/*-------------------------------------------------------------------------
*
* nbtree.h
* header file for postgres btree access method implementation.
*
*
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/access/nbtree.h
*
*-------------------------------------------------------------------------
*/
#ifndef NBTREE_H
#define NBTREE_H
#include "access/amapi.h"
#include "access/itup.h"
#include "access/sdir.h"
#include "access/tableam.h"
#include "access/xlogreader.h"
#include "catalog/pg_am_d.h"
#include "catalog/pg_index.h"
#include "lib/stringinfo.h"
#include "storage/bufmgr.h"
#include "storage/shm_toc.h"
/* There's room for a 16-bit vacuum cycle ID in BTPageOpaqueData */
typedef uint16 BTCycleId;
/*
* BTPageOpaqueData -- At the end of every page, we store a pointer
* to both siblings in the tree. This is used to do forward/backward
* index scans. The next-page link is also critical for recovery when
* a search has navigated to the wrong page due to concurrent page splits
* or deletions; see src/backend/access/nbtree/README for more info.
*
* In addition, we store the page's btree level (counting upwards from
* zero at a leaf page) as well as some flag bits indicating the page type
* and status. If the page is deleted, a BTDeletedPageData struct is stored
* in the page's tuple area, while a standard BTPageOpaqueData struct is
* stored in the page special area.
*
* We also store a "vacuum cycle ID". When a page is split while VACUUM is
* processing the index, a nonzero value associated with the VACUUM run is
* stored into both halves of the split page. (If VACUUM is not running,
* both pages receive zero cycleids.) This allows VACUUM to detect whether
* a page was split since it started, with a small probability of false match
* if the page was last split some exact multiple of MAX_BT_CYCLE_ID VACUUMs
* ago. Also, during a split, the BTP_SPLIT_END flag is cleared in the left
* (original) page, and set in the right page, but only if the next page
* to its right has a different cycleid.
*
* NOTE: the BTP_LEAF flag bit is redundant since level==0 could be tested
* instead.
*
* NOTE: the btpo_level field used to be a union type in order to allow
* deleted pages to store a 32-bit safexid in the same field. We now store
* 64-bit/full safexid values using BTDeletedPageData instead.
*/
typedef struct BTPageOpaqueData
{
BlockNumber btpo_prev; /* left sibling, or P_NONE if leftmost */
BlockNumber btpo_next; /* right sibling, or P_NONE if rightmost */
uint32 btpo_level; /* tree level --- zero for leaf pages */
uint16 btpo_flags; /* flag bits, see below */
BTCycleId btpo_cycleid; /* vacuum cycle ID of latest split */
} BTPageOpaqueData;
typedef BTPageOpaqueData *BTPageOpaque;
#define BTPageGetOpaque(page) ((BTPageOpaque) PageGetSpecialPointer(page))
/* Bits defined in btpo_flags */
#define BTP_LEAF (1 << 0) /* leaf page, i.e. not internal page */
#define BTP_ROOT (1 << 1) /* root page (has no parent) */
#define BTP_DELETED (1 << 2) /* page has been deleted from tree */
#define BTP_META (1 << 3) /* meta-page */
#define BTP_HALF_DEAD (1 << 4) /* empty, but still in tree */
#define BTP_SPLIT_END (1 << 5) /* rightmost page of split group */
#define BTP_HAS_GARBAGE (1 << 6) /* page has LP_DEAD tuples (deprecated) */
#define BTP_INCOMPLETE_SPLIT (1 << 7) /* right sibling's downlink is missing */
#define BTP_HAS_FULLXID (1 << 8) /* contains BTDeletedPageData */
/*
* The max allowed value of a cycle ID is a bit less than 64K. This is
* for convenience of pg_filedump and similar utilities: we want to use
* the last 2 bytes of special space as an index type indicator, and
* restricting cycle ID lets btree use that space for vacuum cycle IDs
* while still allowing index type to be identified.
*/
#define MAX_BT_CYCLE_ID 0xFF7F
/*
* 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.
* We also point to the "fast" root, which is the current effective root;
* see README for discussion.
*/
typedef struct BTMetaPageData
{
uint32 btm_magic; /* should contain BTREE_MAGIC */
uint32 btm_version; /* nbtree version (always <= BTREE_VERSION) */
BlockNumber btm_root; /* current root location */
uint32 btm_level; /* tree level of the root page */
BlockNumber btm_fastroot; /* current "fast" root location */
uint32 btm_fastlevel; /* tree level of the "fast" root page */
/* remaining fields only valid when btm_version >= BTREE_NOVAC_VERSION */
/* number of deleted, non-recyclable pages during last cleanup */
uint32 btm_last_cleanup_num_delpages;
/* number of heap tuples during last cleanup (deprecated) */
float8 btm_last_cleanup_num_heap_tuples;
bool btm_allequalimage; /* are all columns "equalimage"? */
} BTMetaPageData;
#define BTPageGetMeta(p) \
((BTMetaPageData *) PageGetContents(p))
/*
* The current Btree version is 4. That's what you'll get when you create
* a new index.
*
* Btree version 3 was used in PostgreSQL v11. It is mostly the same as
* version 4, but heap TIDs were not part of the keyspace. Index tuples
* with duplicate keys could be stored in any order. We continue to
* support reading and writing Btree versions 2 and 3, so that they don't
* need to be immediately re-indexed at pg_upgrade. In order to get the
* new heapkeyspace semantics, however, a REINDEX is needed.
*
* Deduplication is safe to use when the btm_allequalimage field is set to
* true. It's safe to read the btm_allequalimage field on version 3, but
* only version 4 indexes make use of deduplication. Even version 4
* indexes created on PostgreSQL v12 will need a REINDEX to make use of
* deduplication, though, since there is no other way to set
* btm_allequalimage to true (pg_upgrade hasn't been taught to set the
* metapage field).
*
* Btree version 2 is mostly the same as version 3. There are two new
* fields in the metapage that were introduced in version 3. A version 2
* metapage will be automatically upgraded to version 3 on the first
* insert to it. INCLUDE indexes cannot use version 2.
*/
#define BTREE_METAPAGE 0 /* first page is meta */
#define BTREE_MAGIC 0x053162 /* magic number in metapage */
#define BTREE_VERSION 4 /* current version number */
#define BTREE_MIN_VERSION 2 /* minimum supported version */
#define BTREE_NOVAC_VERSION 3 /* version with all meta fields set */
/*
* Maximum size of a btree index entry, including its tuple header.
*
* We actually need to be able to fit three items on every page,
* so restrict any one item to 1/3 the per-page available space.
*
* There are rare cases where _bt_truncate() will need to enlarge
* a heap index tuple to make space for a tiebreaker heap TID
* attribute, which we account for here.
*/
#define BTMaxItemSize(page) \
(MAXALIGN_DOWN((PageGetPageSize(page) - \
MAXALIGN(SizeOfPageHeaderData + 3*sizeof(ItemIdData)) - \
MAXALIGN(sizeof(BTPageOpaqueData))) / 3) - \
MAXALIGN(sizeof(ItemPointerData)))
#define BTMaxItemSizeNoHeapTid(page) \
MAXALIGN_DOWN((PageGetPageSize(page) - \
MAXALIGN(SizeOfPageHeaderData + 3*sizeof(ItemIdData)) - \
MAXALIGN(sizeof(BTPageOpaqueData))) / 3)
/*
* MaxTIDsPerBTreePage is an upper bound on the number of heap TIDs tuples
* that may be stored on a btree leaf page. It is used to size the
* per-page temporary buffers.
*
* Note: we don't bother considering per-tuple overheads here to keep
* things simple (value is based on how many elements a single array of
* heap TIDs must have to fill the space between the page header and
* special area). The value is slightly higher (i.e. more conservative)
* than necessary as a result, which is considered acceptable.
*/
#define MaxTIDsPerBTreePage \
(int) ((BLCKSZ - SizeOfPageHeaderData - sizeof(BTPageOpaqueData)) / \
sizeof(ItemPointerData))
/*
* The leaf-page fillfactor defaults to 90% but is user-adjustable.
* For pages above the leaf level, we use a fixed 70% fillfactor.
* The fillfactor is applied during index build and when splitting
* a rightmost page; when splitting non-rightmost pages we try to
* divide the data equally. When splitting a page that's entirely
* filled with a single value (duplicates), the effective leaf-page
* fillfactor is 96%, regardless of whether the page is a rightmost
* page.
*/
#define BTREE_MIN_FILLFACTOR 10
#define BTREE_DEFAULT_FILLFACTOR 90
#define BTREE_NONLEAF_FILLFACTOR 70
#define BTREE_SINGLEVAL_FILLFACTOR 96
/*
* In general, the btree code tries to localize its knowledge about
* page layout to a couple of routines. However, we need a special
* value to indicate "no page number" in those places where we expect
* page numbers. We can use zero for this because we never need to
* make a pointer to the metadata page.
*/
#define P_NONE 0
/*
* Macros to test whether a page is leftmost or rightmost on its tree level,
* as well as other state info kept in the opaque data.
*/
#define P_LEFTMOST(opaque) ((opaque)->btpo_prev == P_NONE)
#define P_RIGHTMOST(opaque) ((opaque)->btpo_next == P_NONE)
#define P_ISLEAF(opaque) (((opaque)->btpo_flags & BTP_LEAF) != 0)
#define P_ISROOT(opaque) (((opaque)->btpo_flags & BTP_ROOT) != 0)
#define P_ISDELETED(opaque) (((opaque)->btpo_flags & BTP_DELETED) != 0)
#define P_ISMETA(opaque) (((opaque)->btpo_flags & BTP_META) != 0)
#define P_ISHALFDEAD(opaque) (((opaque)->btpo_flags & BTP_HALF_DEAD) != 0)
#define P_IGNORE(opaque) (((opaque)->btpo_flags & (BTP_DELETED|BTP_HALF_DEAD)) != 0)
#define P_HAS_GARBAGE(opaque) (((opaque)->btpo_flags & BTP_HAS_GARBAGE) != 0)
#define P_INCOMPLETE_SPLIT(opaque) (((opaque)->btpo_flags & BTP_INCOMPLETE_SPLIT) != 0)
#define P_HAS_FULLXID(opaque) (((opaque)->btpo_flags & BTP_HAS_FULLXID) != 0)
/*
* BTDeletedPageData is the page contents of a deleted page
*/
typedef struct BTDeletedPageData
{
FullTransactionId safexid; /* See BTPageIsRecyclable() */
} BTDeletedPageData;
static inline void
BTPageSetDeleted(Page page, FullTransactionId safexid)
{
BTPageOpaque opaque;
PageHeader header;
BTDeletedPageData *contents;
opaque = BTPageGetOpaque(page);
header = ((PageHeader) page);
opaque->btpo_flags &= ~BTP_HALF_DEAD;
opaque->btpo_flags |= BTP_DELETED | BTP_HAS_FULLXID;
header->pd_lower = MAXALIGN(SizeOfPageHeaderData) +
sizeof(BTDeletedPageData);
header->pd_upper = header->pd_special;
/* Set safexid in deleted page */
contents = ((BTDeletedPageData *) PageGetContents(page));
contents->safexid = safexid;
}
static inline FullTransactionId
BTPageGetDeleteXid(Page page)
{
BTPageOpaque opaque;
BTDeletedPageData *contents;
/* We only expect to be called with a deleted page */
Assert(!PageIsNew(page));
opaque = BTPageGetOpaque(page);
Assert(P_ISDELETED(opaque));
/* pg_upgrade'd deleted page -- must be safe to delete now */
if (!P_HAS_FULLXID(opaque))
return FirstNormalFullTransactionId;
/* Get safexid from deleted page */
contents = ((BTDeletedPageData *) PageGetContents(page));
return contents->safexid;
}
/*
* Is an existing page recyclable?
*
* This exists to centralize the policy on which deleted pages are now safe to
* re-use. However, _bt_pendingfsm_finalize() duplicates some of the same
* logic because it doesn't work directly with pages -- keep the two in sync.
*
* Note: PageIsNew() pages are always safe to recycle, but we can't deal with
* them here (caller is responsible for that case themselves). Caller might
* well need special handling for new pages anyway.
*/
static inline bool
BTPageIsRecyclable(Page page, Relation heaprel)
{
BTPageOpaque opaque;
Assert(!PageIsNew(page));
Assert(heaprel != NULL);
/* Recycling okay iff page is deleted and safexid is old enough */
opaque = BTPageGetOpaque(page);
if (P_ISDELETED(opaque))
{
FullTransactionId safexid = BTPageGetDeleteXid(page);
/*
* The page was deleted, but when? If it was just deleted, a scan
* might have seen the downlink to it, and will read the page later.
* As long as that can happen, we must keep the deleted page around as
* a tombstone.
*
* For that check if the deletion XID could still be visible to
* anyone. If not, then no scan that's still in progress could have
* seen its downlink, and we can recycle it.
*/
return GlobalVisCheckRemovableFullXid(heaprel, safexid);
}
return false;
}
/*
* BTVacState and BTPendingFSM are private nbtree.c state used during VACUUM.
* They are exported for use by page deletion related code in nbtpage.c.
*/
typedef struct BTPendingFSM
{
BlockNumber target; /* Page deleted by current VACUUM */
FullTransactionId safexid; /* Page's BTDeletedPageData.safexid */
} BTPendingFSM;
typedef struct BTVacState
{
IndexVacuumInfo *info;
IndexBulkDeleteResult *stats;
IndexBulkDeleteCallback callback;
void *callback_state;
BTCycleId cycleid;
MemoryContext pagedelcontext;
/*
* _bt_pendingfsm_finalize() state
*/
int bufsize; /* pendingpages space (in # elements) */
int maxbufsize; /* max bufsize that respects work_mem */
BTPendingFSM *pendingpages; /* One entry per newly deleted page */
int npendingpages; /* current # valid pendingpages */
} BTVacState;
/*
* Lehman and Yao's algorithm requires a ``high key'' on every non-rightmost
* page. The high key is not a tuple that is used to visit the heap. It is
* a pivot tuple (see "Notes on B-Tree tuple format" below for definition).
* The high key on a page is required to be greater than or equal to any
* other key that appears on the page. If we find ourselves trying to
* insert a key that is strictly > high key, we know we need to move right
* (this should only happen if the page was split since we examined the
* parent page).
*
* Our insertion algorithm guarantees that we can use the initial least key
* on our right sibling as the high key. Once a page is created, its high
* key changes only if the page is split.
*
* On a non-rightmost page, the high key lives in item 1 and data items
* start in item 2. Rightmost pages have no high key, so we store data
* items beginning in item 1.
*/
#define P_HIKEY ((OffsetNumber) 1)
#define P_FIRSTKEY ((OffsetNumber) 2)
#define P_FIRSTDATAKEY(opaque) (P_RIGHTMOST(opaque) ? P_HIKEY : P_FIRSTKEY)
/*
* Notes on B-Tree tuple format, and key and non-key attributes:
*
* INCLUDE B-Tree indexes have non-key attributes. These are extra
* attributes that may be returned by index-only scans, but do not influence
* the order of items in the index (formally, non-key attributes are not
* considered to be part of the key space). Non-key attributes are only
* present in leaf index tuples whose item pointers actually point to heap
* tuples (non-pivot tuples). _bt_check_natts() enforces the rules
* described here.
*
* Non-pivot tuple format (plain/non-posting variant):
*
* t_tid | t_info | key values | INCLUDE columns, if any
*
* t_tid points to the heap TID, which is a tiebreaker key column as of
* BTREE_VERSION 4.
*
* Non-pivot tuples complement pivot tuples, which only have key columns.
* The sole purpose of pivot tuples is to represent how the key space is
* separated. In general, any B-Tree index that has more than one level
* (i.e. any index that does not just consist of a metapage and a single
* leaf root page) must have some number of pivot tuples, since pivot
* tuples are used for traversing the tree. Suffix truncation can omit
* trailing key columns when a new pivot is formed, which makes minus
* infinity their logical value. Since BTREE_VERSION 4 indexes treat heap
* TID as a trailing key column that ensures that all index tuples are
* physically unique, it is necessary to represent heap TID as a trailing
* key column in pivot tuples, though very often this can be truncated
* away, just like any other key column. (Actually, the heap TID is
* omitted rather than truncated, since its representation is different to
* the non-pivot representation.)
*
* Pivot tuple format:
*
* t_tid | t_info | key values | [heap TID]
*
* We store the number of columns present inside pivot tuples by abusing
* their t_tid offset field, since pivot tuples never need to store a real
* offset (pivot tuples generally store a downlink in t_tid, though). The
* offset field only stores the number of columns/attributes when the
* INDEX_ALT_TID_MASK bit is set, which doesn't count the trailing heap
* TID column sometimes stored in pivot tuples -- that's represented by
* the presence of BT_PIVOT_HEAP_TID_ATTR. The INDEX_ALT_TID_MASK bit in
* t_info is always set on BTREE_VERSION 4 pivot tuples, since
* BTreeTupleIsPivot() must work reliably on heapkeyspace versions.
*
* In version 2 or version 3 (!heapkeyspace) indexes, INDEX_ALT_TID_MASK
* might not be set in pivot tuples. BTreeTupleIsPivot() won't work
* reliably as a result. The number of columns stored is implicitly the
* same as the number of columns in the index, just like any non-pivot
* tuple. (The number of columns stored should not vary, since suffix
* truncation of key columns is unsafe within any !heapkeyspace index.)
*
* The 12 least significant bits from t_tid's offset number are used to
* represent the number of key columns within a pivot tuple. This leaves 4
* status bits (BT_STATUS_OFFSET_MASK bits), which are shared by all tuples
* that have the INDEX_ALT_TID_MASK bit set (set in t_info) to store basic
* tuple metadata. BTreeTupleIsPivot() and BTreeTupleIsPosting() use the
* BT_STATUS_OFFSET_MASK bits.
*
* Sometimes non-pivot tuples also use a representation that repurposes
* t_tid to store metadata rather than a TID. PostgreSQL v13 introduced a
* new non-pivot tuple format to support deduplication: posting list
* tuples. Deduplication merges together multiple equal non-pivot tuples
* into a logically equivalent, space efficient representation. A posting
* list is an array of ItemPointerData elements. Non-pivot tuples are
* merged together to form posting list tuples lazily, at the point where
* we'd otherwise have to split a leaf page.
*
* Posting tuple format (alternative non-pivot tuple representation):
*
* t_tid | t_info | key values | posting list (TID array)
*
* Posting list tuples are recognized as such by having the
* INDEX_ALT_TID_MASK status bit set in t_info and the BT_IS_POSTING status
* bit set in t_tid's offset number. These flags redefine the content of
* the posting tuple's t_tid to store the location of the posting list
* (instead of a block number), as well as the total number of heap TIDs
* present in the tuple (instead of a real offset number).
*
* The 12 least significant bits from t_tid's offset number are used to
* represent the number of heap TIDs present in the tuple, leaving 4 status
* bits (the BT_STATUS_OFFSET_MASK bits). Like any non-pivot tuple, the
* number of columns stored is always implicitly the total number in the
* index (in practice there can never be non-key columns stored, since
* deduplication is not supported with INCLUDE indexes).
*/
#define INDEX_ALT_TID_MASK INDEX_AM_RESERVED_BIT
/* Item pointer offset bit masks */
#define BT_OFFSET_MASK 0x0FFF
#define BT_STATUS_OFFSET_MASK 0xF000
/* BT_STATUS_OFFSET_MASK status bits */
#define BT_PIVOT_HEAP_TID_ATTR 0x1000
#define BT_IS_POSTING 0x2000
/*
* Mask allocated for number of keys in index tuple must be able to fit
* maximum possible number of index attributes
*/
StaticAssertDecl(BT_OFFSET_MASK >= INDEX_MAX_KEYS,
"BT_OFFSET_MASK can't fit INDEX_MAX_KEYS");
/*
* Note: BTreeTupleIsPivot() can have false negatives (but not false
* positives) when used with !heapkeyspace indexes
*/
static inline bool
BTreeTupleIsPivot(IndexTuple itup)
{
if ((itup->t_info & INDEX_ALT_TID_MASK) == 0)
return false;
/* absence of BT_IS_POSTING in offset number indicates pivot tuple */
if ((ItemPointerGetOffsetNumberNoCheck(&itup->t_tid) & BT_IS_POSTING) != 0)
return false;
return true;
}
static inline bool
BTreeTupleIsPosting(IndexTuple itup)
{
if ((itup->t_info & INDEX_ALT_TID_MASK) == 0)
return false;
/* presence of BT_IS_POSTING in offset number indicates posting tuple */
if ((ItemPointerGetOffsetNumberNoCheck(&itup->t_tid) & BT_IS_POSTING) == 0)
return false;
return true;
}
static inline void
BTreeTupleSetPosting(IndexTuple itup, uint16 nhtids, int postingoffset)
{
Assert(nhtids > 1);
Assert((nhtids & BT_STATUS_OFFSET_MASK) == 0);
Assert((size_t) postingoffset == MAXALIGN(postingoffset));
Assert(postingoffset < INDEX_SIZE_MASK);
Assert(!BTreeTupleIsPivot(itup));
itup->t_info |= INDEX_ALT_TID_MASK;
ItemPointerSetOffsetNumber(&itup->t_tid, (nhtids | BT_IS_POSTING));
ItemPointerSetBlockNumber(&itup->t_tid, postingoffset);
}
static inline uint16
BTreeTupleGetNPosting(IndexTuple posting)
{
OffsetNumber existing;
Assert(BTreeTupleIsPosting(posting));
existing = ItemPointerGetOffsetNumberNoCheck(&posting->t_tid);
return (existing & BT_OFFSET_MASK);
}
static inline uint32
BTreeTupleGetPostingOffset(IndexTuple posting)
{
Assert(BTreeTupleIsPosting(posting));
return ItemPointerGetBlockNumberNoCheck(&posting->t_tid);
}
static inline ItemPointer
BTreeTupleGetPosting(IndexTuple posting)
{
return (ItemPointer) ((char *) posting +
BTreeTupleGetPostingOffset(posting));
}
static inline ItemPointer
BTreeTupleGetPostingN(IndexTuple posting, int n)
{
return BTreeTupleGetPosting(posting) + n;
}
/*
* Get/set downlink block number in pivot tuple.
*
* Note: Cannot assert that tuple is a pivot tuple. If we did so then
* !heapkeyspace indexes would exhibit false positive assertion failures.
*/
static inline BlockNumber
BTreeTupleGetDownLink(IndexTuple pivot)
{
return ItemPointerGetBlockNumberNoCheck(&pivot->t_tid);
}
static inline void
BTreeTupleSetDownLink(IndexTuple pivot, BlockNumber blkno)
{
ItemPointerSetBlockNumber(&pivot->t_tid, blkno);
}
/*
* Get number of attributes within tuple.
*
* Note that this does not include an implicit tiebreaker heap TID
* attribute, if any. Note also that the number of key attributes must be
* explicitly represented in all heapkeyspace pivot tuples.
*
* Note: This is defined as a macro rather than an inline function to
* avoid including rel.h.
*/
#define BTreeTupleGetNAtts(itup, rel) \
( \
(BTreeTupleIsPivot(itup)) ? \
( \
ItemPointerGetOffsetNumberNoCheck(&(itup)->t_tid) & BT_OFFSET_MASK \
) \
: \
IndexRelationGetNumberOfAttributes(rel) \
)
/*
* Set number of key attributes in tuple.
*
* The heap TID tiebreaker attribute bit may also be set here, indicating that
* a heap TID value will be stored at the end of the tuple (i.e. using the
* special pivot tuple representation).
*/
static inline void
BTreeTupleSetNAtts(IndexTuple itup, uint16 nkeyatts, bool heaptid)
{
Assert(nkeyatts <= INDEX_MAX_KEYS);
Assert((nkeyatts & BT_STATUS_OFFSET_MASK) == 0);
Assert(!heaptid || nkeyatts > 0);
Assert(!BTreeTupleIsPivot(itup) || nkeyatts == 0);
itup->t_info |= INDEX_ALT_TID_MASK;
if (heaptid)
nkeyatts |= BT_PIVOT_HEAP_TID_ATTR;
/* BT_IS_POSTING bit is deliberately unset here */
ItemPointerSetOffsetNumber(&itup->t_tid, nkeyatts);
Assert(BTreeTupleIsPivot(itup));
}
/*
* Get/set leaf page's "top parent" link from its high key. Used during page
* deletion.
*
* Note: Cannot assert that tuple is a pivot tuple. If we did so then
* !heapkeyspace indexes would exhibit false positive assertion failures.
*/
static inline BlockNumber
BTreeTupleGetTopParent(IndexTuple leafhikey)
{
return ItemPointerGetBlockNumberNoCheck(&leafhikey->t_tid);
}
static inline void
BTreeTupleSetTopParent(IndexTuple leafhikey, BlockNumber blkno)
{
ItemPointerSetBlockNumber(&leafhikey->t_tid, blkno);
BTreeTupleSetNAtts(leafhikey, 0, false);
}
/*
* Get tiebreaker heap TID attribute, if any.
*
* This returns the first/lowest heap TID in the case of a posting list tuple.
*/
static inline ItemPointer
BTreeTupleGetHeapTID(IndexTuple itup)
{
if (BTreeTupleIsPivot(itup))
{
/* Pivot tuple heap TID representation? */
if ((ItemPointerGetOffsetNumberNoCheck(&itup->t_tid) &
BT_PIVOT_HEAP_TID_ATTR) != 0)
return (ItemPointer) ((char *) itup + IndexTupleSize(itup) -
sizeof(ItemPointerData));
/* Heap TID attribute was truncated */
return NULL;
}
else if (BTreeTupleIsPosting(itup))
return BTreeTupleGetPosting(itup);
return &itup->t_tid;
}
/*
* Get maximum heap TID attribute, which could be the only TID in the case of
* a non-pivot tuple that does not have a posting list tuple.
*
* Works with non-pivot tuples only.
*/
static inline ItemPointer
BTreeTupleGetMaxHeapTID(IndexTuple itup)
{
Assert(!BTreeTupleIsPivot(itup));
if (BTreeTupleIsPosting(itup))
{
uint16 nposting = BTreeTupleGetNPosting(itup);
return BTreeTupleGetPostingN(itup, nposting - 1);
}
return &itup->t_tid;
}
/*
* Operator strategy numbers for B-tree have been moved to access/stratnum.h,
* because many places need to use them in ScanKeyInit() calls.
*
* The strategy numbers are chosen so that we can commute them by
* subtraction, thus:
*/
#define BTCommuteStrategyNumber(strat) (BTMaxStrategyNumber + 1 - (strat))
/*
* When a new operator class is declared, we require that the user
* supply us with an amproc procedure (BTORDER_PROC) for determining
* whether, for two keys a and b, a < b, a = b, or a > b. This routine
* must return < 0, 0, > 0, respectively, in these three cases.
*
* To facilitate accelerated sorting, an operator class may choose to
* offer a second procedure (BTSORTSUPPORT_PROC). For full details, see
* src/include/utils/sortsupport.h.
*
* To support window frames defined by "RANGE offset PRECEDING/FOLLOWING",
* an operator class may choose to offer a third amproc procedure
* (BTINRANGE_PROC), independently of whether it offers sortsupport.
* For full details, see doc/src/sgml/btree.sgml.
*
* To facilitate B-Tree deduplication, an operator class may choose to
* offer a forth amproc procedure (BTEQUALIMAGE_PROC). For full details,
* see doc/src/sgml/btree.sgml.
*/
#define BTORDER_PROC 1
#define BTSORTSUPPORT_PROC 2
#define BTINRANGE_PROC 3
#define BTEQUALIMAGE_PROC 4
#define BTOPTIONS_PROC 5
#define BTNProcs 5
/*
* We need to be able to tell the difference between read and write
* requests for pages, in order to do locking correctly.
*/
#define BT_READ BUFFER_LOCK_SHARE
#define BT_WRITE BUFFER_LOCK_EXCLUSIVE
/*
* 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 also have to
* recursively insert into the grandparent page if and when the parent page
* splits. Our private stack can become stale due to concurrent page
* splits and page deletions, but it should never give us an irredeemably
* bad picture.
*/
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.
*
* allequalimage is set to indicate that deduplication is safe for the index.
* This is also a property of the index relation rather than an indexscan.
*
* 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 allequalimage;
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;
/*
* if _bt_binsrch_insert found the location inside existing posting list,
* save the position inside the list. -1 sentinel value indicates overlap
* with an existing posting list tuple that has its LP_DEAD bit set.
*/
int postingoff;
} BTInsertStateData;
typedef BTInsertStateData *BTInsertState;
/*
* State used to representing an individual pending tuple during
* deduplication.
*/
typedef struct BTDedupInterval
{
OffsetNumber baseoff;
uint16 nitems;
} BTDedupInterval;
/*
* BTDedupStateData is a working area used during deduplication.
*
* The status info fields track the state of a whole-page deduplication pass.
* State about the current pending posting list is also tracked.
*
* A pending posting list is comprised of a contiguous group of equal items
* from the page, starting from page offset number 'baseoff'. This is the
* offset number of the "base" tuple for new posting list. 'nitems' is the
* current total number of existing items from the page that will be merged to
* make a new posting list tuple, including the base tuple item. (Existing
* items may themselves be posting list tuples, or regular non-pivot tuples.)
*
* The total size of the existing tuples to be freed when pending posting list
* is processed gets tracked by 'phystupsize'. This information allows
* deduplication to calculate the space saving for each new posting list
* tuple, and for the entire pass over the page as a whole.
*/
typedef struct BTDedupStateData
{
/* Deduplication status info for entire pass over page */
bool deduplicate; /* Still deduplicating page? */
int nmaxitems; /* Number of max-sized tuples so far */
Size maxpostingsize; /* Limit on size of final tuple */
/* Metadata about base tuple of current pending posting list */
IndexTuple base; /* Use to form new posting list */
OffsetNumber baseoff; /* page offset of base */
Size basetupsize; /* base size without original posting list */
/* Other metadata about pending posting list */
ItemPointer htids; /* Heap TIDs in pending posting list */
int nhtids; /* Number of heap TIDs in htids array */
int nitems; /* Number of existing tuples/line pointers */
Size phystupsize; /* Includes line pointer overhead */
/*
* Array of tuples to go on new version of the page. Contains one entry
* for each group of consecutive items. Note that existing tuples that
* will not become posting list tuples do not appear in the array (they
* are implicitly unchanged by deduplication pass).
*/
int nintervals; /* current number of intervals in array */
BTDedupInterval intervals[MaxIndexTuplesPerPage];
} BTDedupStateData;
typedef BTDedupStateData *BTDedupState;
/*
* BTVacuumPostingData is state that represents how to VACUUM (or delete) a
* posting list tuple when some (though not all) of its TIDs are to be
* deleted.
*
* Convention is that itup field is the original posting list tuple on input,
* and palloc()'d final tuple used to overwrite existing tuple on output.
*/
typedef struct BTVacuumPostingData
{
/* Tuple that will be/was updated */
IndexTuple itup;
OffsetNumber updatedoffset;
/* State needed to describe final itup in WAL */
uint16 ndeletedtids;
uint16 deletetids[FLEXIBLE_ARRAY_MEMBER];
} BTVacuumPostingData;
typedef BTVacuumPostingData *BTVacuumPosting;
/*
* 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. Posting list tuples store a "base" tuple once,
* allowing the same key to be returned for each TID in the posting list
* tuple.
*/
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[MaxTIDsPerBTreePage]; /* 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
{
/* all fields (except arraysStarted) are set by _bt_preprocess_keys(): */
bool qual_ok; /* false if qual can never be satisfied */
bool arraysStarted; /* Started array keys, but have yet to "reach
* past the end" of all arrays? */
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)
typedef struct BTOptions
{
int32 varlena_header_; /* varlena header (do not touch directly!) */
int fillfactor; /* page fill factor in percent (0..100) */
float8 vacuum_cleanup_index_scale_factor; /* deprecated */
bool deduplicate_items; /* Try to deduplicate items? */
} BTOptions;
#define BTGetFillFactor(relation) \
(AssertMacro(relation->rd_rel->relkind == RELKIND_INDEX && \
relation->rd_rel->relam == BTREE_AM_OID), \
(relation)->rd_options ? \
((BTOptions *) (relation)->rd_options)->fillfactor : \
BTREE_DEFAULT_FILLFACTOR)
#define BTGetTargetPageFreeSpace(relation) \
(BLCKSZ * (100 - BTGetFillFactor(relation)) / 100)
#define BTGetDeduplicateItems(relation) \
(AssertMacro(relation->rd_rel->relkind == RELKIND_INDEX && \
relation->rd_rel->relam == BTREE_AM_OID), \
((relation)->rd_options ? \
((BTOptions *) (relation)->rd_options)->deduplicate_items : true))
/*
* 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,
bool indexUnchanged,
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 nbtdedup.c
*/
extern void _bt_dedup_pass(Relation rel, Buffer buf, IndexTuple newitem,
Size newitemsz, bool bottomupdedup);
extern bool _bt_bottomupdel_pass(Relation rel, Buffer buf, Relation heapRel,
Size newitemsz);
extern void _bt_dedup_start_pending(BTDedupState state, IndexTuple base,
OffsetNumber baseoff);
extern bool _bt_dedup_save_htid(BTDedupState state, IndexTuple itup);
extern Size _bt_dedup_finish_pending(Page newpage, BTDedupState state);
extern IndexTuple _bt_form_posting(IndexTuple base, ItemPointer htids,
int nhtids);
extern void _bt_update_posting(BTVacuumPosting vacposting);
extern IndexTuple _bt_swap_posting(IndexTuple newitem, IndexTuple oposting,
int postingoff);
/*
* prototypes for functions in nbtinsert.c
*/
extern bool _bt_doinsert(Relation rel, IndexTuple itup,
IndexUniqueCheck checkUnique, bool indexUnchanged,
Relation heapRel);
extern void _bt_finish_split(Relation rel, Relation heaprel, Buffer lbuf,
BTStack stack);
extern Buffer _bt_getstackbuf(Relation rel, Relation heaprel, BTStack stack,
BlockNumber child);
/*
* prototypes for functions in nbtsplitloc.c
*/
extern OffsetNumber _bt_findsplitloc(Relation rel, Page origpage,
OffsetNumber newitemoff, Size newitemsz, IndexTuple newitem,
bool *newitemonleft);
/*
* prototypes for functions in nbtpage.c
*/
extern void _bt_initmetapage(Page page, BlockNumber rootbknum, uint32 level,
bool allequalimage);
extern bool _bt_vacuum_needs_cleanup(Relation rel);
extern void _bt_set_cleanup_info(Relation rel, BlockNumber num_delpages);
extern void _bt_upgrademetapage(Page page);
extern Buffer _bt_getroot(Relation rel, Relation heaprel, int access);
extern Buffer _bt_gettrueroot(Relation rel);
extern int _bt_getrootheight(Relation rel);
extern void _bt_metaversion(Relation rel, bool *heapkeyspace,
bool *allequalimage);
extern void _bt_checkpage(Relation rel, Buffer buf);
extern Buffer _bt_getbuf(Relation rel, BlockNumber blkno, int access);
extern Buffer _bt_allocbuf(Relation rel, Relation heaprel);
extern Buffer _bt_relandgetbuf(Relation rel, Buffer obuf,
BlockNumber blkno, int access);
extern void _bt_relbuf(Relation rel, Buffer buf);
extern void _bt_lockbuf(Relation rel, Buffer buf, int access);
extern void _bt_unlockbuf(Relation rel, Buffer buf);
extern bool _bt_conditionallockbuf(Relation rel, Buffer buf);
extern void _bt_upgradelockbufcleanup(Relation rel, Buffer buf);
extern void _bt_pageinit(Page page, Size size);
extern void _bt_delitems_vacuum(Relation rel, Buffer buf,
OffsetNumber *deletable, int ndeletable,
BTVacuumPosting *updatable, int nupdatable);
extern void _bt_delitems_delete_check(Relation rel, Buffer buf,
Relation heapRel,
TM_IndexDeleteOp *delstate);
extern void _bt_pagedel(Relation rel, Buffer leafbuf, BTVacState *vstate);
extern void _bt_pendingfsm_init(Relation rel, BTVacState *vstate,
bool cleanuponly);
extern void _bt_pendingfsm_finalize(Relation rel, BTVacState *vstate);
/*
* prototypes for functions in nbtsearch.c
*/
extern BTStack _bt_search(Relation rel, Relation heaprel, BTScanInsert key,
Buffer *bufP, int access, Snapshot snapshot);
extern Buffer _bt_moveright(Relation rel, Relation heaprel, 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);
extern bool _bt_allequalimage(Relation rel, bool debugmessage);
/*
* prototypes for functions in nbtvalidate.c
*/
extern bool btvalidate(Oid opclassoid);
extern void btadjustmembers(Oid opfamilyoid,
Oid opclassoid,
List *operators,
List *functions);
/*
* 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 */