From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 26 Feb 2014 13:18:17 +0000 (-0500)
Subject: More hacking.
X-Git-Url: http://git.postgresql.org/gitweb/static/developers.postgresql.org?a=commitdiff_plain;h=997a74483b8ed5ddee68822cd24ba3a5c4a87f79;p=users%2Frhaas%2Fpostgres.git

More hacking.
---

diff --git a/src/backend/utils/mmgr/freepage.c b/src/backend/utils/mmgr/freepage.c
index 45bfc4a80f..a891a039da 100644
--- a/src/backend/utils/mmgr/freepage.c
+++ b/src/backend/utils/mmgr/freepage.c
@@ -84,6 +84,8 @@ typedef struct FreePageBtreeSearchResult
 /* Helper functions */
 static void FreePageBtreeAdjustAncestorKeys(FreePageManager *fpm,
 					FreePageBtree *btp);
+static FreePageBtree *FreePageBtreeFindRightSibling(char *base,
+							  FreePageBtree *btp);
 static Size FreePageBtreeFirstKey(FreePageBtree *btp);
 static FreePageBtree *FreePageBtreeGetRecycled(FreePageManager *fpm);
 static void FreePageBtreeInsertInternal(char *base, FreePageBtree *btp,
@@ -364,6 +366,45 @@ FreePageBtreeAdjustAncestorKeys(FreePageManager *fpm, FreePageBtree *btp)
 	}
 }
 
+/*
+ * Find the leaf page which follows the passed page in key order.
+ */
+static FreePageBtree *
+FreePageBtreeFindRightSibling(char *base, FreePageBtree *btp)
+{
+	Assert(btp->hdr.magic == FREE_PAGE_LEAF_MAGIC);
+
+	/* Move up until we can move right. */
+	for (;;)
+	{
+		Size	first_page;
+		Size	index;
+
+		if (btp->hdr.magic == FREE_PAGE_LEAF_MAGIC)
+			first_page = btp->u.leaf_key[0].first_page;
+		else
+			first_page = btp->u.internal_key[0].first_page;
+		btp = relptr_access(base, btp->hdr.parent);
+
+		if (btp == NULL)
+			return NULL;		/* we were passed the rightmost page */
+
+		index = FreePageBtreeSearchInternal(btp, first_page);
+		if (index < btp->hdr.nused - 1)
+		{
+			btp = relptr_access(base, btp->u.internal_key[index + 1].child);
+			break;
+		}
+		Assert(index == btp->hdr.nused - 1);
+	}
+
+	/* Descend left. */
+	while (btp->hdr.magic == FREE_PAGE_INTERNAL_MAGIC)
+		btp = relptr_access(base, btp->u.internal_key[0].child);
+
+	return btp;
+}
+
 /*
  * Get the first key on a btree page.
  */
@@ -1044,31 +1085,10 @@ FreePageManagerPutInternal(FreePageManager *fpm, Size first_page, Size npages,
 	}
 	else
 	{
-		/*
-		 * We need to find the right sibling of the insertion point to
-		 * determine whether we can consolidate with the following key.
-		 * Move up until we can move right; then descend left.
-		 */
-		np = result.page;
-		for (;;)
-		{
-			np = relptr_access(base, np->hdr.parent);
-			if (np == NULL)
-				break;			/* no next key exists */
-			nindex = FreePageBtreeSearchInternal(np, first_page);
-			if (nindex < np->hdr.nused)
-			{
-				np = relptr_access(base, np->u.internal_key[nindex].child);
-				break;
-			}
-		}
+		np = FreePageBtreeFindRightSibling(base, result.page);
+		nindex = 0;
 		if (np != NULL)
-		{
-			while (np->hdr.magic == FREE_PAGE_INTERNAL_MAGIC)
-				np = relptr_access(base, np->u.internal_key[0].child);
 			nextkey = &np->u.leaf_key[0];
-			nindex = 0;
-		}
 	}
 
 	/* Consolidate with the previous entry if possible. */