Modify BufferGetPage() to prepare for "snapshot too old" feature

This patch is a no-op patch which is intended to reduce the chances
of failures of omission once the functional part of the "snapshot
too old" patch goes in.  It adds parameters for snapshot, relation,
and an enum to specify whether the snapshot age check needs to be
done for the page at this point.  This initial patch passes NULL
for the first two new parameters and BGP_NO_SNAPSHOT_TEST for the
third.  The follow-on patch will change the places where the test
needs to be made.

1 files changed, 7 insertions, 5 deletions

diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 59beadda9d1..19201b0bca5 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -74,7 +74,7 @@ static void heap_prune_record_unused(PruneState *prstate, OffsetNumber offnum);
 void
 heap_page_prune_opt(Relation relation, Buffer buffer)
 {
-	Page		page = BufferGetPage(buffer);
+	Page		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 	Size		minfree;
 	TransactionId OldestXmin;
 
@@ -174,7 +174,7 @@ heap_page_prune(Relation relation, Buffer buffer, TransactionId OldestXmin,
 				bool report_stats, TransactionId *latestRemovedXid)
 {
 	int			ndeleted = 0;
-	Page		page = BufferGetPage(buffer);
+	Page		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 	OffsetNumber offnum,
 				maxoff;
 	PruneState	prstate;
@@ -261,7 +261,8 @@ heap_page_prune(Relation relation, Buffer buffer, TransactionId OldestXmin,
 									prstate.nowunused, prstate.nunused,
 									prstate.latestRemovedXid);
 
-			PageSetLSN(BufferGetPage(buffer), recptr);
+			PageSetLSN(BufferGetPage(buffer, NULL, NULL,
+									 BGP_NO_SNAPSHOT_TEST), recptr);
 		}
 	}
 	else
@@ -347,7 +348,7 @@ heap_prune_chain(Relation relation, Buffer buffer, OffsetNumber rootoffnum,
 				 PruneState *prstate)
 {
 	int			ndeleted = 0;
-	Page		dp = (Page) BufferGetPage(buffer);
+	Page		dp = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 	TransactionId priorXmax = InvalidTransactionId;
 	ItemId		rootlp;
 	HeapTupleHeader htup;
@@ -673,7 +674,8 @@ heap_page_prune_execute(Buffer buffer,
 						OffsetNumber *nowdead, int ndead,
 						OffsetNumber *nowunused, int nunused)
 {
-	Page		page = (Page) BufferGetPage(buffer);
+	Page		page = BufferGetPage(buffer, NULL, NULL,
+									 BGP_NO_SNAPSHOT_TEST);
 	OffsetNumber *offnum;
 	int			i;