1. Vacuum is updated for MVCC.

2. Much faster btree tuples deletion in the case when first on page
   index tuple is deleted (no movement to the left page(s)).
3. Remember blkno of new root page in BTPageOpaque of
   left/right siblings when root page is splitted.

1 files changed, 18 insertions, 19 deletions

diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c
index 5ae59ccf12..2ded78b1a6 100644
--- a/src/backend/access/nbtree/nbtree.c
+++ b/src/backend/access/nbtree/nbtree.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtree.c,v 1.36 1999/02/21 03:48:27 scrappy Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtree.c,v 1.37 1999/03/28 20:31:58 vadim Exp $
  *
  * NOTES
  *	  This file contains only the public interface routines.
@@ -372,11 +372,6 @@ btinsert(Relation rel, Datum *datum, char *nulls, ItemPointer ht_ctid, Relation
 	pfree(btitem);
 	pfree(itup);
 
-#ifdef NOT_USED
-	/* adjust any active scans that will be affected by this insertion */
-	_bt_adjscans(rel, &(res->pointerData), BT_INSERT);
-#endif
-
 	return res;
 }
 
@@ -396,15 +391,9 @@ btgettuple(IndexScanDesc scan, ScanDirection dir)
 
 	if (ItemPointerIsValid(&(scan->currentItemData)))
 	{
-
 		/*
-		 * Now we don't adjust scans on insertion (comments in
-		 * nbtscan.c:_bt_scandel()) and I hope that we will unlock current
-		 * index page before leaving index in LLL: this means that current
-		 * index tuple could be moved right before we get here and we have
-		 * to restore our scan position. We save heap TID pointed by
-		 * current index tuple and use it. This will work untill we start
-		 * to re-use (move heap tuples) without vacuum... - vadim 07/29/98
+		 * Restore scan position using heap TID returned 
+		 * by previous call to btgettuple().
 		 */
 		_bt_restscan(scan);
 		res = _bt_next(scan, dir);
@@ -612,16 +601,12 @@ void
 btdelete(Relation rel, ItemPointer tid)
 {
 	/* adjust any active scans that will be affected by this deletion */
-	_bt_adjscans(rel, tid, BT_DELETE);
+	_bt_adjscans(rel, tid);
 
 	/* delete the data from the page */
 	_bt_pagedel(rel, tid);
 }
 
-/*
- * Reasons are in btgettuple... We have to find index item that
- * points to heap tuple returned by previous call to btgettuple().
- */
 static void
 _bt_restscan(IndexScanDesc scan)
 {
@@ -637,6 +622,20 @@ _bt_restscan(IndexScanDesc scan)
 	BTItem		item;
 	BlockNumber blkno;
 
+	/*
+	 * We use this as flag when first index tuple on page
+	 * is deleted but we do not move left (this would
+	 * slowdown vacuum) - so we set current->ip_posid
+	 * before first index tuple on the current page
+	 * (_bt_step will move it right)...
+	 */
+	if (!ItemPointerIsValid(&target))
+	{
+		ItemPointerSetOffsetNumber(&(scan->currentItemData), 
+			OffsetNumberPrev(P_RIGHTMOST(opaque) ? P_HIKEY : P_FIRSTKEY));
+		return;
+	}
+
 	if (maxoff >= offnum)
 	{