Changeset 45 for hw

Timestamp:

09/25/07 19:23:59 (5 years ago)

Author:

cs186

Message:

Better comments in gistnext_checksplit

Files:

• hw/hw2/postgresql-8.2.4/src/backend/access/gist/gistget.c (modified) (2 diffs)

hw/hw2/postgresql-8.2.4/src/backend/access/gist/gistget.c

@@ -209 +209 @@
 }
 
-/* 
- * Support routine for gistnext.  Deals with concurrency control issues to 
- * check if a node on the (cached) search stack was split by a concurrent
- * inserter.  If so, the result of the split can be found by adding right-hand 
- * neighbors of the split node to the search stack.  See 
- * Kornacker/Mohan/Hellerstein, SIGMOD 1997, for the protocol description.
+/*
+ * Support routine for gistnext.  Deals with concurrency control issues to
+ * check if the top node on the search stack was split by a concurrent
+ * inserter since the time it was put on the stack.  If so, the "rest"
+ * of the split can be found by adding the right-hand
+ * neighbor of the split node to the search stack.  See
+ * Kornacker/Mohan/Hellerstein, SIGMOD 1997, for details.
  */
 static void
@@ -238 +239 @@
       /* detect page split, follow right link to add pages */
 
+      /* 
+       * CS186 HW2: Fix me!
+       * Modify this next code to put the rightlinked block on
+       * the priority queue.
+       * Note: since this page was split since it was inserted into
+       * the priority queue, it has fewer items on it, and a different
+       * bounding box, so its priority may have changed.
+       */
       stk = (GISTSearchStack *) palloc0(sizeof(GISTSearchStack));
       stk->next = so->stack->next;