Remove PageSetTLI and rename pd_tli to pd_checksum

Remove use of PageSetTLI() from all page manipulation functions
and adjust README to indicate change in the way we make changes
to pages. Repurpose those bytes into the pd_checksum field and
explain how that works in comments about page header.

Refactoring ahead of actual feature patch which would make use
of the checksum field, arriving later.

Jeff Davis, with comments and doc changes by Simon Riggs
Direction suggested by Robert Haas; many others providing
review comments.

1 files changed, 2 insertions, 23 deletions

diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 5250ec7f419..151422a1b06 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -2129,7 +2129,6 @@ heap_insert(Relation relation, HeapTuple tup, CommandId cid,
 		recptr = XLogInsert(RM_HEAP_ID, info, rdata);
 
 		PageSetLSN(page, recptr);
-		PageSetTLI(page, ThisTimeLineID);
 	}
 
 	END_CRIT_SECTION();
@@ -2426,7 +2425,6 @@ heap_multi_insert(Relation relation, HeapTuple *tuples, int ntuples,
 			recptr = XLogInsert(RM_HEAP2_ID, info, rdata);
 
 			PageSetLSN(page, recptr);
-			PageSetTLI(page, ThisTimeLineID);
 		}
 
 		END_CRIT_SECTION();
@@ -2787,7 +2785,6 @@ l1:
 		recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_DELETE, rdata);
 
 		PageSetLSN(page, recptr);
-		PageSetTLI(page, ThisTimeLineID);
 	}
 
 	END_CRIT_SECTION();
@@ -3570,10 +3567,8 @@ l2:
 		if (newbuf != buffer)
 		{
 			PageSetLSN(BufferGetPage(newbuf), recptr);
-			PageSetTLI(BufferGetPage(newbuf), ThisTimeLineID);
 		}
 		PageSetLSN(BufferGetPage(buffer), recptr);
-		PageSetTLI(BufferGetPage(buffer), ThisTimeLineID);
 	}
 
 	END_CRIT_SECTION();
@@ -4472,7 +4467,6 @@ failed:
 		recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_LOCK, rdata);
 
 		PageSetLSN(page, recptr);
-		PageSetTLI(page, ThisTimeLineID);
 	}
 
 	END_CRIT_SECTION();
@@ -4889,7 +4883,6 @@ l4:
 			recptr = XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_LOCK_UPDATED, rdata);
 
 			PageSetLSN(page, recptr);
-			PageSetTLI(page, ThisTimeLineID);
 		}
 
 		END_CRIT_SECTION();
@@ -5033,7 +5026,6 @@ heap_inplace_update(Relation relation, HeapTuple tuple)
 		recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_INPLACE, rdata);
 
 		PageSetLSN(page, recptr);
-		PageSetTLI(page, ThisTimeLineID);
 	}
 
 	END_CRIT_SECTION();
@@ -5915,7 +5907,6 @@ log_newpage(RelFileNode *rnode, ForkNumber forkNum, BlockNumber blkno,
 	if (!PageIsNew(page))
 	{
 		PageSetLSN(page, recptr);
-		PageSetTLI(page, ThisTimeLineID);
 	}
 
 	END_CRIT_SECTION();
@@ -5964,7 +5955,6 @@ log_newpage_buffer(Buffer buffer)
 	if (!PageIsNew(page))
 	{
 		PageSetLSN(page, recptr);
-		PageSetTLI(page, ThisTimeLineID);
 	}
 
 	return recptr;
@@ -6066,7 +6056,6 @@ heap_xlog_clean(XLogRecPtr lsn, XLogRecord *record)
 	 */
 
 	PageSetLSN(page, lsn);
-	PageSetTLI(page, ThisTimeLineID);
 	MarkBufferDirty(buffer);
 	UnlockReleaseBuffer(buffer);
 
@@ -6134,7 +6123,6 @@ heap_xlog_freeze(XLogRecPtr lsn, XLogRecord *record)
 	}
 
 	PageSetLSN(page, lsn);
-	PageSetTLI(page, ThisTimeLineID);
 	MarkBufferDirty(buffer);
 	UnlockReleaseBuffer(buffer);
 }
@@ -6262,13 +6250,12 @@ heap_xlog_newpage(XLogRecPtr lsn, XLogRecord *record)
 	memcpy(page, (char *) xlrec + SizeOfHeapNewpage, BLCKSZ);
 
 	/*
-	 * The page may be uninitialized. If so, we can't set the LSN and TLI
-	 * because that would corrupt the page.
+	 * The page may be uninitialized. If so, we can't set the LSN because that
+	 * would corrupt the page.
 	 */
 	if (!PageIsNew(page))
 	{
 		PageSetLSN(page, lsn);
-		PageSetTLI(page, ThisTimeLineID);
 	}
 
 	MarkBufferDirty(buffer);
@@ -6374,7 +6361,6 @@ heap_xlog_delete(XLogRecPtr lsn, XLogRecord *record)
 	/* Make sure there is no forward chain link in t_ctid */
 	htup->t_ctid = xlrec->target.tid;
 	PageSetLSN(page, lsn);
-	PageSetTLI(page, ThisTimeLineID);
 	MarkBufferDirty(buffer);
 	UnlockReleaseBuffer(buffer);
 }
@@ -6473,7 +6459,6 @@ heap_xlog_insert(XLogRecPtr lsn, XLogRecord *record)
 	freespace = PageGetHeapFreeSpace(page);		/* needed to update FSM below */
 
 	PageSetLSN(page, lsn);
-	PageSetTLI(page, ThisTimeLineID);
 
 	if (xlrec->all_visible_cleared)
 		PageClearAllVisible(page);
@@ -6620,7 +6605,6 @@ heap_xlog_multi_insert(XLogRecPtr lsn, XLogRecord *record)
 	freespace = PageGetHeapFreeSpace(page);		/* needed to update FSM below */
 
 	PageSetLSN(page, lsn);
-	PageSetTLI(page, ThisTimeLineID);
 
 	if (xlrec->all_visible_cleared)
 		PageClearAllVisible(page);
@@ -6762,7 +6746,6 @@ heap_xlog_update(XLogRecPtr lsn, XLogRecord *record, bool hot_update)
 	}
 
 	PageSetLSN(page, lsn);
-	PageSetTLI(page, ThisTimeLineID);
 	MarkBufferDirty(obuffer);
 
 	/* Deal with new tuple */
@@ -6861,7 +6844,6 @@ newsame:;
 	freespace = PageGetHeapFreeSpace(page);		/* needed to update FSM below */
 
 	PageSetLSN(page, lsn);
-	PageSetTLI(page, ThisTimeLineID);
 	MarkBufferDirty(nbuffer);
 	UnlockReleaseBuffer(nbuffer);
 
@@ -6936,7 +6918,6 @@ heap_xlog_lock(XLogRecPtr lsn, XLogRecord *record)
 	/* Make sure there is no forward chain link in t_ctid */
 	htup->t_ctid = xlrec->target.tid;
 	PageSetLSN(page, lsn);
-	PageSetTLI(page, ThisTimeLineID);
 	MarkBufferDirty(buffer);
 	UnlockReleaseBuffer(buffer);
 }
@@ -6986,7 +6967,6 @@ heap_xlog_lock_updated(XLogRecPtr lsn, XLogRecord *record)
 	HeapTupleHeaderSetXmax(htup, xlrec->xmax);
 
 	PageSetLSN(page, lsn);
-	PageSetTLI(page, ThisTimeLineID);
 	MarkBufferDirty(buffer);
 	UnlockReleaseBuffer(buffer);
 }
@@ -7042,7 +7022,6 @@ heap_xlog_inplace(XLogRecPtr lsn, XLogRecord *record)
 		   newlen);
 
 	PageSetLSN(page, lsn);
-	PageSetTLI(page, ThisTimeLineID);
 	MarkBufferDirty(buffer);
 	UnlockReleaseBuffer(buffer);
 }