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, 0 insertions, 8 deletions

diff --git a/src/backend/access/nbtree/nbtinsert.c b/src/backend/access/nbtree/nbtinsert.c
index 6ed51fea156..63e099b0fd9 100644
--- a/src/backend/access/nbtree/nbtinsert.c
+++ b/src/backend/access/nbtree/nbtinsert.c
@@ -858,11 +858,9 @@ _bt_insertonpg(Relation rel,
 			if (BufferIsValid(metabuf))
 			{
 				PageSetLSN(metapg, recptr);
-				PageSetTLI(metapg, ThisTimeLineID);
 			}
 
 			PageSetLSN(page, recptr);
-			PageSetTLI(page, ThisTimeLineID);
 		}
 
 		END_CRIT_SECTION();
@@ -946,7 +944,6 @@ _bt_split(Relation rel, Buffer buf, OffsetNumber firstright,
 	 * examine these fields and possibly dump them in a page image.
 	 */
 	PageSetLSN(leftpage, PageGetLSN(origpage));
-	PageSetTLI(leftpage, PageGetTLI(origpage));
 
 	/* init btree private data */
 	oopaque = (BTPageOpaque) PageGetSpecialPointer(origpage);
@@ -1319,13 +1316,10 @@ _bt_split(Relation rel, Buffer buf, OffsetNumber firstright,
 		recptr = XLogInsert(RM_BTREE_ID, xlinfo, rdata);
 
 		PageSetLSN(origpage, recptr);
-		PageSetTLI(origpage, ThisTimeLineID);
 		PageSetLSN(rightpage, recptr);
-		PageSetTLI(rightpage, ThisTimeLineID);
 		if (!P_RIGHTMOST(ropaque))
 		{
 			PageSetLSN(spage, recptr);
-			PageSetTLI(spage, ThisTimeLineID);
 		}
 	}
 
@@ -1961,9 +1955,7 @@ _bt_newroot(Relation rel, Buffer lbuf, Buffer rbuf)
 		recptr = XLogInsert(RM_BTREE_ID, XLOG_BTREE_NEWROOT, rdata);
 
 		PageSetLSN(rootpage, recptr);
-		PageSetTLI(rootpage, ThisTimeLineID);
 		PageSetLSN(metapg, recptr);
-		PageSetTLI(metapg, ThisTimeLineID);
 	}
 
 	END_CRIT_SECTION();