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Renumber SnapshotNow and the other special snapshot codes so that

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((Snapshot) NULL) can no longer be confused with a valid snapshot,
as per my recent suggestion.  Define a macro InvalidSnapshot for 0.
Use InvalidSnapshot instead of SnapshotAny as the do-nothing special
case for heap_update and heap_delete crosschecks; this seems a little
cleaner even though the behavior is really the same.
This commit is contained in:
Tom Lane
2004-09-11 18:28:34 +00:00
parent 9835944e54
commit 493f72606b
5 changed files with 38 additions and 20 deletions
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20
src/backend/access/heap/heapam.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.173 2004/08/29 05:06:40 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.174 2004/09/11 18:28:32 tgl Exp $
*
*
* INTERFACE ROUTINES
@ -1262,7 +1262,7 @@ simple_heap_insert(Relation relation, HeapTuple tup)
* tid - TID of tuple to be deleted
* ctid - output parameter, used only for failure case (see below)
* cid - delete command ID to use in verifying tuple visibility
* crosscheck - if not SnapshotAny, also check tuple against this
* crosscheck - if not InvalidSnapshot, also check tuple against this
* wait - true if should wait for any conflicting update to commit/abort
*
* Normal, successful return value is HeapTupleMayBeUpdated, which
@ -1274,7 +1274,8 @@ simple_heap_insert(Relation relation, HeapTuple tup)
*/
int
heap_delete(Relation relation, ItemPointer tid,
ItemPointer ctid, CommandId cid, Snapshot crosscheck, bool wait)
ItemPointer ctid, CommandId cid,
Snapshot crosscheck, bool wait)
{
ItemId lp;
HeapTupleData tp;
@ -1339,7 +1340,7 @@ l1:
result = HeapTupleUpdated;
}
if (crosscheck != SnapshotAny && result == HeapTupleMayBeUpdated)
if (crosscheck != InvalidSnapshot && result == HeapTupleMayBeUpdated)
{
/* Perform additional check for serializable RI updates */
if (!HeapTupleSatisfiesSnapshot(tp.t_data, crosscheck))
@ -1443,7 +1444,7 @@ simple_heap_delete(Relation relation, ItemPointer tid)
result = heap_delete(relation, tid,
&ctid,
GetCurrentCommandId(), SnapshotAny,
GetCurrentCommandId(), InvalidSnapshot,
true /* wait for commit */ );
switch (result)
{
@ -1477,7 +1478,7 @@ simple_heap_delete(Relation relation, ItemPointer tid)
* newtup - newly constructed tuple data to store
* ctid - output parameter, used only for failure case (see below)
* cid - update command ID to use in verifying old tuple visibility
* crosscheck - if not SnapshotAny, also check old tuple against this
* crosscheck - if not InvalidSnapshot, also check old tuple against this
* wait - true if should wait for any conflicting update to commit/abort
*
* Normal, successful return value is HeapTupleMayBeUpdated, which
@ -1491,7 +1492,8 @@ simple_heap_delete(Relation relation, ItemPointer tid)
*/
int
heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
ItemPointer ctid, CommandId cid, Snapshot crosscheck, bool wait)
ItemPointer ctid, CommandId cid,
Snapshot crosscheck, bool wait)
{
ItemId lp;
HeapTupleData oldtup;
@ -1566,7 +1568,7 @@ l2:
result = HeapTupleUpdated;
}
if (crosscheck != SnapshotAny && result == HeapTupleMayBeUpdated)
if (crosscheck != InvalidSnapshot && result == HeapTupleMayBeUpdated)
{
/* Perform additional check for serializable RI updates */
if (!HeapTupleSatisfiesSnapshot(oldtup.t_data, crosscheck))
@ -1804,7 +1806,7 @@ simple_heap_update(Relation relation, ItemPointer otid, HeapTuple tup)
result = heap_update(relation, otid, tup,
&ctid,
GetCurrentCommandId(), SnapshotAny,
GetCurrentCommandId(), InvalidSnapshot,
true /* wait for commit */ );
switch (result)
{