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 534927717fc106df282b130f8643d3f94f8987e6..c4f0fc0d04fe597d43a9f4bc4395e7c1961a5aea 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 */