aboutsummaryrefslogtreecommitdiff
path: root/db2/btree/bt_open.c
blob: f5974ec61ee70abb6ad6286832639d66430eee22 (plain)
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
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997, 1998
 *	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.
 */

#include "config.h"

#ifndef lint
static const char sccsid[] = "@(#)bt_open.c	10.27 (Sleepycat) 5/6/98";
#endif /* not lint */

/*
 * Implementation of btree access method for 4.4BSD.
 *
 * The design here was originally based on that of the btree access method
 * used in the Postgres database system at UC Berkeley.  This implementation
 * is wholly independent of the Postgres code.
 */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <errno.h>
#include <limits.h>
#include <string.h>
#endif

#include "db_int.h"
#include "db_page.h"
#include "btree.h"

static int __bam_keyalloc __P((BTREE *));
static int __bam_setmeta __P((DB *, BTREE *));

/*
 * __bam_open --
 *	Open a btree.
 *
 * PUBLIC: int __bam_open __P((DB *, DBTYPE, DB_INFO *));
 */
int
__bam_open(dbp, type, dbinfo)
	DB *dbp;
	DBTYPE type;
	DB_INFO *dbinfo;
{
	BTREE *t;
	int ret;

	/* Allocate the btree internal structure. */
	if ((t = (BTREE *)__db_calloc(1, sizeof(BTREE))) == NULL)
		return (ENOMEM);

	t->bt_sp = t->bt_csp = t->bt_stack;
	t->bt_esp = t->bt_stack + sizeof(t->bt_stack) / sizeof(t->bt_stack[0]);

	if ((type == DB_RECNO || F_ISSET(dbp, DB_BT_RECNUM)) &&
	    (ret = __bam_keyalloc(t)) != 0)
		goto err;

	/*
	 * Intention is to make sure all of the user's selections are okay
	 * here and then use them without checking.
	 */
	if (dbinfo != NULL) {
		/* Minimum number of keys per page. */
		if (dbinfo->bt_minkey == 0)
			t->bt_minkey = DEFMINKEYPAGE;
		else {
			if (dbinfo->bt_minkey < 2)
				goto einval;
			t->bt_minkey = dbinfo->bt_minkey;
		}

		/* Maximum number of keys per page. */
		if (dbinfo->bt_maxkey == 0)
			t->bt_maxkey = 0;
		else {
			if (dbinfo->bt_maxkey < 1)
				goto einval;
			t->bt_maxkey = dbinfo->bt_maxkey;
		}

		/*
		 * If no comparison, use default comparison.  If no comparison
		 * and no prefix, use default prefix.  (We can't default the
		 * prefix if the user supplies a comparison routine; shortening
		 * the keys may break their comparison algorithm.)
		 */
		t->bt_compare = dbinfo->bt_compare == NULL ?
		    __bam_defcmp : dbinfo->bt_compare;
		t->bt_prefix = dbinfo->bt_prefix == NULL ?
		    (dbinfo->bt_compare == NULL ?
		    __bam_defpfx : NULL) : dbinfo->bt_prefix;
	} else {
		t->bt_minkey = DEFMINKEYPAGE;
		t->bt_compare = __bam_defcmp;
		t->bt_prefix = __bam_defpfx;
	}

	/* Initialize the remaining fields of the DB. */
	dbp->type = type;
	dbp->internal = t;
	dbp->cursor = __bam_cursor;
	dbp->del = __bam_delete;
	dbp->get = __bam_get;
	dbp->put = __bam_put;
	dbp->stat = __bam_stat;
	dbp->sync = __bam_sync;

	/*
	 * The btree data structure requires that at least two key/data pairs
	 * can fit on a page, but other than that there's no fixed requirement.
	 * Translate the minimum number of items into the bytes a key/data pair
	 * can use before being placed on an overflow page.  We calculate for
	 * the worst possible alignment by assuming every item requires the
	 * maximum alignment for padding.
	 *
	 * Recno uses the btree bt_ovflsize value -- it's close enough.
	 */
	t->bt_ovflsize = (dbp->pgsize - P_OVERHEAD) / (t->bt_minkey * P_INDX)
	    - (BKEYDATA_PSIZE(0) + ALIGN(1, 4));

	/* Create a root page if new tree. */
	if ((ret = __bam_setmeta(dbp, t)) != 0)
		goto err;

	return (0);

einval:	ret = EINVAL;

err:	if (t != NULL) {
		/* If we allocated room for key/data return, discard it. */
		if (t->bt_rkey.data != NULL)
			__db_free(t->bt_rkey.data);

		FREE(t, sizeof(BTREE));
	}
	return (ret);
}

/*
 * __bam_bdup --
 *	Create a BTREE handle for a threaded DB handle.
 *
 * PUBLIC: int __bam_bdup __P((DB *, DB *));
 */
int
__bam_bdup(orig, new)
	DB *orig, *new;
{
	BTREE *t, *ot;
	int ret;

	ot = orig->internal;

	if ((t = (BTREE *)__db_calloc(1, sizeof(*t))) == NULL)
		return (ENOMEM);

	/*
	 * !!!
	 * Ignore the cursor queue, only the first DB has attached cursors.
	 */

	t->bt_sp = t->bt_csp = t->bt_stack;
	t->bt_esp = t->bt_stack + sizeof(t->bt_stack) / sizeof(t->bt_stack[0]);

	if ((orig->type == DB_RECNO || F_ISSET(orig, DB_BT_RECNUM)) &&
	    (ret = __bam_keyalloc(t)) != 0) {
		FREE(t, sizeof(*t));
		return (ret);
	}

	t->bt_maxkey = ot->bt_maxkey;
	t->bt_minkey = ot->bt_minkey;
	t->bt_compare = ot->bt_compare;
	t->bt_prefix = ot->bt_prefix;
	t->bt_ovflsize = ot->bt_ovflsize;

	/*
	 * !!!
	 * The entire RECNO structure is shared.  If it breaks, the application
	 * was misusing it to start with.
	 */
	t->bt_recno = ot->bt_recno;

	new->internal = t;

	return (0);
}

/*
 * __bam_keyalloc --
 *	Allocate return memory for recno keys.
 */
static int
__bam_keyalloc(t)
	BTREE *t;
{
	/*
	 * Recno keys are always the same size, and we don't want to have
	 * to check for space on each return.  Allocate it now.
	 */
	if ((t->bt_rkey.data = (void *)__db_malloc(sizeof(db_recno_t))) == NULL)
		return (ENOMEM);
	t->bt_rkey.ulen = sizeof(db_recno_t);
	return (0);
}

/*
 * __bam_setmeta --
 *	Check (and optionally create) a tree.
 */
static int
__bam_setmeta(dbp, t)
	DB *dbp;
	BTREE *t;
{
	BTMETA *meta;
	PAGE *root;
	DB_LOCK metalock, rootlock;
	db_pgno_t pgno;
	int ret;

	/* Get, and optionally create the metadata page. */
	pgno = PGNO_METADATA;
	if ((ret =
	    __bam_lget(dbp, 0, PGNO_METADATA, DB_LOCK_WRITE, &metalock)) != 0)
		return (ret);
	if ((ret =
	    __bam_pget(dbp, (PAGE **)&meta, &pgno, DB_MPOOL_CREATE)) != 0) {
		(void)__BT_LPUT(dbp, metalock);
		return (ret);
	}

	/*
	 * If the magic number is correct, we're not creating the tree.
	 * Correct any fields that may not be right.  Note, all of the
	 * local flags were set by db_open(3).
	 */
	if (meta->magic != 0) {
		t->bt_maxkey = meta->maxkey;
		t->bt_minkey = meta->minkey;

		(void)memp_fput(dbp->mpf, (PAGE *)meta, 0);
		(void)__BT_LPUT(dbp, metalock);
		return (0);
	}

	/* Initialize the tree structure metadata information. */
	memset(meta, 0, sizeof(BTMETA));
	ZERO_LSN(meta->lsn);
	meta->pgno = PGNO_METADATA;
	meta->magic = DB_BTREEMAGIC;
	meta->version = DB_BTREEVERSION;
	meta->pagesize = dbp->pgsize;
	meta->maxkey = t->bt_maxkey;
	meta->minkey = t->bt_minkey;
	meta->free = PGNO_INVALID;
	if (dbp->type == DB_RECNO)
		F_SET(meta, BTM_RECNO);
	if (F_ISSET(dbp, DB_AM_DUP))
		F_SET(meta, BTM_DUP);
	if (F_ISSET(dbp, DB_RE_FIXEDLEN))
		F_SET(meta, BTM_FIXEDLEN);
	if (F_ISSET(dbp, DB_BT_RECNUM))
		F_SET(meta, BTM_RECNUM);
	if (F_ISSET(dbp, DB_RE_RENUMBER))
		F_SET(meta, BTM_RENUMBER);
	memcpy(meta->uid, dbp->lock.fileid, DB_FILE_ID_LEN);

	/* Create and initialize a root page. */
	pgno = PGNO_ROOT;
	if ((ret =
	    __bam_lget(dbp, 0, PGNO_ROOT, DB_LOCK_WRITE, &rootlock)) != 0)
		return (ret);
	if ((ret = __bam_pget(dbp, &root, &pgno, DB_MPOOL_CREATE)) != 0) {
		(void)__BT_LPUT(dbp, rootlock);
		return (ret);
	}
	P_INIT(root, dbp->pgsize, PGNO_ROOT, PGNO_INVALID,
	    PGNO_INVALID, 1, dbp->type == DB_RECNO ? P_LRECNO : P_LBTREE);
	ZERO_LSN(root->lsn);

	/* Release the metadata and root pages. */
	if ((ret = memp_fput(dbp->mpf, (PAGE *)meta, DB_MPOOL_DIRTY)) != 0)
		return (ret);
	if ((ret = memp_fput(dbp->mpf, root, DB_MPOOL_DIRTY)) != 0)
		return (ret);

	/*
	 * Flush the metadata and root pages to disk -- since the user can't
	 * transaction protect open, the pages have to exist during recovery.
	 *
	 * XXX
	 * It's not useful to return not-yet-flushed here -- convert it to
	 * an error.
	 */
	if ((ret = memp_fsync(dbp->mpf)) == DB_INCOMPLETE)
		ret = EINVAL;

	/* Release the locks. */
	(void)__BT_LPUT(dbp, metalock);
	(void)__BT_LPUT(dbp, rootlock);

	return (ret);
}