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Clean up index/btree comments/macros, as approved.

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This commit is contained in:
Bruce Momjian
2001-02-22 21:48:49 +00:00
parent 660ca3e01c
commit 4f6c49fef0
6 changed files with 52 additions and 42 deletions
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47
src/include/access/nbtree.h
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@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: nbtree.h,v 1.52 2001/02/21 19:07:04 momjian Exp $
* $Id: nbtree.h,v 1.53 2001/02/22 21:48:49 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -21,8 +21,9 @@
/*
* BTPageOpaqueData -- At the end of every page, we store a pointer
* to both siblings in the tree. See Lehman and Yao's paper for more
* info. In addition, we need to know what sort of page this is
* to both siblings in the tree. This is used to do forward/backward
* index scans. See Lehman and Yao's paper for more
* info. In addition, we need to know what type of page this is
* (leaf or internal), and whether the page is available for reuse.
*
* We also store a back-link to the parent page, but this cannot be trusted
@@ -32,31 +33,28 @@
typedef struct BTPageOpaqueData
{
BlockNumber btpo_prev;
BlockNumber btpo_next;
BlockNumber btpo_parent;
uint16 btpo_flags;
BlockNumber btpo_prev; /* used for backward index scans */
BlockNumber btpo_next; /* used for forward index scans */
BlockNumber btpo_parent; /* pointer to parent, but not updated
on parent split */
uint16 btpo_flags; /* LEAF?, ROOT?, FREE?, META?, REORDER? */
} BTPageOpaqueData;
typedef BTPageOpaqueData *BTPageOpaque;
/* Bits defined in btpo_flags */
#define BTP_LEAF (1 << 0) /* It's a leaf page */
#define BTP_ROOT (1 << 1) /* It's the root page (has no parent) */
#define BTP_FREE (1 << 2) /* not currently used... */
#define BTP_META (1 << 3) /* Set in the meta-page only */
#define BTP_REORDER (1 << 4) /* items must be re-ordered */
#define BTP_LEAF (1 << 0) /* leaf page, if not internal page */
#define BTP_ROOT (1 << 1) /* root page (has no parent) */
#define BTP_FREE (1 << 2) /* page not in use */
#define BTP_META (1 << 3) /* meta-page */
#define BTP_REORDER (1 << 4) /* items need reordering */
#define BTREE_METAPAGE 0 /* first page is meta */
#define BTREE_MAGIC 0x053162
#define BTreeInvalidParent(opaque) \
(opaque->btpo_parent == InvalidBlockNumber || \
opaque->btpo_parent == BTREE_METAPAGE)
#define BTREE_VERSION 1
/*
* The Meta page is always the first page in the btree index.
* Its primary purpose is to point to the location of the btree root page.
*/
typedef struct BTMetaPageData
{
@@ -69,6 +67,15 @@ typedef struct BTMetaPageData
#define BTPageGetMeta(p) \
((BTMetaPageData *) &((PageHeader) p)->pd_linp[0])
#define BTREE_METAPAGE 0 /* first page is meta */
#define BTREE_MAGIC 0x053162 /* magic number of btree pages */
#define BTreeInvalidParent(opaque) \
(opaque->btpo_parent == InvalidBlockNumber || \
opaque->btpo_parent == BTREE_METAPAGE)
#define BTREE_VERSION 1
/*
* BTScanOpaqueData is used to remember which buffers we're currently
* examining in the scan. We keep these buffers pinned (but not locked,