From: Robert Haas <rhaas@postgresql.org>
Date: Sun, 10 Jun 2012 12:47:32 +0000 (-0400)
Subject: Add GiST metabuffer.
X-Git-Url: http://git.postgresql.org/gitweb/static/developers.postgresql.org?a=commitdiff_plain;h=832781f752fde3507bc0ee6fd01ebecdac0966b3;p=users%2Frhaas%2Fpostgres.git

Add GiST metabuffer.
---

diff --git a/src/backend/access/gist/gistbuild.c b/src/backend/access/gist/gistbuild.c
index 9d68afb64f..5006577efc 100644
--- a/src/backend/access/gist/gistbuild.c
+++ b/src/backend/access/gist/gistbuild.c
@@ -73,6 +73,7 @@ typedef struct
 } GISTBuildState;
 
 /* prototypes for private functions */
+static void GistInitMetabuffer(Relation index, Buffer buffer, BlockNumber root);
 static void gistInitBuffering(GISTBuildState *buildstate);
 static int	calculatePagesPerBuffer(GISTBuildState *buildstate, int levelStep);
 static void gistBuildCallback(Relation index,
@@ -117,8 +118,11 @@ gistbuild(PG_FUNCTION_ARGS)
 	IndexBuildResult *result;
 	double		reltuples;
 	GISTBuildState buildstate;
-	Buffer		rootbuffer;
-	Page		rootpage;
+	Buffer		metabuffer,
+				rootbuffer;
+	Page		metapage,
+				rootpage;
+	BlockNumber	rootblock;
 	MemoryContext oldcxt = CurrentMemoryContext;
 	int			fillfactor;
 
@@ -178,12 +182,17 @@ gistbuild(PG_FUNCTION_ARGS)
 	 */
 	buildstate.giststate->tempCxt = createTempGistContext();
 
-	/* initialize the root page */
+	/* initialize the metabuffer and root buffer */
+	metabuffer = gistNewBuffer(index);
+	metapage = BufferGetPage(metabuffer);
+	Assert(BufferGetBlockNumber(metabuffer) == GIST_METAPAGE_BLKNO);
 	rootbuffer = gistNewBuffer(index);
 	rootpage = BufferGetPage(rootbuffer);
+	rootblock = BufferGetBlockNumber(rootbuffer);
 
 	START_CRIT_SECTION();
 
+	GistInitMetabuffer(index, metabuffer, rootblock);
 	GISTInitBuffer(rootbuffer, F_LEAF | F_ROOT);
 
 	MarkBufferDirty(rootbuffer);
@@ -195,7 +204,7 @@ gistbuild(PG_FUNCTION_ARGS)
 		gistxlogCreateIndex	xlrec;
 
 		xlrec.node = index->rd_node;
-		xlrec.blkno = BufferGetBlockNumber(rootbuffer);
+		xlrec.blkno = rootblock;
 
 		rdata.data = (char *) &xlrec;
 		rdata.len = sizeof(RelFileNode);
@@ -210,6 +219,7 @@ gistbuild(PG_FUNCTION_ARGS)
 		PageSetLSN(rootpage, GetXLogRecPtrForTemp());
 
 	UnlockReleaseBuffer(rootbuffer);
+	UnlockReleaseBuffer(metabuffer);
 
 	END_CRIT_SECTION();
 
@@ -251,6 +261,24 @@ gistbuild(PG_FUNCTION_ARGS)
 	PG_RETURN_POINTER(result);
 }
 
+/*
+ * Initialize metabuffer.
+ */
+static void
+GistInitMetabuffer(Relation index, Buffer buffer, BlockNumber root)
+{
+	GistMetaPageData   *meta;
+	Page		page = BufferGetPage(buffer);
+
+	GISTInitBuffer(buffer, 0);
+	MetapageInit(index, page);
+
+	meta = GistPageGetMeta(page);
+	meta->gist_magic = GIST_MAGIC;
+	meta->gist_version = GIST_VERSION;
+	meta->gist_root = root;
+}
+
 /*
  * Validator for "buffering" reloption on GiST indexes. Allows "on", "off"
  * and "auto" values.