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