Viewing file:  nbtree.h (30.12 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/*-------------------------------------------------------------------------
*
* nbtree.h
* header file for postgres btree access method implementation.
*
*
* Portions Copyright (c) 1996-2016, 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/xlogreader.h"
#include "catalog/pg_index.h"
#include "lib/stringinfo.h"
#include "storage/bufmgr.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, we replace the level with the
* next-transaction-ID value indicating when it is safe to reclaim the page.
*
* 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.
*/
typedef struct BTPageOpaqueData
{
BlockNumber btpo_prev; /* left sibling, or P_NONE if leftmost */
BlockNumber btpo_next; /* right sibling, or P_NONE if rightmost */
union
{
uint32 level; /* tree level --- zero for leaf pages */
TransactionId xact; /* next transaction ID, if deleted */
} btpo;
uint16 btpo_flags; /* flag bits, see below */
BTCycleId btpo_cycleid; /* vacuum cycle ID of latest split */
} BTPageOpaqueData;
typedef BTPageOpaqueData *BTPageOpaque;
/* 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 */
#define BTP_INCOMPLETE_SPLIT (1 << 7) /* right sibling's downlink is missing */
/*
* 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; /* should contain 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 */
} BTMetaPageData;
#define BTPageGetMeta(p) \
((BTMetaPageData *) PageGetContents(p))
#define BTREE_METAPAGE 0 /* first page is meta */
#define BTREE_MAGIC 0x053162 /* magic number of btree pages */
#define BTREE_VERSION 2 /* current version number */
/*
* 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.
*/
#define BTMaxItemSize(page) \
MAXALIGN_DOWN((PageGetPageSize(page) - \
MAXALIGN(SizeOfPageHeaderData + 3*sizeof(ItemIdData)) - \
MAXALIGN(sizeof(BTPageOpaqueData))) / 3)
/*
* 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.
*/
#define BTREE_MIN_FILLFACTOR 10
#define BTREE_DEFAULT_FILLFACTOR 90
#define BTREE_NONLEAF_FILLFACTOR 70
/*
* Test whether two btree entries are "the same".
*
* Old comments:
* In addition, we must guarantee that all tuples in the index are unique,
* in order to satisfy some assumptions in Lehman and Yao. The way that we
* do this is by generating a new OID for every insertion that we do in the
* tree. This adds eight bytes to the size of btree index tuples. Note
* that we do not use the OID as part of a composite key; the OID only
* serves as a unique identifier for a given index tuple (logical position
* within a page).
*
* New comments:
* actually, we must guarantee that all tuples in A LEVEL
* are unique, not in ALL INDEX. So, we can use the t_tid
* as unique identifier for a given index tuple (logical position
* within a level). - vadim 04/09/97
*/
#define BTTidSame(i1, i2) \
( (i1).ip_blkid.bi_hi == (i2).ip_blkid.bi_hi && \
(i1).ip_blkid.bi_lo == (i2).ip_blkid.bi_lo && \
(i1).ip_posid == (i2).ip_posid )
#define BTEntrySame(i1, i2) \
BTTidSame((i1)->t_tid, (i2)->t_tid)
/*
* 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)
#define P_ISROOT(opaque) ((opaque)->btpo_flags & BTP_ROOT)
#define P_ISDELETED(opaque) ((opaque)->btpo_flags & BTP_DELETED)
#define P_ISHALFDEAD(opaque) ((opaque)->btpo_flags & BTP_HALF_DEAD)
#define P_IGNORE(opaque) ((opaque)->btpo_flags & (BTP_DELETED|BTP_HALF_DEAD))
#define P_HAS_GARBAGE(opaque) ((opaque)->btpo_flags & BTP_HAS_GARBAGE)
#define P_INCOMPLETE_SPLIT(opaque) ((opaque)->btpo_flags & BTP_INCOMPLETE_SPLIT)
/*
* Lehman and Yao's algorithm requires a ``high key'' on every non-rightmost
* page. The high key is not a data key, but gives info about what range of
* keys is supposed to be on this page. The high key on a page is required
* to be greater than or equal to any data key that appears on the page.
* If we find ourselves trying to insert a key > 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)
/*
* XLOG records for btree operations
*
* XLOG allows to store some information in high 4 bits of log
* record xl_info field
*/
#define XLOG_BTREE_INSERT_LEAF 0x00 /* add index tuple without split */
#define XLOG_BTREE_INSERT_UPPER 0x10 /* same, on a non-leaf page */
#define XLOG_BTREE_INSERT_META 0x20 /* same, plus update metapage */
#define XLOG_BTREE_SPLIT_L 0x30 /* add index tuple with split */
#define XLOG_BTREE_SPLIT_R 0x40 /* as above, new item on right */
#define XLOG_BTREE_SPLIT_L_ROOT 0x50 /* add tuple with split of root */
#define XLOG_BTREE_SPLIT_R_ROOT 0x60 /* as above, new item on right */
#define XLOG_BTREE_DELETE 0x70 /* delete leaf index tuples for a page */
#define XLOG_BTREE_UNLINK_PAGE 0x80 /* delete a half-dead page */
#define XLOG_BTREE_UNLINK_PAGE_META 0x90 /* same, and update metapage */
#define XLOG_BTREE_NEWROOT 0xA0 /* new root page */
#define XLOG_BTREE_MARK_PAGE_HALFDEAD 0xB0 /* mark a leaf as half-dead */
#define XLOG_BTREE_VACUUM 0xC0 /* delete entries on a page during
* vacuum */
#define XLOG_BTREE_REUSE_PAGE 0xD0 /* old page is about to be reused from
* FSM */
/*
* All that we need to regenerate the meta-data page
*/
typedef struct xl_btree_metadata
{
BlockNumber root;
uint32 level;
BlockNumber fastroot;
uint32 fastlevel;
} xl_btree_metadata;
/*
* This is what we need to know about simple (without split) insert.
*
* This data record is used for INSERT_LEAF, INSERT_UPPER, INSERT_META.
* Note that INSERT_META implies it's not a leaf page.
*
* Backup Blk 0: original page (data contains the inserted tuple)
* Backup Blk 1: child's left sibling, if INSERT_UPPER or INSERT_META
* Backup Blk 2: xl_btree_metadata, if INSERT_META
*/
typedef struct xl_btree_insert
{
OffsetNumber offnum;
} xl_btree_insert;
#define SizeOfBtreeInsert (offsetof(xl_btree_insert, offnum) + sizeof(OffsetNumber))
/*
* On insert with split, we save all the items going into the right sibling
* so that we can restore it completely from the log record. This way takes
* less xlog space than the normal approach, because if we did it standardly,
* XLogInsert would almost always think the right page is new and store its
* whole page image. The left page, however, is handled in the normal
* incremental-update fashion.
*
* Note: the four XLOG_BTREE_SPLIT xl_info codes all use this data record.
* The _L and _R variants indicate whether the inserted tuple went into the
* left or right split page (and thus, whether the new item is stored or not).
* The _ROOT variants indicate that we are splitting the root page, and thus
* that a newroot record rather than an insert or split record should follow.
* Note that a split record never carries a metapage update --- we'll do that
* in the parent-level update.
*
* Backup Blk 0: original page / new left page
*
* The left page's data portion contains the new item, if it's the _L variant.
* (In the _R variants, the new item is one of the right page's tuples.)
* If level > 0, an IndexTuple representing the HIKEY of the left page
* follows. We don't need this on leaf pages, because it's the same as the
* leftmost key in the new right page.
*
* Backup Blk 1: new right page
*
* The right page's data portion contains the right page's tuples in the
* form used by _bt_restore_page.
*
* Backup Blk 2: next block (orig page's rightlink), if any
* Backup Blk 3: child's left sibling, if non-leaf split
*/
typedef struct xl_btree_split
{
uint32 level; /* tree level of page being split */
OffsetNumber firstright; /* first item moved to right page */
OffsetNumber newitemoff; /* new item's offset (useful for _L variants) */
} xl_btree_split;
#define SizeOfBtreeSplit (offsetof(xl_btree_split, newitemoff) + sizeof(OffsetNumber))
/*
* This is what we need to know about delete of individual leaf index tuples.
* The WAL record can represent deletion of any number of index tuples on a
* single index page when *not* executed by VACUUM.
*
* Backup Blk 0: index page
*/
typedef struct xl_btree_delete
{
RelFileNode hnode; /* RelFileNode of the heap the index currently
* points at */
int nitems;
/* TARGET OFFSET NUMBERS FOLLOW AT THE END */
} xl_btree_delete;
#define SizeOfBtreeDelete (offsetof(xl_btree_delete, nitems) + sizeof(int))
/*
* This is what we need to know about page reuse within btree.
*/
typedef struct xl_btree_reuse_page
{
RelFileNode node;
BlockNumber block;
TransactionId latestRemovedXid;
} xl_btree_reuse_page;
#define SizeOfBtreeReusePage (sizeof(xl_btree_reuse_page))
/*
* This is what we need to know about vacuum of individual leaf index tuples.
* The WAL record can represent deletion of any number of index tuples on a
* single index page when executed by VACUUM.
*
* For MVCC scans, lastBlockVacuumed will be set to InvalidBlockNumber.
* For a non-MVCC index scans there is an additional correctness requirement
* for applying these changes during recovery, which is that we must do one
* of these two things for every block in the index:
* * lock the block for cleanup and apply any required changes
* * EnsureBlockUnpinned()
* The purpose of this is to ensure that no index scans started before we
* finish scanning the index are still running by the time we begin to remove
* heap tuples.
*
* Any changes to any one block are registered on just one WAL record. All
* blocks that we need to run EnsureBlockUnpinned() are listed as a block range
* starting from the last block vacuumed through until this one. Individual
* block numbers aren't given.
*
* Note that the *last* WAL record in any vacuum of an index is allowed to
* have a zero length array of offsets. Earlier records must have at least one.
*/
typedef struct xl_btree_vacuum
{
BlockNumber lastBlockVacuumed;
/* TARGET OFFSET NUMBERS FOLLOW */
} xl_btree_vacuum;
#define SizeOfBtreeVacuum (offsetof(xl_btree_vacuum, lastBlockVacuumed) + sizeof(BlockNumber))
/*
* This is what we need to know about marking an empty branch for deletion.
* The target identifies the tuple removed from the parent page (note that we
* remove this tuple's downlink and the *following* tuple's key). Note that
* the leaf page is empty, so we don't need to store its content --- it is
* just reinitialized during recovery using the rest of the fields.
*
* Backup Blk 0: leaf block
* Backup Blk 1: top parent
*/
typedef struct xl_btree_mark_page_halfdead
{
OffsetNumber poffset; /* deleted tuple id in parent page */
/* information needed to recreate the leaf page: */
BlockNumber leafblk; /* leaf block ultimately being deleted */
BlockNumber leftblk; /* leaf block's left sibling, if any */
BlockNumber rightblk; /* leaf block's right sibling */
BlockNumber topparent; /* topmost internal page in the branch */
} xl_btree_mark_page_halfdead;
#define SizeOfBtreeMarkPageHalfDead (offsetof(xl_btree_mark_page_halfdead, topparent) + sizeof(BlockNumber))
/*
* This is what we need to know about deletion of a btree page. Note we do
* not store any content for the deleted page --- it is just rewritten as empty
* during recovery, apart from resetting the btpo.xact.
*
* Backup Blk 0: target block being deleted
* Backup Blk 1: target block's left sibling, if any
* Backup Blk 2: target block's right sibling
* Backup Blk 3: leaf block (if different from target)
* Backup Blk 4: metapage (if rightsib becomes new fast root)
*/
typedef struct xl_btree_unlink_page
{
BlockNumber leftsib; /* target block's left sibling, if any */
BlockNumber rightsib; /* target block's right sibling */
/*
* Information needed to recreate the leaf page, when target is an
* internal page.
*/
BlockNumber leafleftsib;
BlockNumber leafrightsib;
BlockNumber topparent; /* next child down in the branch */
TransactionId btpo_xact; /* value of btpo.xact for use in recovery */
/* xl_btree_metadata FOLLOWS IF XLOG_BTREE_UNLINK_PAGE_META */
} xl_btree_unlink_page;
#define SizeOfBtreeUnlinkPage (offsetof(xl_btree_unlink_page, btpo_xact) + sizeof(TransactionId))
/*
* New root log record. There are zero tuples if this is to establish an
* empty root, or two if it is the result of splitting an old root.
*
* Note that although this implies rewriting the metadata page, we don't need
* an xl_btree_metadata record --- the rootblk and level are sufficient.
*
* Backup Blk 0: new root page (2 tuples as payload, if splitting old root)
* Backup Blk 1: left child (if splitting an old root)
* Backup Blk 2: metapage
*/
typedef struct xl_btree_newroot
{
BlockNumber rootblk; /* location of new root (redundant with blk 0) */
uint32 level; /* its tree level */
} xl_btree_newroot;
#define SizeOfBtreeNewroot (offsetof(xl_btree_newroot, level) + sizeof(uint32))
/*
* 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.
*/
#define BTORDER_PROC 1
#define BTSORTSUPPORT_PROC 2
#define BTNProcs 2
/*
* 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, downlink)
* pairs from internal pages onto a private stack. If we split a
* leaf, we use this stack to walk back up the tree and insert data
* into parent pages (and possibly to split them, too). Lehman and
* Yao's update algorithm guarantees that under no circumstances can
* our private stack give us an irredeemably bad picture up the tree.
* Again, see the paper for details.
*/
typedef struct BTStackData
{
BlockNumber bts_blkno;
OffsetNumber bts_offset;
IndexTupleData bts_btentry;
struct BTStackData *bts_parent;
} BTStackData;
typedef BTStackData *BTStack;
/*
* 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) */
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)
/*
* prototypes for functions in nbtree.c (external entry points for btree)
*/
extern Datum bthandler(PG_FUNCTION_ARGS);
extern IndexBuildResult *btbuild(Relation heap, Relation index,
struct IndexInfo *indexInfo);
extern void btbuildempty(Relation index);
extern bool btinsert(Relation rel, Datum *values, bool *isnull,
ItemPointer ht_ctid, Relation heapRel,
IndexUniqueCheck checkUnique);
extern IndexScanDesc btbeginscan(Relation rel, int nkeys, int norderbys);
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 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 functions in nbtinsert.c
*/
extern bool _bt_doinsert(Relation rel, IndexTuple itup,
IndexUniqueCheck checkUnique, Relation heapRel);
extern Buffer _bt_getstackbuf(Relation rel, BTStack stack, int access);
extern void _bt_finish_split(Relation rel, Buffer bbuf, BTStack stack);
/*
* prototypes for functions in nbtpage.c
*/
extern void _bt_initmetapage(Page page, BlockNumber rootbknum, uint32 level);
extern Buffer _bt_getroot(Relation rel, int access);
extern Buffer _bt_gettrueroot(Relation rel);
extern int _bt_getrootheight(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,
int keysz, ScanKey scankey, bool nextkey,
Buffer *bufP, int access, Snapshot snapshot);
extern Buffer _bt_moveright(Relation rel, Buffer buf, int keysz,
ScanKey scankey, bool nextkey, bool forupdate, BTStack stack,
int access, Snapshot snapshot);
extern OffsetNumber _bt_binsrch(Relation rel, Buffer buf, int keysz,
ScanKey scankey, bool nextkey);
extern int32 _bt_compare(Relation rel, int keysz, ScanKey scankey,
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 ScanKey _bt_mkscankey(Relation rel, IndexTuple itup);
extern ScanKey _bt_mkscankey_nodata(Relation rel);
extern void _bt_freeskey(ScanKey skey);
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 IndexTuple _bt_checkkeys(IndexScanDesc scan,
Page page, OffsetNumber offnum,
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);
/*
* prototypes for functions in nbtvalidate.c
*/
extern bool btvalidate(Oid opclassoid);
/*
* prototypes for functions in nbtsort.c
*/
typedef struct BTSpool BTSpool; /* opaque type known only within nbtsort.c */
extern BTSpool *_bt_spoolinit(Relation heap, Relation index,
bool isunique, bool isdead);
extern void _bt_spooldestroy(BTSpool *btspool);
extern void _bt_spool(BTSpool *btspool, ItemPointer self,
Datum *values, bool *isnull);
extern void _bt_leafbuild(BTSpool *btspool, BTSpool *spool2);
/*
* prototypes for functions in nbtxlog.c
*/
extern void btree_redo(XLogReaderState *record);
extern void btree_desc(StringInfo buf, XLogReaderState *record);
extern const char *btree_identify(uint8 info);
#endif /* NBTREE_H */
|