Cosmetic cleanup of ginInsertValue().

Make it clearer that the passed stack mustn't be empty, and that we
are not supposed to fall off the end of the stack in the main loop.
Tighten the loop that extracts the root block number, too.

Markus Wanner and Tom Lane

diff --git a/src/backend/access/gin/ginbtree.c b/src/backend/access/gin/ginbtree.c
index b160551b5ed6ed16693904488b9c3bda7e0146d3..82ac53e148724502e5bd51a33df37a040274c53d 100644 (file)
--- a/src/backend/access/gin/ginbtree.c
+++ b/src/backend/access/gin/ginbtree.c
@@ -275,20 +275,22 @@ ginFindParents(GinBtree btree, GinBtreeStack *stack,
 void
 ginInsertValue(GinBtree btree, GinBtreeStack *stack, GinStatsData *buildStats)
 {
-       GinBtreeStack *parent = stack;
-       BlockNumber rootBlkno = InvalidBuffer;
+       GinBtreeStack *parent;
+       BlockNumber rootBlkno;
        Page            page,
                                rpage,
                                lpage;
 
-       /* remember root BlockNumber */
-       while (parent)
-       {
-               rootBlkno = parent->blkno;
+       /* extract root BlockNumber from stack */
+       Assert(stack != NULL);
+       parent = stack;
+       while (parent->parent)
                parent = parent->parent;
-       }
+       rootBlkno = parent->blkno;
+       Assert(BlockNumberIsValid(rootBlkno));
 
-       while (stack)
+       /* this loop crawls up the stack until the insertion is complete */
+       for (;;)
        {
                XLogRecData *rdata;
                BlockNumber savedRightLink;
@@ -457,7 +459,7 @@ ginInsertValue(GinBtree btree, GinBtreeStack *stack, GinStatsData *buildStats)
                                 */
                                ginFindParents(btree, stack, rootBlkno);
                                parent = stack->parent;
-                               page = BufferGetPage(parent->buffer);
+                               Assert(parent != NULL);
                                break;
                        }