/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996-2002
* Sleepycat Software. All rights reserved.
*/
/*
* Copyright (c) 1990, 1993, 1994, 1995, 1996
* Keith Bostic. All rights reserved.
*/
/*
* Copyright (c) 1990, 1993, 1994, 1995
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Mike Olson.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: btree.h,v 11.45 2002/08/06 06:11:21 bostic Exp $
*/
#ifndef _DB_BTREE_H_
#define _DB_BTREE_H_
/* Forward structure declarations. */
struct __btree; typedef struct __btree BTREE;
struct __cursor; typedef struct __cursor BTREE_CURSOR;
struct __epg; typedef struct __epg EPG;
struct __recno; typedef struct __recno RECNO;
#define DEFMINKEYPAGE (2)
/*
* A recno order of 0 indicates that we don't have an order, not that we've
* an order less than 1.
*/
#define INVALID_ORDER 0
#define ISINTERNAL(p) (TYPE(p) == P_IBTREE || TYPE(p) == P_IRECNO)
#define ISLEAF(p) (TYPE(p) == P_LBTREE || \
TYPE(p) == P_LRECNO || TYPE(p) == P_LDUP)
/* Flags for __bam_cadjust_log(). */
#define CAD_UPDATEROOT 0x01 /* Root page count was updated. */
/* Flags for __bam_split_log(). */
#define SPL_NRECS 0x01 /* Split tree has record count. */
/* Flags for __bam_iitem(). */
#define BI_DELETED 0x01 /* Key/data pair only placeholder. */
/* Flags for __bam_stkrel(). */
#define STK_CLRDBC 0x01 /* Clear dbc->page reference. */
#define STK_NOLOCK 0x02 /* Don't retain locks. */
/* Flags for __ram_ca(). These get logged, so make the values explicit. */
typedef enum {
CA_DELETE = 0, /* Delete the current record. */
CA_IAFTER = 1, /* Insert before the current record. */
CA_IBEFORE = 2, /* Insert after the current record. */
CA_ICURRENT = 3 /* Overwrite the current record. */
} ca_recno_arg;
/*
* Flags for __bam_search() and __bam_rsearch().
*
* Note, internal page searches must find the largest record less than key in
* the tree so that descents work. Leaf page searches must find the smallest
* record greater than key so that the returned index is the record's correct
* position for insertion.
*
* The flags parameter to the search routines describes three aspects of the
* search: the type of locking required (including if we're locking a pair of
* pages), the item to return in the presence of duplicates and whether or not
* to return deleted entries. To simplify both the mnemonic representation
* and the code that checks for various cases, we construct a set of bitmasks.
*/
#define S_READ 0x00001 /* Read locks. */
#define S_WRITE 0x00002 /* Write locks. */
#define S_APPEND 0x00040 /* Append to the tree. */
#define S_DELNO 0x00080 /* Don't return deleted items. */
#define S_DUPFIRST 0x00100 /* Return first duplicate. */
#define S_DUPLAST 0x00200 /* Return last duplicate. */
#define S_EXACT 0x00400 /* Exact items only. */
#define S_PARENT 0x00800 /* Lock page pair. */
#define S_STACK 0x01000 /* Need a complete stack. */
#define S_PAST_EOF 0x02000 /* If doing insert search (or keyfirst
* or keylast operations), or a split
* on behalf of an insert, it's okay to
* return an entry one past end-of-page.
*/
#define S_STK_ONLY 0x04000 /* Just return info in the stack */
#define S_DELETE (S_WRITE | S_DUPFIRST | S_DELNO | S_EXACT | S_STACK)
#define S_FIND (S_READ | S_DUPFIRST | S_DELNO)
#define S_FIND_WR (S_WRITE | S_DUPFIRST | S_DELNO)
#define S_INSERT (S_WRITE | S_DUPLAST | S_PAST_EOF | S_STACK)
#define S_KEYFIRST (S_WRITE | S_DUPFIRST | S_PAST_EOF | S_STACK)
#define S_KEYLAST (S_WRITE | S_DUPLAST | S_PAST_EOF | S_STACK)
#define S_WRPAIR (S_WRITE | S_DUPLAST | S_PAST_EOF | S_PARENT)
/*
* Various routines pass around page references. A page reference is
* a pointer to the page, and the indx indicates an item on the page.
* Each page reference may include a lock.
*/
struct __epg {
PAGE *page; /* The page. */
db_indx_t indx; /* The index on the page. */
db_indx_t entries; /* The number of entries on page */
DB_LOCK lock; /* The page's lock. */
db_lockmode_t lock_mode; /* The lock mode. */
};
/*
* We maintain a stack of the pages that we're locking in the tree. Grow
* the stack as necessary.
*
* XXX
* Temporary fix for #3243 -- clear the page and lock from the stack entry.
* The correct fix is to never release a stack that doesn't hold items.
*/
#define BT_STK_CLR(c) do { \
(c)->csp = (c)->sp; \
(c)->csp->page = NULL; \
LOCK_INIT((c)->csp->lock); \
} while (0)
#define BT_STK_ENTER(dbenv, c, pagep, page_indx, l, mode, ret) do { \
if ((ret = \
(c)->csp == (c)->esp ? __bam_stkgrow(dbenv, c) : 0) == 0) { \
(c)->csp->page = pagep; \
(c)->csp->indx = page_indx; \
(c)->csp->entries = NUM_ENT(pagep); \
(c)->csp->lock = l; \
(c)->csp->lock_mode = mode; \
} \
} while (0)
#define BT_STK_PUSH(dbenv, c, pagep, page_indx, lock, mode, ret) do { \
BT_STK_ENTER(dbenv, c, pagep, page_indx, lock, mode, ret); \
++(c)->csp; \
} while (0)
#define BT_STK_NUM(dbenv, c, pagep, page_indx, ret) do { \
if ((ret = \
(c)->csp == (c)->esp ? __bam_stkgrow(dbenv, c) : 0) == 0) { \
(c)->csp->page = NULL; \
(c)->csp->indx = page_indx; \
(c)->csp->entries = NUM_ENT(pagep); \
LOCK_INIT((c)->csp->lock); \
(c)->csp->lock_mode = DB_LOCK_NG; \
} \
} while (0)
#define BT_STK_NUMPUSH(dbenv, c, pagep, page_indx, ret) do { \
BT_STK_NUM(dbenv, cp, pagep, page_indx, ret); \
++(c)->csp; \
} while (0)
#define BT_STK_POP(c) \
((c)->csp == (c)->sp ? NULL : --(c)->csp)
/* Btree/Recno cursor. */
struct __cursor {
/* struct __dbc_internal */
__DBC_INTERNAL
/* btree private part */
EPG *sp; /* Stack pointer. */
EPG *csp; /* Current stack entry. */
EPG *esp; /* End stack pointer. */
EPG stack[5];
db_indx_t ovflsize; /* Maximum key/data on-page size. */
db_recno_t recno; /* Current record number. */
u_int32_t order; /* Relative order among deleted curs. */
/*
* Btree:
* We set a flag in the cursor structure if the underlying object has
* been deleted. It's not strictly necessary, we could get the same
* information by looking at the page itself, but this method doesn't
* require us to retrieve the page on cursor delete.
*
* Recno:
* When renumbering recno databases during deletes, cursors referencing
* "deleted" records end up positioned between two records, and so must
* be specially adjusted on the next operation.
*/
#define C_DELETED 0x0001 /* Record was deleted. */
/*
* There are three tree types that require maintaining record numbers.
* Recno AM trees, Btree AM trees for which the DB_RECNUM flag was set,
* and Btree off-page duplicate trees.
*/
#define C_RECNUM 0x0002 /* Tree requires record counts. */
/*
* Recno trees have immutable record numbers by default, but optionally
* support mutable record numbers. Off-page duplicate Recno trees have
* mutable record numbers. All Btrees with record numbers (including
* off-page duplicate trees) are mutable by design, no flag is needed.
*/
#define C_RENUMBER 0x0004 /* Tree records are mutable. */
u_int32_t flags;
};
/*
* Threshhold value, as a function of bt_minkey, of the number of
* bytes a key/data pair can use before being placed on an overflow
* page. Assume every item requires the maximum alignment for
* padding, out of sheer paranoia.
*/
#define B_MINKEY_TO_OVFLSIZE(dbp, minkey, pgsize) \
((u_int16_t)(((pgsize) - P_OVERHEAD(dbp)) / ((minkey) * P_INDX) -\
(BKEYDATA_PSIZE(0) + ALIGN(1, sizeof(int32_t)))))
/*
* The maximum space that a single item can ever take up on one page.
* Used by __bam_split to determine whether a split is still necessary.
*/
#define B_MAX(a,b) (((a) > (b)) ? (a) : (b))
#define B_MAXSIZEONPAGE(ovflsize) \
(B_MAX(BOVERFLOW_PSIZE, BKEYDATA_PSIZE(ovflsize)))
/*
* The in-memory, per-tree btree/recno data structure.
*/
struct __btree { /* Btree access method. */
/*
* !!!
* These fields are write-once (when the structure is created) and
* so are ignored as far as multi-threading is concerned.
*/
db_pgno_t bt_meta; /* Database meta-data page. */
db_pgno_t bt_root; /* Database root page. */
u_int32_t bt_maxkey; /* Maximum keys per page. */
u_int32_t bt_minkey; /* Minimum keys per page. */
/* Btree comparison function. */
int (*bt_compare) __P((DB *, const DBT *, const DBT *));
/* Btree prefix function. */
size_t (*bt_prefix) __P((DB *, const DBT *, const DBT *));
/* Recno access method. */
int re_pad; /* Fixed-length padding byte. */
int re_delim; /* Variable-length delimiting byte. */
u_int32_t re_len; /* Length for fixed-length records. */
char *re_source; /* Source file name. */
/*
* !!!
* The bt_lpgno field is NOT protected by any mutex, and for this
* reason must be advisory only, so, while it is read/written by
* multiple threads, DB is completely indifferent to the quality
* of its information.
*/
db_pgno_t bt_lpgno; /* Last insert location. */
/*
* !!!
* The re_modified field is NOT protected by any mutex, and for this
* reason cannot be anything more complicated than a zero/non-zero
* value. The actual writing of the backing source file cannot be
* threaded, so clearing the flag isn't a problem.
*/
int re_modified; /* If the tree was modified. */
/*
* !!!
* These fields are ignored as far as multi-threading is concerned.
* There are no transaction semantics associated with backing files,
* nor is there any thread protection.
*/
FILE *re_fp; /* Source file handle. */
int re_eof; /* Backing source file EOF reached. */
db_recno_t re_last; /* Last record number read. */
};
/*
* Modes for the __bam_curadj recovery records (btree_curadj).
* These appear in log records, so we wire the values and
* do not leave it up to the compiler.
*/
typedef enum {
DB_CA_DI = 1,
DB_CA_DUP = 2,
DB_CA_RSPLIT = 3,
DB_CA_SPLIT = 4
} db_ca_mode;
#include "dbinc_auto/btree_auto.h"
#include "dbinc_auto/btree_ext.h"
#include "dbinc/db_am.h"
#endif /* !_DB_BTREE_H_ */
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