If we have to split leaf page in the chain of duplicates

then we try to look at our right sibling first, but not farther,
as it was in yesterday fix.

diff --git a/src/backend/access/nbtree/nbtinsert.c b/src/backend/access/nbtree/nbtinsert.c
index 5349277..c4f0fc0 100644 (file)
--- a/src/backend/access/nbtree/nbtinsert.c
+++ b/src/backend/access/nbtree/nbtinsert.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *    $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.13 1997/05/30 18:35:31 vadim Exp $
+ *    $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.14 1997/05/31 06:35:56 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -287,31 +287,22 @@ _bt_insertonpg(Relation rel,
        
        /* 
         * If we have to split leaf page in the chain of duplicates
-        * then we try to move righter to avoid splitting.
+        * then we try to look at our right sibling first.
         */
        if ( ( lpageop->btpo_flags & BTP_CHAIN ) &&
                        ( lpageop->btpo_flags & BTP_LEAF ) )
        {
            bool use_left = true;
+           bool keys_equal = false;
                
-           for ( ; ; )
-           {
-               bool keys_equal = false;
-                   
-               rbuf = _bt_getbuf(rel, lpageop->btpo_next, BT_WRITE);
-               rpage = BufferGetPage(rbuf);
-               rpageop = (BTPageOpaque) PageGetSpecialPointer(rpage);
-               if ( P_RIGHTMOST (rpageop) )
-               {
-                   Assert ( !( rpageop->btpo_flags & BTP_CHAIN ) );
-                   use_left = false;
-                   break;
-               }
-               /*
+           rbuf = _bt_getbuf(rel, lpageop->btpo_next, BT_WRITE);
+           rpage = BufferGetPage(rbuf);
+           rpageop = (BTPageOpaque) PageGetSpecialPointer(rpage);
+           if ( !P_RIGHTMOST (rpageop) )       /* non-rightmost page */
+           {   /*
                 * If we have the same hikey here then it's
-                * yet another page in chain and we may move
-                * even righter.
-                */
+                * yet another page in chain.
+                */
                if ( _bt_skeycmp (rel, keysz, scankey, rpage, 
                                        PageGetItemId(rpage, P_HIKEY), 
                                        BTEqualStrategyNumber) )
@@ -321,12 +312,12 @@ _bt_insertonpg(Relation rel,
                    keys_equal = true;
                }
                else if ( _bt_skeycmp (rel, keysz, scankey, rpage, 
-                                       PageGetItemId(rpage, P_HIKEY), 
-                                       BTGreaterStrategyNumber) )
-                   elog (FATAL, "btree: hikey is out of order");
+                               PageGetItemId(rpage, P_HIKEY), 
+                               BTGreaterStrategyNumber) )
+                   elog (FATAL, "btree: hikey is out of order");
                /*
                 * If hikey > scankey and BTP_CHAIN is ON 
-                * then it's first page of the chain of higher keys:
+                * then it's first page of the chain of higher keys:
                 * our left sibling hikey was lying! We can't add new 
                 * item here, but we can turn BTP_CHAIN off on our
                 * left page and overwrite its hikey.
@@ -336,26 +327,19 @@ _bt_insertonpg(Relation rel,
                    BTItem tmp;
                    
                    lpageop->btpo_flags &= ~BTP_CHAIN;
-                   tmp = (BTItem) PageGetItem(rpage, 
-                                       PageGetItemId(rpage, P_HIKEY));
+                   tmp = (BTItem) PageGetItem(rpage, PageGetItemId(rpage, P_HIKEY));
                    hiRightItem = _bt_formitem(&(tmp->bti_itup));
-                   break;
                }
-               /* 
-                * if there is room here or hikey > scankey (so it's our
-                * last page in the chain and we can't move righter) 
-                * we have to use this page .
-                */
-               if ( PageGetFreeSpace (rpage) > itemsz || !keys_equal )
-               {
+               /* if there is room here then we use this page. */
+               else if ( PageGetFreeSpace (rpage) > itemsz )
+                   use_left = false;
+           }
+           else        /* rightmost page */
+           {
+               Assert ( !( rpageop->btpo_flags & BTP_CHAIN ) );
+               /* if there is room here then we use this page. */
+               if ( PageGetFreeSpace (rpage) > itemsz )
                    use_left = false;
-                   break;
-               }
-               /* try to move righter */
-               _bt_relbuf(rel, buf, BT_WRITE);
-               buf = rbuf;
-               page = rpage;
-               lpageop = rpageop;
            }
            if ( !use_left )    /* insert on the right page */
            {
@@ -364,7 +348,6 @@ _bt_insertonpg(Relation rel,
                                        scankey, btitem, afteritem) );
            }
            _bt_relbuf(rel, rbuf, BT_WRITE);
-           bknum = BufferGetBlockNumber(buf);
        }
        
        /* split the buffer into left and right halves */