt | TimeQualAll)
+
+typedef struct TimeQualData {
+    AbsoluteTime	start;
+    AbsoluteTime	end;
+    TimeQualMode	mode;
+} TimeQualData;
+
+typedef TimeQualData	*InternalTimeQual;
+
+static TimeQualData	SelfTimeQualData;
+TimeQual		SelfTimeQual = (Pointer)&SelfTimeQualData;
+
+extern bool		PostgresIsInitialized;
+
+/*
+ * XXX Transaction system override hacks start here
+ */
+#ifndef	GOODAMI
+
+static TransactionId	HeapSpecialTransactionId = InvalidTransactionId;
+static CommandId	HeapSpecialCommandId = FirstCommandId;
+
+void
+setheapoverride(bool on)
+{
+    if (on) {
+	TransactionIdStore(GetCurrentTransactionId(),
+			   &HeapSpecialTransactionId);
+	HeapSpecialCommandId = GetCurrentCommandId();
+    } else {
+	HeapSpecialTransactionId = InvalidTransactionId;
+    }
+}
+
+/* static */
+bool
+heapisoverride()
+{
+    if (!TransactionIdIsValid(HeapSpecialTransactionId)) {
+	return (false);
+    }
+    
+    if (!TransactionIdEquals(GetCurrentTransactionId(),
+			     HeapSpecialTransactionId) ||
+	GetCurrentCommandId() != HeapSpecialCommandId) {
+	HeapSpecialTransactionId = InvalidTransactionId;
+	
+	return (false);
+    }
+    return (true);
+}
+
+#endif	/* !defined(GOODAMI) */
+/*
+ * XXX Transaction system override hacks end here
+ */
+
+static bool HeapTupleSatisfiesItself(HeapTuple tuple);
+static bool HeapTupleSatisfiesNow(HeapTuple tuple);
+static bool HeapTupleSatisfiesSnapshotInternalTimeQual(HeapTuple tuple,
+					   InternalTimeQual qual);
+static bool HeapTupleSatisfiesUpperBoundedInternalTimeQual(HeapTuple tuple,
+					       InternalTimeQual qual);
+static bool HeapTupleSatisfiesUpperUnboundedInternalTimeQual(HeapTuple tuple,
+						 InternalTimeQual qual);
+
+
+     
+/*
+ * TimeQualIsValid --
+ *	True iff time qualification is valid.
+ */
+bool
+TimeQualIsValid(TimeQual qual)
+{
+    bool	hasStartTime;
+    
+    if (!PointerIsValid(qual) || qual == SelfTimeQual) {
+	return (true);
+    }
+    
+    if (((InternalTimeQual)qual)->mode & ~TimeQualMask) {
+	return (false);
+    }
+    
+    if (((InternalTimeQual)qual)->mode & TimeQualAt) {
+	return (AbsoluteTimeIsBackwardCompatiblyValid(((InternalTimeQual)qual)->start));
+    }
+    
+    hasStartTime = false;
+    
+    if (((InternalTimeQual)qual)->mode & TimeQualNewer) {
+	if (!AbsoluteTimeIsBackwardCompatiblyValid(((InternalTimeQual)qual)->start)) {
+	    return (false);
+	}
+	hasStartTime = true;
+    }
+    
+    if (((InternalTimeQual)qual)->mode & TimeQualOlder) {
+	if (!AbsoluteTimeIsBackwardCompatiblyValid(((InternalTimeQual)qual)->end)) {
+	    return (false);
+	}
+	if (hasStartTime) {
+	    return ((bool)!AbsoluteTimeIsBefore(
+						((InternalTimeQual)qual)->end,
+						((InternalTimeQual)qual)->start));
+	}
+    }
+    return (true);
+}
+
+/*
+ * TimeQualIsLegal --
+ *	True iff time qualification is legal.
+ *	I.e., true iff time qualification does not intersects the future,
+ *	relative to the transaction start time.
+ *
+ * Note:
+ *	Assumes time qualification is valid.
+ */
+bool
+TimeQualIsLegal(TimeQual qual)
+{
+    Assert(TimeQualIsValid(qual));
+    
+    if (qual == NowTimeQual || qual == SelfTimeQual) {
+	return (true);
+    }
+    
+    /* TimeQualAt */
+    if (((InternalTimeQual)qual)->mode & TimeQualAt) {
+	AbsoluteTime a, b;
+	
+	a = ((InternalTimeQual)qual)->start;
+	b = GetCurrentTransactionStartTime();
+	
+	if (AbsoluteTimeIsAfter(a, b))
+	    return (false);
+	else
+	    return (true);
+    }
+    
+    /* TimeQualOlder or TimeQualRange */
+    if (((InternalTimeQual)qual)->mode & TimeQualOlder) {
+	AbsoluteTime a, b;
+	
+	a = ((InternalTimeQual)qual)->end;
+	b = GetCurrentTransactionStartTime();
+	
+	if (AbsoluteTimeIsAfter(a, b))
+	    return (false);
+	else
+	    return (true);
+    }
+    
+    /* TimeQualNewer */
+    if (((InternalTimeQual)qual)->mode & TimeQualNewer) {
+	AbsoluteTime a, b;
+	
+	a = ((InternalTimeQual)qual)->start;
+	b = GetCurrentTransactionStartTime();
+	
+	if (AbsoluteTimeIsAfter(a, b))
+	    return (false);
+	else
+	    return (true);
+    }
+    
+    /* TimeQualEvery */
+    return (true);
+}
+
+/*
+ * TimeQualIncludesNow --
+ *	True iff time qualification includes "now."
+ *
+ * Note:
+ *	Assumes time qualification is valid.
+ */
+bool
+TimeQualIncludesNow(TimeQual qual)
+{
+    Assert(TimeQualIsValid(qual));
+    
+    if (qual == NowTimeQual || qual == SelfTimeQual) {
+	return (true);
+    }
+    
+    if (((InternalTimeQual)qual)->mode & TimeQualAt) {
+	return (false);
+    }
+    if (((InternalTimeQual)qual)->mode & TimeQualOlder &&
+	!AbsoluteTimeIsAfter(
+			     ((InternalTimeQual)qual)->end,
+			     GetCurrentTransactionStartTime())) {
+	
+	return (false);
+    }
+    return (true);
+}
+
+/*
+ * TimeQualIncludesPast --
+ *	True iff time qualification includes some time in the past.
+ *
+ * Note:
+ *	Assumes time qualification is valid.
+ *	XXX may not be needed?
+ */
+bool
+TimeQualIncludesPast(TimeQual qual)
+{
+    Assert(TimeQualIsValid(qual));
+    
+    if (qual == NowTimeQual || qual == SelfTimeQual) {
+	return (false);
+    }
+    
+    /* otherwise, must check archive (setting locks as appropriate) */
+    return (true);
+}
+
+/*
+ * TimeQualIsSnapshot --
+ *	True iff time qualification is a snapshot qualification.
+ *
+ * Note:
+ *	Assumes time qualification is valid.
+ */
+bool
+TimeQualIsSnapshot(TimeQual qual)
+{
+    Assert(TimeQualIsValid(qual));
+    
+    if (qual == NowTimeQual || qual == SelfTimeQual) {
+	return (false);
+    }
+    
+    return ((bool)!!(((InternalTimeQual)qual)->mode & TimeQualAt));
+}
+
+/*
+ * TimeQualIsRanged --
+ *	True iff time qualification is a ranged qualification.
+ *
+ * Note:
+ *	Assumes time qualification is valid.
+ */
+bool
+TimeQualIsRanged(TimeQual qual)
+{
+    Assert(TimeQualIsValid(qual));
+    
+    if (qual == NowTimeQual || qual == SelfTimeQual) {
+	return (false);
+    }
+    
+    return ((bool)!(((InternalTimeQual)qual)->mode & TimeQualAt));
+}
+
+/*
+ * TimeQualIndicatesDisableValidityChecking --
+ *	True iff time qualification indicates validity checking should be
+ *	disabled.
+ *
+ * Note:
+ *	XXX This should not be implemented since this does not make sense.
+ */
+bool
+TimeQualIndicatesDisableValidityChecking(TimeQual qual)
+{
+    Assert (TimeQualIsValid(qual));
+    
+    if (qual == NowTimeQual || qual == SelfTimeQual) {
+	return (false);
+    }
+    
+    if (((InternalTimeQual)qual)->mode & TimeQualAll) {
+	return (true);
+    }
+    return (false);
+}
+
+/*
+ * TimeQualGetSnapshotTime --
+ *	Returns time for a snapshot time qual.
+ *
+ * Note:
+ *	Assumes time qual is valid snapshot time qual.
+ */
+AbsoluteTime
+TimeQualGetSnapshotTime(TimeQual qual)
+{
+    Assert(TimeQualIsSnapshot(qual));
+    
+    return (((InternalTimeQual)qual)->start);
+}
+
+/*
+ * TimeQualGetStartTime --
+ *	Returns start time for a ranged time qual.
+ *
+ * Note:
+ *	Assumes time qual is valid ranged time qual.
+ */
+AbsoluteTime
+TimeQualGetStartTime(TimeQual qual)
+{
+    Assert(TimeQualIsRanged(qual));
+    
+    return (((InternalTimeQual)qual)->start);
+}
+
+/*
+ * TimeQualGetEndTime --
+ *	Returns end time for a ranged time qual.
+ *
+ * Note:
+ *	Assumes time qual is valid ranged time qual.
+ */
+AbsoluteTime
+TimeQualGetEndTime(TimeQual qual)
+{
+    Assert(TimeQualIsRanged(qual));
+    
+    return (((InternalTimeQual)qual)->end);
+}
+
+/*
+ * TimeFormSnapshotTimeQual --
+ *	Returns snapshot time qual for a time.
+ *
+ * Note:
+ *	Assumes time is valid.
+ */
+TimeQual
+TimeFormSnapshotTimeQual(AbsoluteTime time)
+{
+    InternalTimeQual	qual;
+    
+    Assert(AbsoluteTimeIsBackwardCompatiblyValid(time));
+    
+    qual = (InternalTimeQual)palloc(sizeof *qual);
+    
+    qual->start = time;
+    qual->end = INVALID_ABSTIME;
+    qual->mode = TimeQualAt;
+    
+    return ((TimeQual)qual);
+}
+
+/*
+ * TimeFormRangedTimeQual --
+ *	Returns ranged time qual for a pair of times.
+ *
+ * Note:
+ *	If start time is invalid, it is regarded as the epoch.
+ *	If end time is invalid, it is regarded as "now."
+ *	Assumes start time is before (or the same as) end time.
+ */
+TimeQual
+TimeFormRangedTimeQual(AbsoluteTime startTime,
+		       AbsoluteTime endTime)
+{
+    InternalTimeQual	qual;
+    
+    qual = (InternalTimeQual)palloc(sizeof *qual);
+    
+    qual->start = startTime;
+    qual->end = endTime;
+    qual->mode = TimeQualEvery;
+    
+    if (AbsoluteTimeIsBackwardCompatiblyValid(startTime)) {
+	qual->mode |= TimeQualNewer;
+    }
+    if (AbsoluteTimeIsBackwardCompatiblyValid(endTime)) {
+	qual->mode |= TimeQualOlder;
+    }
+    
+    return ((TimeQual)qual);
+}
+
+/*
+ * HeapTupleSatisfiesTimeQual --
+ *	True iff heap tuple satsifies a time qual.
+ *
+ * Note:
+ *	Assumes heap tuple is valid.
+ *	Assumes time qual is valid.
+ *	XXX Many of the checks may be simplified and still remain correct.
+ *	XXX Partial answers to the checks may be cached in an ItemId.
+ */
+bool
+HeapTupleSatisfiesTimeQual(HeapTuple tuple, TimeQual qual)
+{
+/*    extern TransactionId AmiTransactionId; */
+    
+    Assert(HeapTupleIsValid(tuple));
+    Assert(TimeQualIsValid(qual));
+    
+    if (TransactionIdEquals(tuple->t_xmax, AmiTransactionId))
+	return(false);
+    
+    if (qual == SelfTimeQual || heapisoverride()) {
+	return (HeapTupleSatisfiesItself(tuple));
+    }
+    
+    if (qual == NowTimeQual) {
+	return (HeapTupleSatisfiesNow(tuple));
+    }
+    
+    if (!TimeQualIsLegal(qual)) {
+	elog(WARN, "HeapTupleSatisfiesTimeQual: illegal time qual");
+    }
+    
+    if (TimeQualIndicatesDisableValidityChecking(qual)) {
+	elog(WARN, "HeapTupleSatisfiesTimeQual: no disabled validity checking (yet)");
+    }
+    
+    if (TimeQualIsSnapshot(qual)) {
+	return (HeapTupleSatisfiesSnapshotInternalTimeQual(tuple,
+							   (InternalTimeQual)qual));
+    }
+    
+    if (TimeQualIncludesNow(qual)) {
+	return (HeapTupleSatisfiesUpperUnboundedInternalTimeQual(tuple,
+								 (InternalTimeQual)qual));
+    }
+    
+    return (HeapTupleSatisfiesUpperBoundedInternalTimeQual(tuple,
+							   (InternalTimeQual)qual));
+}
+
+/*
+ * HeapTupleSatisfiesItself --
+ *	True iff heap tuple is valid for "itself."
+ *
+ * Note:
+ *	Assumes heap tuple is valid.
+ */
+/*
+ * The satisfaction of "itself" requires the following:
+ *
+ * ((Xmin == my-transaction && (Xmax is null [|| Xmax != my-transaction)])
+ * ||
+ *
+ * (Xmin is committed &&
+ *	(Xmax is null || (Xmax != my-transaction && Xmax is not committed)))
+ */
+static bool
+HeapTupleSatisfiesItself(HeapTuple tuple)
+{
+    /*
+     * XXX Several evil casts are made in this routine.  Casting XID to be 
+     * TransactionId works only because TransactionId->data is the first
+     * (and only) field of the structure.
+     */
+    if (!AbsoluteTimeIsBackwardCompatiblyValid(tuple->t_tmin)) {
+	if (TransactionIdIsCurrentTransactionId((TransactionId)tuple->t_xmin) &&
+	    !TransactionIdIsValid((TransactionId)tuple->t_xmax)) {
+	    return (true);
+	}
+	
+	if (!TransactionIdDidCommit((TransactionId)tuple->t_xmin)) {
+	    return (false);
+	}
+    }
+    /* the tuple was inserted validly */
+    
+    if (AbsoluteTimeIsBackwardCompatiblyReal(tuple->t_tmax)) {
+	return (false);
+    }
+    
+    if (!TransactionIdIsValid((TransactionId)tuple->t_xmax)) {
+	return (true);
+    }
+    
+    if (TransactionIdIsCurrentTransactionId((TransactionId)tuple->t_xmax)) {
+	return (false);
+    }
+    
+    return ((bool)!TransactionIdDidCommit((TransactionId)tuple->t_xmax));
+}
+
+/*
+ * HeapTupleSatisfiesNow --
+ *	True iff heap tuple is valid "now."
+ *
+ * Note:
+ *	Assumes heap tuple is valid.
+ */
+/*
+ * The satisfaction of "now" requires the following:
+ *
+ * ((Xmin == my-transaction && Cmin != my-command &&
+ *	(Xmax is null || (Xmax == my-transaction && Cmax != my-command)))
+ * ||
+ *
+ * (Xmin is committed &&
+ *	(Xmax is null || (Xmax == my-transaction && Cmax == my-command) ||
+ *		(Xmax is not committed && Xmax != my-transaction))))
+ *
+ *	mao says 17 march 1993:  the tests in this routine are correct;
+ *	if you think they're not, you're wrong, and you should think
+ *	about it again.  i know, it happened to me.  we don't need to
+ *	check commit time against the start time of this transaction
+ *	because 2ph locking protects us from doing the wrong thing.
+ *	if you mess around here, you'll break serializability.  the only
+ *	problem with this code is that it does the wrong thing for system
+ *	catalog updates, because the catalogs aren't subject to 2ph, so
+ *	the serializability guarantees we provide don't extend to xacts
+ *	that do catalog accesses.  this is unfortunate, but not critical.
+ */
+static bool
+HeapTupleSatisfiesNow(HeapTuple tuple)
+{
+    if (AMI_OVERRIDE)
+	return true;
+    /*
+     *  If the transaction system isn't yet initialized, then we assume
+     *  that transactions committed.  We only look at system catalogs
+     *  during startup, so this is less awful than it seems, but it's
+     *  still pretty awful.
+     */
+    
+    if (!PostgresIsInitialized)
+	return ((bool)(TransactionIdIsValid((TransactionId)tuple->t_xmin) &&
+		       !TransactionIdIsValid((TransactionId)tuple->t_xmax)));
+    
+    /*
+     * XXX Several evil casts are made in this routine.  Casting XID to be 
+     * TransactionId works only because TransactionId->data is the first
+     * (and only) field of the structure.
+     */
+    if (!AbsoluteTimeIsBackwardCompatiblyValid(tuple->t_tmin)) {
+	
+	if (TransactionIdIsCurrentTransactionId((TransactionId)tuple->t_xmin)
+	    && CommandIdIsCurrentCommandId(tuple->t_cmin)) {
+	    
+	    return (false);
+	}
+	
+	if (TransactionIdIsCurrentTransactionId((TransactionId)tuple->t_xmin)
+	    && !CommandIdIsCurrentCommandId(tuple->t_cmin)) {
+	    
+	    if (!TransactionIdIsValid((TransactionId)tuple->t_xmax)) {
+		return (true);
+	    }
+	    
+	    Assert(TransactionIdIsCurrentTransactionId((TransactionId)tuple->t_xmax));
+	    
+	    if (CommandIdIsCurrentCommandId(tuple->t_cmax)) {
+		return (true);
+	    }
+	}
+	
+	/*
+	 * this call is VERY expensive - requires a log table lookup.
+	 */
+	
+	if (!TransactionIdDidCommit((TransactionId)tuple->t_xmin)) {
+	    return (false);
+	}
+    }
+    
+    /* by here, the inserting transaction has committed */
+    if (!TransactionIdIsValid((TransactionId)tuple->t_xmax)) {
+	return (true);
+    }
+    
+    if (TransactionIdIsCurrentTransactionId((TransactionId)tuple->t_xmax)) {
+	return (false);
+    }
+    
+    if (!TransactionIdDidCommit((TransactionId)tuple->t_xmax)) {
+	return (true);
+    }
+    
+    /* by here, deleting transaction has committed */
+    return (false);
+}
+
+/*
+ * HeapTupleSatisfiesSnapshotInternalTimeQual --
+ *	True iff heap tuple is valid at the snapshot time qualification.
+ *
+ * Note:
+ *	Assumes heap tuple is valid.
+ *	Assumes internal time qualification is valid snapshot qualification.
+ */
+/*
+ * The satisfaction of Rel[T] requires the following:
+ *
+ * (Xmin is committed && Tmin <= T &&
+ *	(Xmax is null || (Xmax is not committed && Xmax != my-transaction) ||
+ *		Tmax >= T))
+ */
+static bool
+HeapTupleSatisfiesSnapshotInternalTimeQual(HeapTuple tuple,
+					   InternalTimeQual qual)
+{
+    /*
+     * XXX Several evil casts are made in this routine.  Casting XID to be 
+     * TransactionId works only because TransactionId->data is the first
+     * (and only) field of the structure.
+     */
+    if (!AbsoluteTimeIsBackwardCompatiblyValid(tuple->t_tmin)) {
+	
+	if (!TransactionIdDidCommit((TransactionId)tuple->t_xmin)) {
+	    return (false);
+	}
+	
+	tuple->t_tmin = TransactionIdGetCommitTime(tuple->t_xmin);
+    }
+    
+    if (AbsoluteTimeIsBefore(TimeQualGetSnapshotTime((TimeQual)qual), tuple->t_tmin)) {
+	return (false);
+    }
+    /* the tuple was inserted validly before the snapshot time */
+    
+    if (!AbsoluteTimeIsBackwardCompatiblyReal(tuple->t_tmax)) {
+	
+	if (!TransactionIdIsValid((TransactionId)tuple->t_xmax) ||
+	    !TransactionIdDidCommit((TransactionId)tuple->t_xmax)) {
+	    
+	    return (true);
+	}
+	
+	tuple->t_tmax = TransactionIdGetCommitTime(tuple->t_xmax);
+    }
+    
+    return ((bool)
+	    AbsoluteTimeIsAfter(tuple->t_tmax,
+				TimeQualGetSnapshotTime((TimeQual)qual)));
+}
+
+/*
+ * HeapTupleSatisfiesUpperBoundedInternalTimeQual --
+ *	True iff heap tuple is valid within a upper bounded time qualification.
+ *
+ * Note:
+ *	Assumes heap tuple is valid.
+ *	Assumes time qualification is valid ranged qualification with fixed
+ *	upper bound.
+ */
+/*
+ * The satisfaction of [T1,T2] requires the following:
+ *
+ * (Xmin is committed && Tmin <= T2 &&
+ *	(Xmax is null || (Xmax is not committed && Xmax != my-transaction) ||
+ *		T1 is null || Tmax >= T1))
+ */
+static bool
+HeapTupleSatisfiesUpperBoundedInternalTimeQual(HeapTuple tuple,
+					       InternalTimeQual qual)
+{
+    /*
+     * XXX Several evil casts are made in this routine.  Casting XID to be 
+     * TransactionId works only because TransactionId->data is the first
+     * (and only) field of the structure.
+     */
+    if (!AbsoluteTimeIsBackwardCompatiblyValid(tuple->t_tmin)) {
+	
+	if (!TransactionIdDidCommit((TransactionId)tuple->t_xmin)) {
+	    return (false);
+	}
+	
+	tuple->t_tmin = TransactionIdGetCommitTime(tuple->t_xmin);
+    }
+    
+    if (AbsoluteTimeIsBefore(TimeQualGetEndTime((TimeQual)qual), tuple->t_tmin)) {
+	return (false);
+    }
+    /* the tuple was inserted validly before the range end */
+    
+    if (!AbsoluteTimeIsBackwardCompatiblyValid(TimeQualGetStartTime((TimeQual)qual))) {
+	return (true);
+    }
+    
+    if (!AbsoluteTimeIsBackwardCompatiblyReal(tuple->t_tmax)) {
+	
+	if (!TransactionIdIsValid((TransactionId)tuple->t_xmax) ||
+	    !TransactionIdDidCommit((TransactionId)tuple->t_xmax)) {
+	    
+	    return (true);
+	}
+	
+	tuple->t_tmax = TransactionIdGetCommitTime(tuple->t_xmax);
+    }
+    
+    return ((bool)AbsoluteTimeIsAfter(tuple->t_tmax,
+				      TimeQualGetStartTime((TimeQual)qual)));
+}
+
+/*
+ * HeapTupleSatisfiesUpperUnboundedInternalTimeQual --
+ *	True iff heap tuple is valid within a upper bounded time qualification.
+ *
+ * Note:
+ *	Assumes heap tuple is valid.
+ *	Assumes time qualification is valid ranged qualification with no
+ *	upper bound.
+ */
+/*
+ * The satisfaction of [T1,] requires the following:
+ *
+ * ((Xmin == my-transaction && Cmin != my-command &&
+ *	(Xmax is null || (Xmax == my-transaction && Cmax != my-command)))
+ * ||
+ *
+ * (Xmin is committed &&
+ *	(Xmax is null || (Xmax == my-transaction && Cmax == my-command) ||
+ *		(Xmax is not committed && Xmax != my-transaction) ||
+ *		T1 is null || Tmax >= T1)))
+ */
+static bool
+HeapTupleSatisfiesUpperUnboundedInternalTimeQual(HeapTuple tuple,
+						 InternalTimeQual qual)
+{
+    if (!AbsoluteTimeIsBackwardCompatiblyValid(tuple->t_tmin)) {
+	
+	if (TransactionIdIsCurrentTransactionId((TransactionId)tuple->t_xmin) &&
+	    CommandIdIsCurrentCommandId(tuple->t_cmin)) {
+	    
+	    return (false);
+	}
+	
+	if (TransactionIdIsCurrentTransactionId((TransactionId)tuple->t_xmin) &&
+	    !CommandIdIsCurrentCommandId(tuple->t_cmin)) {
+	    
+	    if (!TransactionIdIsValid((TransactionId)tuple->t_xmax)) {
+		return (true);
+	    }
+	    
+	    Assert(TransactionIdIsCurrentTransactionId((TransactionId)tuple->t_xmax));
+	    
+	    return ((bool) !CommandIdIsCurrentCommandId(tuple->t_cmax));
+	}
+	
+	if (!TransactionIdDidCommit((TransactionId)tuple->t_xmin)) {
+	    return (false);
+	}
+	
+	tuple->t_tmin = TransactionIdGetCommitTime(tuple->t_xmin);
+    }
+    /* the tuple was inserted validly */
+    
+    if (!AbsoluteTimeIsBackwardCompatiblyValid(TimeQualGetStartTime((TimeQual)qual))) {
+	return (true);
+    }
+    
+    if (!AbsoluteTimeIsBackwardCompatiblyReal(tuple->t_tmax)) {
+	
+	if (!TransactionIdIsValid((TransactionId)tuple->t_xmax)) {
+	    return (true);
+	}
+	
+	if (TransactionIdIsCurrentTransactionId((TransactionId)tuple->t_xmax)) {
+	    return (CommandIdIsCurrentCommandId(tuple->t_cmin));
+	}
+	
+	if (!TransactionIdDidCommit((TransactionId)tuple->t_xmax)) {
+	    return (true);
+	}
+	
+	tuple->t_tmax = TransactionIdGetCommitTime(tuple->t_xmax);
+    }
+    
+    return ((bool)AbsoluteTimeIsAfter(tuple->t_tmax,
+				      TimeQualGetStartTime((TimeQual)qual)));
+}