about summary refs log tree commit diff
path: root/db2/include/btree.h
blob: 5cf4224ae627908b683e39e880599f867c22e3c1 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997
 *	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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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.
 *
 *	@(#)btree.h	10.16 (Sleepycat) 8/24/97
 */

/* Forward structure declarations. */
struct __btree;		typedef struct __btree BTREE;
struct __cursor;	typedef struct __cursor CURSOR;
struct __epg;		typedef struct __epg EPG;
struct __rcursor;	typedef struct __rcursor RCURSOR;
struct __recno;		typedef struct __recno RECNO;

#undef	DEFMINKEYPAGE			/* Minimum keys per page */
#define	DEFMINKEYPAGE	 (2)

#undef	ISINTERNAL			/* If an internal page. */
#define	ISINTERNAL(p)	(TYPE(p) == P_IBTREE || TYPE(p) ==  P_IRECNO)
#undef	ISLEAF				/* If a leaf page. */
#define	ISLEAF(p)	(TYPE(p) == P_LBTREE || TYPE(p) ==  P_LRECNO)

/* Allocate and discard thread structures. */
#define	GETHANDLE(dbp, set_txn, dbpp, ret) {				\
	if (F_ISSET(dbp, DB_AM_THREAD)) {				\
		if ((ret = __db_gethandle(dbp, __bam_bdup, dbpp)) != 0)	\
			return (ret);					\
	} else								\
		*dbpp = dbp;						\
	*dbpp->txn = set_txn;						\
}
#define	PUTHANDLE(dbp) {						\
	dbp->txn = NULL;						\
	if (F_ISSET(dbp, DB_AM_THREAD))					\
		__db_puthandle(dbp);					\
}

/*
 * If doing transactions we have to hold the locks associated with a data item
 * from a page for the entire transaction.  However, we don't have to hold the
 * locks associated with walking the tree.  Distinguish between the two so that
 * we don't tie up the internal pages of the tree longer than necessary.
 */
#define	__BT_LPUT(dbp, lock)						\
	(F_ISSET((dbp), DB_AM_LOCKING) ?				\
	    lock_put((dbp)->dbenv->lk_info, lock) : 0)
#define	__BT_TLPUT(dbp, lock)						\
	(F_ISSET((dbp), DB_AM_LOCKING) && (dbp)->txn == NULL ?		\
	    lock_put((dbp)->dbenv->lk_info, lock) : 0)

/*
 * Flags to __bt_search() and __rec_search().
 *
 * 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		0x0001		/* Read locks. */
#define	S_WRITE		0x0002		/* Write locks. */

#define	S_APPEND	0x0040		/* Append to the tree. */
#define	S_DELNO		0x0080		/* Don't return deleted items. */
#define	S_DUPFIRST	0x0100		/* Return first duplicate. */
#define	S_DUPLAST	0x0200		/* Return last duplicate. */
#define	S_EXACT		0x0400		/* Exact items only. */
#define	S_PARENT	0x0800		/* Lock page pair. */

#define	S_DELETE	(S_WRITE | S_DUPFIRST | S_DELNO | S_EXACT)
#define	S_FIND		(S_READ | S_DUPFIRST | S_DELNO)
#define	S_INSERT	(S_WRITE | S_DUPLAST)
#define	S_KEYFIRST	(S_WRITE | S_DUPFIRST)
#define	S_KEYLAST	(S_WRITE | S_DUPLAST)
#define	S_WRPAIR	(S_WRITE | S_DUPLAST | S_PARENT)

/*
 * Flags to __bam_iitem().
 */
#define	BI_NEWKEY	0x01		/* New key. */
#define	BI_DELETED	0x02		/* Key/data pair only placeholder. */

/*
 * Various routines pass around page references.  A page reference can be a
 * pointer to the page or a page number; for either, an indx can designate
 * an item on the page.
 */
struct __epg {
	PAGE	 *page;			/* The page. */
	db_indx_t indx;			/* The index on the page. */
	DB_LOCK	  lock;			/* The page's lock. */
};

/*
 * Btree cursor.
 *
 * Arguments passed to __bam_ca_replace().
 */
typedef enum {
	REPLACE_SETUP,
	REPLACE_SUCCESS,
	REPLACE_FAILED
} ca_replace_arg;
struct __cursor {
	DBC		*dbc;		/* Enclosing DBC. */

	PAGE		*page;		/* Cursor page. */

	db_pgno_t	 pgno;		/* Page. */
	db_indx_t	 indx;		/* Page item ref'd by the cursor. */

	db_pgno_t	 dpgno;		/* Duplicate page. */
	db_indx_t	 dindx;		/* Page item ref'd by the cursor. */

	DB_LOCK		 lock;		/* Cursor read lock. */
	db_lockmode_t	 mode;		/* Lock mode. */

	/*
	 * If a cursor record is deleted, the key/data pair has to remain on
	 * the page so that subsequent inserts/deletes don't interrupt the
	 * cursor progression through the file.  This results in interesting
	 * cases when "standard" operations, e.g., dbp->put() are done in the
	 * context of "deleted" cursors.
	 *
	 * C_DELETED -- The item referenced by the cursor has been "deleted"
	 *		but not physically removed from the page.
	 * C_REPLACE -- The "deleted" item referenced by a cursor has been
	 *		replaced by a dbp->put(), so the cursor is no longer
	 *		responsible for physical removal from the page.
	 * C_REPLACE_SETUP --
	 *		We are about to overwrite a "deleted" item, flag any
	 *		cursors referencing it for transition to C_REPLACE
	 *		state.
	 */
#define	C_DELETED	0x0001
#define	C_REPLACE	0x0002
#define	C_REPLACE_SETUP	0x0004
	u_int32_t	 flags;
};

/*
 * Recno cursor.
 *
 * Arguments passed to __ram_ca().
 */
typedef enum {
	CA_DELETE,
	CA_IAFTER,
	CA_IBEFORE
} ca_recno_arg;
struct __rcursor {
	DBC		*dbc;		/* Enclosing DBC. */

	db_recno_t	 recno;		/* Current record number. */

	/*
	 * Cursors referencing "deleted" records are positioned between
	 * two records, and so must be specially adjusted until they are
	 * moved.
	 */
#define	CR_DELETED	0x0001		/* Record deleted. */
	u_int32_t	 flags;
};

/*
 * We maintain a stack of the pages that we're locking in the tree.  Btree's
 * (currently) only save two levels of the tree at a time, so the default
 * stack is always large enough.  Recno trees have to lock the entire tree to
 * do inserts/deletes, however.  Grow the stack as necessary.
 */
#undef	BT_STK_CLR
#define	BT_STK_CLR(t)							\
	((t)->bt_csp = (t)->bt_sp)

#undef	BT_STK_ENTER
#define	BT_STK_ENTER(t, pagep, page_indx, lock, ret) do {		\
	if ((ret =							\
	    (t)->bt_csp == (t)->bt_esp ? __bam_stkgrow(t) : 0) == 0) {	\
		(t)->bt_csp->page = pagep;				\
		(t)->bt_csp->indx = page_indx;				\
		(t)->bt_csp->lock = lock;				\
	}								\
} while (0)

#undef	BT_STK_PUSH
#define	BT_STK_PUSH(t, pagep, page_indx, lock, ret) do {		\
	BT_STK_ENTER(t, pagep, page_indx, lock, ret);			\
	++(t)->bt_csp;							\
} while (0)

#undef	BT_STK_POP
#define	BT_STK_POP(t)							\
	((t)->bt_csp == (t)->bt_stack ? NULL : --(t)->bt_csp)

/*
 * The in-memory recno data structure.
 *
 * !!!
 * 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.
 */
#undef	RECNO_OOB
#define	RECNO_OOB	0		/* Illegal record number. */

struct __recno {
	int		 re_delim;	/* Variable-length delimiting byte. */
	int		 re_pad;	/* Fixed-length padding byte. */
	u_int32_t	 re_len;	/* Length for fixed-length records. */

	char		*re_source;	/* Source file name. */
	int		 re_fd;		/* Source file descriptor */
	db_recno_t	 re_last;	/* Last record number read. */
	void		*re_cmap;	/* Current point in mapped space. */
	void		*re_smap;	/* Start of mapped space. */
	void		*re_emap;	/* End of mapped space. */
	size_t		 re_msize;	/* Size of mapped region. */
					/* Recno input function. */
	int (*re_irec) __P((DB *, db_recno_t));

#define	RECNO_EOF	0x0001		/* EOF on backing source file. */
#define	RECNO_MODIFIED	0x0002		/* Tree was modified. */
	u_int32_t	 flags;
};

/*
 * The in-memory btree data structure.
 */
struct __btree {
/*
 * These fields are per-thread and are initialized when the BTREE structure
 * is created.
 */
	db_pgno_t	 bt_lpgno;	/* Last insert location. */

	DBT		 bt_rkey;	/* Returned key. */
	DBT		 bt_rdata;	/* Returned data. */

	EPG		*bt_sp;		/* Stack pointer. */
	EPG	 	*bt_csp;	/* Current stack entry. */
	EPG		*bt_esp;	/* End stack pointer. */
	EPG		 bt_stack[5];

	RECNO		*bt_recno;	/* Private recno structure. */

	DB_BTREE_LSTAT lstat;		/* Btree local statistics. */

/*
 * These fields are copied from the original BTREE structure and never
 * change.
 */
	db_indx_t 	 bt_maxkey;	/* Maximum keys per page. */
	db_indx_t 	 bt_minkey;	/* Minimum keys per page. */

	int (*bt_compare)		/* Comparison function. */
	    __P((const DBT *, const DBT *));
	size_t(*bt_prefix)		/* Prefix function. */
	    __P((const DBT *, const DBT *));

	db_indx_t	 bt_ovflsize;	/* Maximum key/data on-page size. */
};

#include "btree_auto.h"
#include "btree_ext.h"
#include "db_am.h"
#include "common_ext.h"