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9c02cf5661
The initial value of the nbtree stack downlink block number field recorded during an initial descent of the tree wasn't actually used. Both _bt_getstackbuf() callers overwrote the value with their own value. Remove the block number field from the stack struct, and add a child block number argument to _bt_getstackbuf() in its place. This makes the overall design of _bt_getstackbuf() clearer. Author: Peter Geoghegan Reviewed-By: Anastasia Lubennikova Discussion: https://postgr.es/m/CAH2-Wzmx+UbXt2YNOUCZ-a04VdXU=S=OHuAuD7Z8uQq-PXTYUg@mail.gmail.com
826 lines
34 KiB
C
826 lines
34 KiB
C
/*-------------------------------------------------------------------------
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*
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* nbtree.h
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* header file for postgres btree access method implementation.
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*
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*
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* Portions Copyright (c) 1996-2019, 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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* src/include/access/nbtree.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef NBTREE_H
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#define NBTREE_H
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#include "access/amapi.h"
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#include "access/itup.h"
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#include "access/sdir.h"
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#include "access/xlogreader.h"
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#include "catalog/pg_index.h"
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#include "lib/stringinfo.h"
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#include "storage/bufmgr.h"
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#include "storage/shm_toc.h"
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/* There's room for a 16-bit vacuum cycle ID in BTPageOpaqueData */
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typedef uint16 BTCycleId;
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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. This is used to do forward/backward
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* index scans. The next-page link is also critical for recovery when
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* a search has navigated to the wrong page due to concurrent page splits
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* or deletions; see src/backend/access/nbtree/README for more info.
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*
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* In addition, we store the page's btree level (counting upwards from
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* zero at a leaf page) as well as some flag bits indicating the page type
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* and status. If the page is deleted, we replace the level with the
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* next-transaction-ID value indicating when it is safe to reclaim the page.
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*
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* We also store a "vacuum cycle ID". When a page is split while VACUUM is
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* processing the index, a nonzero value associated with the VACUUM run is
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* stored into both halves of the split page. (If VACUUM is not running,
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* both pages receive zero cycleids.) This allows VACUUM to detect whether
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* a page was split since it started, with a small probability of false match
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* if the page was last split some exact multiple of MAX_BT_CYCLE_ID VACUUMs
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* ago. Also, during a split, the BTP_SPLIT_END flag is cleared in the left
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* (original) page, and set in the right page, but only if the next page
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* to its right has a different cycleid.
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*
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* NOTE: the BTP_LEAF flag bit is redundant since level==0 could be tested
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* instead.
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*/
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typedef struct BTPageOpaqueData
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{
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BlockNumber btpo_prev; /* left sibling, or P_NONE if leftmost */
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BlockNumber btpo_next; /* right sibling, or P_NONE if rightmost */
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union
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{
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uint32 level; /* tree level --- zero for leaf pages */
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TransactionId xact; /* next transaction ID, if deleted */
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} btpo;
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uint16 btpo_flags; /* flag bits, see below */
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BTCycleId btpo_cycleid; /* vacuum cycle ID of latest split */
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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) /* leaf page, i.e. not internal page */
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#define BTP_ROOT (1 << 1) /* root page (has no parent) */
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#define BTP_DELETED (1 << 2) /* page has been deleted from tree */
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#define BTP_META (1 << 3) /* meta-page */
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#define BTP_HALF_DEAD (1 << 4) /* empty, but still in tree */
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#define BTP_SPLIT_END (1 << 5) /* rightmost page of split group */
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#define BTP_HAS_GARBAGE (1 << 6) /* page has LP_DEAD tuples */
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#define BTP_INCOMPLETE_SPLIT (1 << 7) /* right sibling's downlink is missing */
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/*
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* The max allowed value of a cycle ID is a bit less than 64K. This is
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* for convenience of pg_filedump and similar utilities: we want to use
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* the last 2 bytes of special space as an index type indicator, and
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* restricting cycle ID lets btree use that space for vacuum cycle IDs
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* while still allowing index type to be identified.
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*/
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#define MAX_BT_CYCLE_ID 0xFF7F
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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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* We also point to the "fast" root, which is the current effective root;
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* see README for discussion.
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*/
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typedef struct BTMetaPageData
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{
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uint32 btm_magic; /* should contain BTREE_MAGIC */
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uint32 btm_version; /* nbtree version (always <= BTREE_VERSION) */
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BlockNumber btm_root; /* current root location */
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uint32 btm_level; /* tree level of the root page */
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BlockNumber btm_fastroot; /* current "fast" root location */
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uint32 btm_fastlevel; /* tree level of the "fast" root page */
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/* remaining fields only valid when btm_version >= BTREE_NOVAC_VERSION */
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TransactionId btm_oldest_btpo_xact; /* oldest btpo_xact among all deleted
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* pages */
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float8 btm_last_cleanup_num_heap_tuples; /* number of heap tuples
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* during last cleanup */
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} BTMetaPageData;
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#define BTPageGetMeta(p) \
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((BTMetaPageData *) PageGetContents(p))
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/*
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* The current Btree version is 4. That's what you'll get when you create
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* a new index.
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*
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* Btree version 3 was used in PostgreSQL v11. It is mostly the same as
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* version 4, but heap TIDs were not part of the keyspace. Index tuples
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* with duplicate keys could be stored in any order. We continue to
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* support reading and writing Btree versions 2 and 3, so that they don't
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* need to be immediately re-indexed at pg_upgrade. In order to get the
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* new heapkeyspace semantics, however, a REINDEX is needed.
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*
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* Btree version 2 is mostly the same as version 3. There are two new
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* fields in the metapage that were introduced in version 3. A version 2
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* metapage will be automatically upgraded to version 3 on the first
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* insert to it. INCLUDE indexes cannot use version 2.
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*/
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#define BTREE_METAPAGE 0 /* first page is meta */
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#define BTREE_MAGIC 0x053162 /* magic number in metapage */
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#define BTREE_VERSION 4 /* current version number */
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#define BTREE_MIN_VERSION 2 /* minimal supported version number */
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#define BTREE_NOVAC_VERSION 3 /* minimal version with all meta fields */
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/*
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* Maximum size of a btree index entry, including its tuple header.
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*
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* We actually need to be able to fit three items on every page,
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* so restrict any one item to 1/3 the per-page available space.
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*
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* There are rare cases where _bt_truncate() will need to enlarge
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* a heap index tuple to make space for a tiebreaker heap TID
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* attribute, which we account for here.
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*/
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#define BTMaxItemSize(page) \
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MAXALIGN_DOWN((PageGetPageSize(page) - \
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MAXALIGN(SizeOfPageHeaderData + \
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3*sizeof(ItemIdData) + \
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3*sizeof(ItemPointerData)) - \
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MAXALIGN(sizeof(BTPageOpaqueData))) / 3)
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#define BTMaxItemSizeNoHeapTid(page) \
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MAXALIGN_DOWN((PageGetPageSize(page) - \
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MAXALIGN(SizeOfPageHeaderData + 3*sizeof(ItemIdData)) - \
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MAXALIGN(sizeof(BTPageOpaqueData))) / 3)
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/*
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* The leaf-page fillfactor defaults to 90% but is user-adjustable.
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* For pages above the leaf level, we use a fixed 70% fillfactor.
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* The fillfactor is applied during index build and when splitting
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* a rightmost page; when splitting non-rightmost pages we try to
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* divide the data equally. When splitting a page that's entirely
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* filled with a single value (duplicates), the effective leaf-page
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* fillfactor is 96%, regardless of whether the page is a rightmost
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* page.
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*/
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#define BTREE_MIN_FILLFACTOR 10
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#define BTREE_DEFAULT_FILLFACTOR 90
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#define BTREE_NONLEAF_FILLFACTOR 70
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#define BTREE_SINGLEVAL_FILLFACTOR 96
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/*
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* In general, the btree code tries to localize its knowledge about
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* page layout to a couple of routines. However, we need a special
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* value to indicate "no page number" in those places where we expect
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* page numbers. We can use zero for this because we never need to
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* make a pointer to the metadata page.
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*/
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#define P_NONE 0
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/*
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* Macros to test whether a page is leftmost or rightmost on its tree level,
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* as well as other state info kept in the opaque data.
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*/
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#define P_LEFTMOST(opaque) ((opaque)->btpo_prev == P_NONE)
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#define P_RIGHTMOST(opaque) ((opaque)->btpo_next == P_NONE)
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#define P_ISLEAF(opaque) (((opaque)->btpo_flags & BTP_LEAF) != 0)
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#define P_ISROOT(opaque) (((opaque)->btpo_flags & BTP_ROOT) != 0)
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#define P_ISDELETED(opaque) (((opaque)->btpo_flags & BTP_DELETED) != 0)
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#define P_ISMETA(opaque) (((opaque)->btpo_flags & BTP_META) != 0)
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#define P_ISHALFDEAD(opaque) (((opaque)->btpo_flags & BTP_HALF_DEAD) != 0)
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#define P_IGNORE(opaque) (((opaque)->btpo_flags & (BTP_DELETED|BTP_HALF_DEAD)) != 0)
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#define P_HAS_GARBAGE(opaque) (((opaque)->btpo_flags & BTP_HAS_GARBAGE) != 0)
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#define P_INCOMPLETE_SPLIT(opaque) (((opaque)->btpo_flags & BTP_INCOMPLETE_SPLIT) != 0)
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/*
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* Lehman and Yao's algorithm requires a ``high key'' on every non-rightmost
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* page. The high key is not a tuple that is used to visit the heap. It is
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* a pivot tuple (see "Notes on B-Tree tuple format" below for definition).
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* The high key on a page is required to be greater than or equal to any
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* other key that appears on the page. If we find ourselves trying to
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* insert a key that is strictly > high key, we know we need to move right
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* (this should only happen if the page was split since we examined the
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* parent page).
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*
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* Our insertion algorithm guarantees that we can use the initial least key
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* on our right sibling as the high key. Once a page is created, its high
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* key changes only if the page is split.
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*
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* On a non-rightmost page, the high key lives in item 1 and data items
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* start in item 2. Rightmost pages have no high key, so we store data
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* items beginning in item 1.
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*/
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#define P_HIKEY ((OffsetNumber) 1)
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#define P_FIRSTKEY ((OffsetNumber) 2)
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#define P_FIRSTDATAKEY(opaque) (P_RIGHTMOST(opaque) ? P_HIKEY : P_FIRSTKEY)
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/*
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* Notes on B-Tree tuple format, and key and non-key attributes:
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*
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* INCLUDE B-Tree indexes have non-key attributes. These are extra
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* attributes that may be returned by index-only scans, but do not influence
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* the order of items in the index (formally, non-key attributes are not
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* considered to be part of the key space). Non-key attributes are only
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* present in leaf index tuples whose item pointers actually point to heap
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* tuples (non-pivot tuples). _bt_check_natts() enforces the rules
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* described here.
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*
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* Non-pivot tuple format:
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*
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* t_tid | t_info | key values | INCLUDE columns, if any
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*
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* t_tid points to the heap TID, which is a tiebreaker key column as of
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* BTREE_VERSION 4. Currently, the INDEX_ALT_TID_MASK status bit is never
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* set for non-pivot tuples.
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*
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* All other types of index tuples ("pivot" tuples) only have key columns,
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* since pivot tuples only exist to represent how the key space is
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* separated. In general, any B-Tree index that has more than one level
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* (i.e. any index that does not just consist of a metapage and a single
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* leaf root page) must have some number of pivot tuples, since pivot
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* tuples are used for traversing the tree. Suffix truncation can omit
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* trailing key columns when a new pivot is formed, which makes minus
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* infinity their logical value. Since BTREE_VERSION 4 indexes treat heap
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* TID as a trailing key column that ensures that all index tuples are
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* physically unique, it is necessary to represent heap TID as a trailing
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* key column in pivot tuples, though very often this can be truncated
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* away, just like any other key column. (Actually, the heap TID is
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* omitted rather than truncated, since its representation is different to
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* the non-pivot representation.)
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*
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* Pivot tuple format:
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*
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* t_tid | t_info | key values | [heap TID]
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*
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* We store the number of columns present inside pivot tuples by abusing
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* their t_tid offset field, since pivot tuples never need to store a real
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* offset (downlinks only need to store a block number in t_tid). The
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* offset field only stores the number of columns/attributes when the
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* INDEX_ALT_TID_MASK bit is set, which doesn't count the trailing heap
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* TID column sometimes stored in pivot tuples -- that's represented by
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* the presence of BT_HEAP_TID_ATTR. The INDEX_ALT_TID_MASK bit in t_info
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* is always set on BTREE_VERSION 4. BT_HEAP_TID_ATTR can only be set on
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* BTREE_VERSION 4.
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*
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* In version 3 indexes, the INDEX_ALT_TID_MASK flag might not be set in
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* pivot tuples. In that case, the number of key columns is implicitly
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* the same as the number of key columns in the index. It is not usually
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* set on version 2 indexes, which predate the introduction of INCLUDE
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* indexes. (Only explicitly truncated pivot tuples explicitly represent
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* the number of key columns on versions 2 and 3, whereas all pivot tuples
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* are formed using truncation on version 4. A version 2 index will have
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* it set for an internal page negative infinity item iff internal page
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* split occurred after upgrade to Postgres 11+.)
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*
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* The 12 least significant offset bits from t_tid are used to represent
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* the number of columns in INDEX_ALT_TID_MASK tuples, leaving 4 status
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* bits (BT_RESERVED_OFFSET_MASK bits), 3 of which that are reserved for
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* future use. BT_N_KEYS_OFFSET_MASK should be large enough to store any
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* number of columns/attributes <= INDEX_MAX_KEYS.
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*
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* Note well: The macros that deal with the number of attributes in tuples
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* assume that a tuple with INDEX_ALT_TID_MASK set must be a pivot tuple,
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* and that a tuple without INDEX_ALT_TID_MASK set must be a non-pivot
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* tuple (or must have the same number of attributes as the index has
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* generally in the case of !heapkeyspace indexes). They will need to be
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* updated if non-pivot tuples ever get taught to use INDEX_ALT_TID_MASK
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* for something else.
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*/
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#define INDEX_ALT_TID_MASK INDEX_AM_RESERVED_BIT
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/* Item pointer offset bits */
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#define BT_RESERVED_OFFSET_MASK 0xF000
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#define BT_N_KEYS_OFFSET_MASK 0x0FFF
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#define BT_HEAP_TID_ATTR 0x1000
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/* Get/set downlink block number */
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#define BTreeInnerTupleGetDownLink(itup) \
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ItemPointerGetBlockNumberNoCheck(&((itup)->t_tid))
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#define BTreeInnerTupleSetDownLink(itup, blkno) \
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ItemPointerSetBlockNumber(&((itup)->t_tid), (blkno))
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/*
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* Get/set leaf page highkey's link. During the second phase of deletion, the
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* target leaf page's high key may point to an ancestor page (at all other
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* times, the leaf level high key's link is not used). See the nbtree README
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* for full details.
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*/
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#define BTreeTupleGetTopParent(itup) \
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ItemPointerGetBlockNumberNoCheck(&((itup)->t_tid))
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#define BTreeTupleSetTopParent(itup, blkno) \
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do { \
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ItemPointerSetBlockNumber(&((itup)->t_tid), (blkno)); \
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BTreeTupleSetNAtts((itup), 0); \
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} while(0)
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/*
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* Get/set number of attributes within B-tree index tuple.
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*
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* Note that this does not include an implicit tiebreaker heap TID
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* attribute, if any. Note also that the number of key attributes must be
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* explicitly represented in all heapkeyspace pivot tuples.
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*/
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#define BTreeTupleGetNAtts(itup, rel) \
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( \
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(itup)->t_info & INDEX_ALT_TID_MASK ? \
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( \
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ItemPointerGetOffsetNumberNoCheck(&(itup)->t_tid) & BT_N_KEYS_OFFSET_MASK \
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) \
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: \
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IndexRelationGetNumberOfAttributes(rel) \
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)
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#define BTreeTupleSetNAtts(itup, n) \
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do { \
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(itup)->t_info |= INDEX_ALT_TID_MASK; \
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ItemPointerSetOffsetNumber(&(itup)->t_tid, (n) & BT_N_KEYS_OFFSET_MASK); \
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} while(0)
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/*
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* Get tiebreaker heap TID attribute, if any. Macro works with both pivot
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* and non-pivot tuples, despite differences in how heap TID is represented.
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*/
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#define BTreeTupleGetHeapTID(itup) \
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( \
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(itup)->t_info & INDEX_ALT_TID_MASK && \
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(ItemPointerGetOffsetNumberNoCheck(&(itup)->t_tid) & BT_HEAP_TID_ATTR) != 0 ? \
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( \
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(ItemPointer) (((char *) (itup) + IndexTupleSize(itup)) - \
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sizeof(ItemPointerData)) \
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) \
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: (itup)->t_info & INDEX_ALT_TID_MASK ? NULL : (ItemPointer) &((itup)->t_tid) \
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)
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/*
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* Set the heap TID attribute for a tuple that uses the INDEX_ALT_TID_MASK
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* representation (currently limited to pivot tuples)
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*/
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#define BTreeTupleSetAltHeapTID(itup) \
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do { \
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Assert((itup)->t_info & INDEX_ALT_TID_MASK); \
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ItemPointerSetOffsetNumber(&(itup)->t_tid, \
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ItemPointerGetOffsetNumberNoCheck(&(itup)->t_tid) | BT_HEAP_TID_ATTR); \
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} while(0)
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/*
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* Operator strategy numbers for B-tree have been moved to access/stratnum.h,
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* because many places need to use them in ScanKeyInit() calls.
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*
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* The strategy numbers are chosen so that we can commute them by
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* subtraction, thus:
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*/
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#define BTCommuteStrategyNumber(strat) (BTMaxStrategyNumber + 1 - (strat))
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/*
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* When a new operator class is declared, we require that the user
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* supply us with an amproc procedure (BTORDER_PROC) for determining
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* whether, for two keys a and b, a < b, a = b, or a > b. This routine
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* must return < 0, 0, > 0, respectively, in these three cases.
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*
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* To facilitate accelerated sorting, an operator class may choose to
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* offer a second procedure (BTSORTSUPPORT_PROC). For full details, see
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* src/include/utils/sortsupport.h.
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*
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* To support window frames defined by "RANGE offset PRECEDING/FOLLOWING",
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* an operator class may choose to offer a third amproc procedure
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* (BTINRANGE_PROC), independently of whether it offers sortsupport.
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* For full details, see doc/src/sgml/btree.sgml.
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*/
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#define BTORDER_PROC 1
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#define BTSORTSUPPORT_PROC 2
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#define BTINRANGE_PROC 3
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#define BTNProcs 3
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/*
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* We need to be able to tell the difference between read and write
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* requests for pages, in order to do locking correctly.
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*/
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#define BT_READ BUFFER_LOCK_SHARE
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#define BT_WRITE BUFFER_LOCK_EXCLUSIVE
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/*
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* BTStackData -- As we descend a tree, we push the location of pivot
|
|
* tuples whose downlink we are about to follow onto a private stack. If
|
|
* we split a leaf, we use this stack to walk back up the tree and insert
|
|
* data into its parent page at the correct location. We may also have to
|
|
* recursively split a grandparent of the leaf page (and so on).
|
|
*/
|
|
typedef struct BTStackData
|
|
{
|
|
BlockNumber bts_blkno;
|
|
OffsetNumber bts_offset;
|
|
struct BTStackData *bts_parent;
|
|
} BTStackData;
|
|
|
|
typedef BTStackData *BTStack;
|
|
|
|
/*
|
|
* BTScanInsertData is the btree-private state needed to find an initial
|
|
* position for an indexscan, or to insert new tuples -- an "insertion
|
|
* scankey" (not to be confused with a search scankey). It's used to descend
|
|
* a B-Tree using _bt_search.
|
|
*
|
|
* heapkeyspace indicates if we expect all keys in the index to be physically
|
|
* unique because heap TID is used as a tiebreaker attribute, and if index may
|
|
* have truncated key attributes in pivot tuples. This is actually a property
|
|
* of the index relation itself (not an indexscan). heapkeyspace indexes are
|
|
* indexes whose version is >= version 4. It's convenient to keep this close
|
|
* by, rather than accessing the metapage repeatedly.
|
|
*
|
|
* anynullkeys indicates if any of the keys had NULL value when scankey was
|
|
* built from index tuple (note that already-truncated tuple key attributes
|
|
* set NULL as a placeholder key value, which also affects value of
|
|
* anynullkeys). This is a convenience for unique index non-pivot tuple
|
|
* insertion, which usually temporarily unsets scantid, but shouldn't iff
|
|
* anynullkeys is true. Value generally matches non-pivot tuple's HasNulls
|
|
* bit, but may not when inserting into an INCLUDE index (tuple header value
|
|
* is affected by the NULL-ness of both key and non-key attributes).
|
|
*
|
|
* When nextkey is false (the usual case), _bt_search and _bt_binsrch will
|
|
* locate the first item >= scankey. When nextkey is true, they will locate
|
|
* the first item > scan key.
|
|
*
|
|
* pivotsearch is set to true by callers that want to re-find a leaf page
|
|
* using a scankey built from a leaf page's high key. Most callers set this
|
|
* to false.
|
|
*
|
|
* scantid is the heap TID that is used as a final tiebreaker attribute. It
|
|
* is set to NULL when index scan doesn't need to find a position for a
|
|
* specific physical tuple. Must be set when inserting new tuples into
|
|
* heapkeyspace indexes, since every tuple in the tree unambiguously belongs
|
|
* in one exact position (it's never set with !heapkeyspace indexes, though).
|
|
* Despite the representational difference, nbtree search code considers
|
|
* scantid to be just another insertion scankey attribute.
|
|
*
|
|
* scankeys is an array of scan key entries for attributes that are compared
|
|
* before scantid (user-visible attributes). keysz is the size of the array.
|
|
* During insertion, there must be a scan key for every attribute, but when
|
|
* starting a regular index scan some can be omitted. The array is used as a
|
|
* flexible array member, though it's sized in a way that makes it possible to
|
|
* use stack allocations. See nbtree/README for full details.
|
|
*/
|
|
typedef struct BTScanInsertData
|
|
{
|
|
bool heapkeyspace;
|
|
bool anynullkeys;
|
|
bool nextkey;
|
|
bool pivotsearch;
|
|
ItemPointer scantid; /* tiebreaker for scankeys */
|
|
int keysz; /* Size of scankeys array */
|
|
ScanKeyData scankeys[INDEX_MAX_KEYS]; /* Must appear last */
|
|
} BTScanInsertData;
|
|
|
|
typedef BTScanInsertData *BTScanInsert;
|
|
|
|
/*
|
|
* BTInsertStateData is a working area used during insertion.
|
|
*
|
|
* This is filled in after descending the tree to the first leaf page the new
|
|
* tuple might belong on. Tracks the current position while performing
|
|
* uniqueness check, before we have determined which exact page to insert
|
|
* to.
|
|
*
|
|
* (This should be private to nbtinsert.c, but it's also used by
|
|
* _bt_binsrch_insert)
|
|
*/
|
|
typedef struct BTInsertStateData
|
|
{
|
|
IndexTuple itup; /* Item we're inserting */
|
|
Size itemsz; /* Size of itup -- should be MAXALIGN()'d */
|
|
BTScanInsert itup_key; /* Insertion scankey */
|
|
|
|
/* Buffer containing leaf page we're likely to insert itup on */
|
|
Buffer buf;
|
|
|
|
/*
|
|
* Cache of bounds within the current buffer. Only used for insertions
|
|
* where _bt_check_unique is called. See _bt_binsrch_insert and
|
|
* _bt_findinsertloc for details.
|
|
*/
|
|
bool bounds_valid;
|
|
OffsetNumber low;
|
|
OffsetNumber stricthigh;
|
|
} BTInsertStateData;
|
|
|
|
typedef BTInsertStateData *BTInsertState;
|
|
|
|
/*
|
|
* BTScanOpaqueData is the btree-private state needed for an indexscan.
|
|
* This consists of preprocessed scan keys (see _bt_preprocess_keys() for
|
|
* details of the preprocessing), information about the current location
|
|
* of the scan, and information about the marked location, if any. (We use
|
|
* BTScanPosData to represent the data needed for each of current and marked
|
|
* locations.) In addition we can remember some known-killed index entries
|
|
* that must be marked before we can move off the current page.
|
|
*
|
|
* Index scans work a page at a time: we pin and read-lock the page, identify
|
|
* all the matching items on the page and save them in BTScanPosData, then
|
|
* release the read-lock while returning the items to the caller for
|
|
* processing. This approach minimizes lock/unlock traffic. Note that we
|
|
* keep the pin on the index page until the caller is done with all the items
|
|
* (this is needed for VACUUM synchronization, see nbtree/README). When we
|
|
* are ready to step to the next page, if the caller has told us any of the
|
|
* items were killed, we re-lock the page to mark them killed, then unlock.
|
|
* Finally we drop the pin and step to the next page in the appropriate
|
|
* direction.
|
|
*
|
|
* If we are doing an index-only scan, we save the entire IndexTuple for each
|
|
* matched item, otherwise only its heap TID and offset. The IndexTuples go
|
|
* into a separate workspace array; each BTScanPosItem stores its tuple's
|
|
* offset within that array.
|
|
*/
|
|
|
|
typedef struct BTScanPosItem /* what we remember about each match */
|
|
{
|
|
ItemPointerData heapTid; /* TID of referenced heap item */
|
|
OffsetNumber indexOffset; /* index item's location within page */
|
|
LocationIndex tupleOffset; /* IndexTuple's offset in workspace, if any */
|
|
} BTScanPosItem;
|
|
|
|
typedef struct BTScanPosData
|
|
{
|
|
Buffer buf; /* if valid, the buffer is pinned */
|
|
|
|
XLogRecPtr lsn; /* pos in the WAL stream when page was read */
|
|
BlockNumber currPage; /* page referenced by items array */
|
|
BlockNumber nextPage; /* page's right link when we scanned it */
|
|
|
|
/*
|
|
* moreLeft and moreRight track whether we think there may be matching
|
|
* index entries to the left and right of the current page, respectively.
|
|
* We can clear the appropriate one of these flags when _bt_checkkeys()
|
|
* returns continuescan = false.
|
|
*/
|
|
bool moreLeft;
|
|
bool moreRight;
|
|
|
|
/*
|
|
* If we are doing an index-only scan, nextTupleOffset is the first free
|
|
* location in the associated tuple storage workspace.
|
|
*/
|
|
int nextTupleOffset;
|
|
|
|
/*
|
|
* The items array is always ordered in index order (ie, increasing
|
|
* indexoffset). When scanning backwards it is convenient to fill the
|
|
* array back-to-front, so we start at the last slot and fill downwards.
|
|
* Hence we need both a first-valid-entry and a last-valid-entry counter.
|
|
* itemIndex is a cursor showing which entry was last returned to caller.
|
|
*/
|
|
int firstItem; /* first valid index in items[] */
|
|
int lastItem; /* last valid index in items[] */
|
|
int itemIndex; /* current index in items[] */
|
|
|
|
BTScanPosItem items[MaxIndexTuplesPerPage]; /* MUST BE LAST */
|
|
} BTScanPosData;
|
|
|
|
typedef BTScanPosData *BTScanPos;
|
|
|
|
#define BTScanPosIsPinned(scanpos) \
|
|
( \
|
|
AssertMacro(BlockNumberIsValid((scanpos).currPage) || \
|
|
!BufferIsValid((scanpos).buf)), \
|
|
BufferIsValid((scanpos).buf) \
|
|
)
|
|
#define BTScanPosUnpin(scanpos) \
|
|
do { \
|
|
ReleaseBuffer((scanpos).buf); \
|
|
(scanpos).buf = InvalidBuffer; \
|
|
} while (0)
|
|
#define BTScanPosUnpinIfPinned(scanpos) \
|
|
do { \
|
|
if (BTScanPosIsPinned(scanpos)) \
|
|
BTScanPosUnpin(scanpos); \
|
|
} while (0)
|
|
|
|
#define BTScanPosIsValid(scanpos) \
|
|
( \
|
|
AssertMacro(BlockNumberIsValid((scanpos).currPage) || \
|
|
!BufferIsValid((scanpos).buf)), \
|
|
BlockNumberIsValid((scanpos).currPage) \
|
|
)
|
|
#define BTScanPosInvalidate(scanpos) \
|
|
do { \
|
|
(scanpos).currPage = InvalidBlockNumber; \
|
|
(scanpos).nextPage = InvalidBlockNumber; \
|
|
(scanpos).buf = InvalidBuffer; \
|
|
(scanpos).lsn = InvalidXLogRecPtr; \
|
|
(scanpos).nextTupleOffset = 0; \
|
|
} while (0);
|
|
|
|
/* We need one of these for each equality-type SK_SEARCHARRAY scan key */
|
|
typedef struct BTArrayKeyInfo
|
|
{
|
|
int scan_key; /* index of associated key in arrayKeyData */
|
|
int cur_elem; /* index of current element in elem_values */
|
|
int mark_elem; /* index of marked element in elem_values */
|
|
int num_elems; /* number of elems in current array value */
|
|
Datum *elem_values; /* array of num_elems Datums */
|
|
} BTArrayKeyInfo;
|
|
|
|
typedef struct BTScanOpaqueData
|
|
{
|
|
/* these fields are set by _bt_preprocess_keys(): */
|
|
bool qual_ok; /* false if qual can never be satisfied */
|
|
int numberOfKeys; /* number of preprocessed scan keys */
|
|
ScanKey keyData; /* array of preprocessed scan keys */
|
|
|
|
/* workspace for SK_SEARCHARRAY support */
|
|
ScanKey arrayKeyData; /* modified copy of scan->keyData */
|
|
int numArrayKeys; /* number of equality-type array keys (-1 if
|
|
* there are any unsatisfiable array keys) */
|
|
int arrayKeyCount; /* count indicating number of array scan keys
|
|
* processed */
|
|
BTArrayKeyInfo *arrayKeys; /* info about each equality-type array key */
|
|
MemoryContext arrayContext; /* scan-lifespan context for array data */
|
|
|
|
/* info about killed items if any (killedItems is NULL if never used) */
|
|
int *killedItems; /* currPos.items indexes of killed items */
|
|
int numKilled; /* number of currently stored items */
|
|
|
|
/*
|
|
* If we are doing an index-only scan, these are the tuple storage
|
|
* workspaces for the currPos and markPos respectively. Each is of size
|
|
* BLCKSZ, so it can hold as much as a full page's worth of tuples.
|
|
*/
|
|
char *currTuples; /* tuple storage for currPos */
|
|
char *markTuples; /* tuple storage for markPos */
|
|
|
|
/*
|
|
* If the marked position is on the same page as current position, we
|
|
* don't use markPos, but just keep the marked itemIndex in markItemIndex
|
|
* (all the rest of currPos is valid for the mark position). Hence, to
|
|
* determine if there is a mark, first look at markItemIndex, then at
|
|
* markPos.
|
|
*/
|
|
int markItemIndex; /* itemIndex, or -1 if not valid */
|
|
|
|
/* keep these last in struct for efficiency */
|
|
BTScanPosData currPos; /* current position data */
|
|
BTScanPosData markPos; /* marked position, if any */
|
|
} BTScanOpaqueData;
|
|
|
|
typedef BTScanOpaqueData *BTScanOpaque;
|
|
|
|
/*
|
|
* We use some private sk_flags bits in preprocessed scan keys. We're allowed
|
|
* to use bits 16-31 (see skey.h). The uppermost bits are copied from the
|
|
* index's indoption[] array entry for the index attribute.
|
|
*/
|
|
#define SK_BT_REQFWD 0x00010000 /* required to continue forward scan */
|
|
#define SK_BT_REQBKWD 0x00020000 /* required to continue backward scan */
|
|
#define SK_BT_INDOPTION_SHIFT 24 /* must clear the above bits */
|
|
#define SK_BT_DESC (INDOPTION_DESC << SK_BT_INDOPTION_SHIFT)
|
|
#define SK_BT_NULLS_FIRST (INDOPTION_NULLS_FIRST << SK_BT_INDOPTION_SHIFT)
|
|
|
|
/*
|
|
* Constant definition for progress reporting. Phase numbers must match
|
|
* btbuildphasename.
|
|
*/
|
|
/* PROGRESS_CREATEIDX_SUBPHASE_INITIALIZE is 1 (see progress.h) */
|
|
#define PROGRESS_BTREE_PHASE_INDEXBUILD_TABLESCAN 2
|
|
#define PROGRESS_BTREE_PHASE_PERFORMSORT_1 3
|
|
#define PROGRESS_BTREE_PHASE_PERFORMSORT_2 4
|
|
#define PROGRESS_BTREE_PHASE_LEAF_LOAD 5
|
|
|
|
/*
|
|
* external entry points for btree, in nbtree.c
|
|
*/
|
|
extern void btbuildempty(Relation index);
|
|
extern bool btinsert(Relation rel, Datum *values, bool *isnull,
|
|
ItemPointer ht_ctid, Relation heapRel,
|
|
IndexUniqueCheck checkUnique,
|
|
struct IndexInfo *indexInfo);
|
|
extern IndexScanDesc btbeginscan(Relation rel, int nkeys, int norderbys);
|
|
extern Size btestimateparallelscan(void);
|
|
extern void btinitparallelscan(void *target);
|
|
extern bool btgettuple(IndexScanDesc scan, ScanDirection dir);
|
|
extern int64 btgetbitmap(IndexScanDesc scan, TIDBitmap *tbm);
|
|
extern void btrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
|
|
ScanKey orderbys, int norderbys);
|
|
extern void btparallelrescan(IndexScanDesc scan);
|
|
extern void btendscan(IndexScanDesc scan);
|
|
extern void btmarkpos(IndexScanDesc scan);
|
|
extern void btrestrpos(IndexScanDesc scan);
|
|
extern IndexBulkDeleteResult *btbulkdelete(IndexVacuumInfo *info,
|
|
IndexBulkDeleteResult *stats,
|
|
IndexBulkDeleteCallback callback,
|
|
void *callback_state);
|
|
extern IndexBulkDeleteResult *btvacuumcleanup(IndexVacuumInfo *info,
|
|
IndexBulkDeleteResult *stats);
|
|
extern bool btcanreturn(Relation index, int attno);
|
|
|
|
/*
|
|
* prototypes for internal functions in nbtree.c
|
|
*/
|
|
extern bool _bt_parallel_seize(IndexScanDesc scan, BlockNumber *pageno);
|
|
extern void _bt_parallel_release(IndexScanDesc scan, BlockNumber scan_page);
|
|
extern void _bt_parallel_done(IndexScanDesc scan);
|
|
extern void _bt_parallel_advance_array_keys(IndexScanDesc scan);
|
|
|
|
/*
|
|
* prototypes for functions in nbtinsert.c
|
|
*/
|
|
extern bool _bt_doinsert(Relation rel, IndexTuple itup,
|
|
IndexUniqueCheck checkUnique, Relation heapRel);
|
|
extern Buffer _bt_getstackbuf(Relation rel, BTStack stack, BlockNumber child);
|
|
extern void _bt_finish_split(Relation rel, Buffer bbuf, BTStack stack);
|
|
|
|
/*
|
|
* prototypes for functions in nbtsplitloc.c
|
|
*/
|
|
extern OffsetNumber _bt_findsplitloc(Relation rel, Page page,
|
|
OffsetNumber newitemoff, Size newitemsz, IndexTuple newitem,
|
|
bool *newitemonleft);
|
|
|
|
/*
|
|
* prototypes for functions in nbtpage.c
|
|
*/
|
|
extern void _bt_initmetapage(Page page, BlockNumber rootbknum, uint32 level);
|
|
extern void _bt_update_meta_cleanup_info(Relation rel,
|
|
TransactionId oldestBtpoXact, float8 numHeapTuples);
|
|
extern void _bt_upgrademetapage(Page page);
|
|
extern Buffer _bt_getroot(Relation rel, int access);
|
|
extern Buffer _bt_gettrueroot(Relation rel);
|
|
extern int _bt_getrootheight(Relation rel);
|
|
extern bool _bt_heapkeyspace(Relation rel);
|
|
extern void _bt_checkpage(Relation rel, Buffer buf);
|
|
extern Buffer _bt_getbuf(Relation rel, BlockNumber blkno, int access);
|
|
extern Buffer _bt_relandgetbuf(Relation rel, Buffer obuf,
|
|
BlockNumber blkno, int access);
|
|
extern void _bt_relbuf(Relation rel, Buffer buf);
|
|
extern void _bt_pageinit(Page page, Size size);
|
|
extern bool _bt_page_recyclable(Page page);
|
|
extern void _bt_delitems_delete(Relation rel, Buffer buf,
|
|
OffsetNumber *itemnos, int nitems, Relation heapRel);
|
|
extern void _bt_delitems_vacuum(Relation rel, Buffer buf,
|
|
OffsetNumber *itemnos, int nitems,
|
|
BlockNumber lastBlockVacuumed);
|
|
extern int _bt_pagedel(Relation rel, Buffer buf);
|
|
|
|
/*
|
|
* prototypes for functions in nbtsearch.c
|
|
*/
|
|
extern BTStack _bt_search(Relation rel, BTScanInsert key, Buffer *bufP,
|
|
int access, Snapshot snapshot);
|
|
extern Buffer _bt_moveright(Relation rel, BTScanInsert key, Buffer buf,
|
|
bool forupdate, BTStack stack, int access, Snapshot snapshot);
|
|
extern OffsetNumber _bt_binsrch_insert(Relation rel, BTInsertState insertstate);
|
|
extern int32 _bt_compare(Relation rel, BTScanInsert key, Page page, OffsetNumber offnum);
|
|
extern bool _bt_first(IndexScanDesc scan, ScanDirection dir);
|
|
extern bool _bt_next(IndexScanDesc scan, ScanDirection dir);
|
|
extern Buffer _bt_get_endpoint(Relation rel, uint32 level, bool rightmost,
|
|
Snapshot snapshot);
|
|
|
|
/*
|
|
* prototypes for functions in nbtutils.c
|
|
*/
|
|
extern BTScanInsert _bt_mkscankey(Relation rel, IndexTuple itup);
|
|
extern void _bt_freestack(BTStack stack);
|
|
extern void _bt_preprocess_array_keys(IndexScanDesc scan);
|
|
extern void _bt_start_array_keys(IndexScanDesc scan, ScanDirection dir);
|
|
extern bool _bt_advance_array_keys(IndexScanDesc scan, ScanDirection dir);
|
|
extern void _bt_mark_array_keys(IndexScanDesc scan);
|
|
extern void _bt_restore_array_keys(IndexScanDesc scan);
|
|
extern void _bt_preprocess_keys(IndexScanDesc scan);
|
|
extern bool _bt_checkkeys(IndexScanDesc scan, IndexTuple tuple,
|
|
int tupnatts, ScanDirection dir, bool *continuescan);
|
|
extern void _bt_killitems(IndexScanDesc scan);
|
|
extern BTCycleId _bt_vacuum_cycleid(Relation rel);
|
|
extern BTCycleId _bt_start_vacuum(Relation rel);
|
|
extern void _bt_end_vacuum(Relation rel);
|
|
extern void _bt_end_vacuum_callback(int code, Datum arg);
|
|
extern Size BTreeShmemSize(void);
|
|
extern void BTreeShmemInit(void);
|
|
extern bytea *btoptions(Datum reloptions, bool validate);
|
|
extern bool btproperty(Oid index_oid, int attno,
|
|
IndexAMProperty prop, const char *propname,
|
|
bool *res, bool *isnull);
|
|
extern char *btbuildphasename(int64 phasenum);
|
|
extern IndexTuple _bt_truncate(Relation rel, IndexTuple lastleft,
|
|
IndexTuple firstright, BTScanInsert itup_key);
|
|
extern int _bt_keep_natts_fast(Relation rel, IndexTuple lastleft,
|
|
IndexTuple firstright);
|
|
extern bool _bt_check_natts(Relation rel, bool heapkeyspace, Page page,
|
|
OffsetNumber offnum);
|
|
extern void _bt_check_third_page(Relation rel, Relation heap,
|
|
bool needheaptidspace, Page page, IndexTuple newtup);
|
|
|
|
/*
|
|
* prototypes for functions in nbtvalidate.c
|
|
*/
|
|
extern bool btvalidate(Oid opclassoid);
|
|
|
|
/*
|
|
* prototypes for functions in nbtsort.c
|
|
*/
|
|
extern IndexBuildResult *btbuild(Relation heap, Relation index,
|
|
struct IndexInfo *indexInfo);
|
|
extern void _bt_parallel_build_main(dsm_segment *seg, shm_toc *toc);
|
|
|
|
#endif /* NBTREE_H */
|