1 /*-
2 * See the file LICENSE for redistribution information.
3 *
4 * Copyright (c) 1996, 1997, 1998
5 * Sleepycat Software. All rights reserved.
6 */
7 /*
8 * Copyright (c) 1990, 1993, 1994, 1995, 1996
9 * Keith Bostic. All rights reserved.
10 */
11 /*
12 * Copyright (c) 1990, 1993, 1994, 1995
13 * The Regents of the University of California. All rights reserved.
14 *
15 * This code is derived from software contributed to Berkeley by
16 * Mike Olson.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 * notice, this list of conditions and the following disclaimer in the
25 * documentation and/or other materials provided with the distribution.
26 * 3. All advertising materials mentioning features or use of this software
27 * must display the following acknowledgement:
28 * This product includes software developed by the University of
29 * California, Berkeley and its contributors.
30 * 4. Neither the name of the University nor the names of its contributors
31 * may be used to endorse or promote products derived from this software
32 * without specific prior written permission.
33 *
34 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
35 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
36 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
37 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
38 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
39 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
40 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
41 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
42 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
43 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
44 * SUCH DAMAGE.
45 */
46
47 #include "config.h"
48
49 #ifndef lint
50 static const char sccsid[] = "@(#)db_overflow.c 10.21 (Sleepycat) 9/27/98";
51 #endif /* not lint */
52
53 #ifndef NO_SYSTEM_INCLUDES
54 #include <sys/types.h>
55
56 #include <errno.h>
57 #include <string.h>
58 #endif
59
60 #include "db_int.h"
61 #include "db_page.h"
62 #include "db_am.h"
63 #include "common_ext.h"
64
65 /*
66 * Big key/data code.
67 *
68 * Big key and data entries are stored on linked lists of pages. The initial
69 * reference is a structure with the total length of the item and the page
70 * number where it begins. Each entry in the linked list contains a pointer
71 * to the next page of data, and so on.
72 */
73
74 /*
75 * __db_goff --
76 * Get an offpage item.
77 *
78 * PUBLIC: int __db_goff __P((DB *, DBT *,
79 * PUBLIC: u_int32_t, db_pgno_t, void **, u_int32_t *));
80 */
81 int
__db_goff(dbp,dbt,tlen,pgno,bpp,bpsz)82 __db_goff(dbp, dbt, tlen, pgno, bpp, bpsz)
83 DB *dbp;
84 DBT *dbt;
85 u_int32_t tlen;
86 db_pgno_t pgno;
87 void **bpp;
88 u_int32_t *bpsz;
89 {
90 PAGE *h;
91 db_indx_t bytes;
92 u_int32_t curoff, needed, start;
93 u_int8_t *p, *src;
94 int ret;
95
96 /*
97 * Check if the buffer is big enough; if it is not and we are
98 * allowed to malloc space, then we'll malloc it. If we are
99 * not (DB_DBT_USERMEM), then we'll set the dbt and return
100 * appropriately.
101 */
102 if (F_ISSET(dbt, DB_DBT_PARTIAL)) {
103 start = dbt->doff;
104 needed = dbt->dlen;
105 } else {
106 start = 0;
107 needed = tlen;
108 }
109
110 /* Allocate any necessary memory. */
111 if (F_ISSET(dbt, DB_DBT_USERMEM)) {
112 if (needed > dbt->ulen) {
113 dbt->size = needed;
114 return (ENOMEM);
115 }
116 } else if (F_ISSET(dbt, DB_DBT_MALLOC)) {
117 if ((ret =
118 __os_malloc(needed, dbp->db_malloc, &dbt->data)) != 0)
119 return (ret);
120 } else if (*bpsz == 0 || *bpsz < needed) {
121 if ((ret = __os_realloc(bpp, needed)) != 0)
122 return (ret);
123 *bpsz = needed;
124 dbt->data = *bpp;
125 } else
126 dbt->data = *bpp;
127
128 /*
129 * Step through the linked list of pages, copying the data on each
130 * one into the buffer. Never copy more than the total data length.
131 */
132 dbt->size = needed;
133 for (curoff = 0, p = dbt->data; pgno != P_INVALID && needed > 0;) {
134 if ((ret = memp_fget(dbp->mpf, &pgno, 0, &h)) != 0) {
135 (void)__db_pgerr(dbp, pgno);
136 return (ret);
137 }
138 /* Check if we need any bytes from this page. */
139 if (curoff + OV_LEN(h) >= start) {
140 src = (u_int8_t *)h + P_OVERHEAD;
141 bytes = OV_LEN(h);
142 if (start > curoff) {
143 src += start - curoff;
144 bytes -= start - curoff;
145 }
146 if (bytes > needed)
147 bytes = needed;
148 memcpy(p, src, bytes);
149 p += bytes;
150 needed -= bytes;
151 }
152 curoff += OV_LEN(h);
153 pgno = h->next_pgno;
154 memp_fput(dbp->mpf, h, 0);
155 }
156 return (0);
157 }
158
159 /*
160 * __db_poff --
161 * Put an offpage item.
162 *
163 * PUBLIC: int __db_poff __P((DBC *, const DBT *, db_pgno_t *,
164 * PUBLIC: int (*)(DBC *, u_int32_t, PAGE **)));
165 */
166 int
__db_poff(dbc,dbt,pgnop,newfunc)167 __db_poff(dbc, dbt, pgnop, newfunc)
168 DBC *dbc;
169 const DBT *dbt;
170 db_pgno_t *pgnop;
171 int (*newfunc) __P((DBC *, u_int32_t, PAGE **));
172 {
173 DB *dbp;
174 PAGE *pagep, *lastp;
175 DB_LSN new_lsn, null_lsn;
176 DBT tmp_dbt;
177 db_indx_t pagespace;
178 u_int32_t sz;
179 u_int8_t *p;
180 int ret;
181
182 /*
183 * Allocate pages and copy the key/data item into them. Calculate the
184 * number of bytes we get for pages we fill completely with a single
185 * item.
186 */
187 dbp = dbc->dbp;
188 pagespace = P_MAXSPACE(dbp->pgsize);
189
190 lastp = NULL;
191 for (p = dbt->data,
192 sz = dbt->size; sz > 0; p += pagespace, sz -= pagespace) {
193 /*
194 * Reduce pagespace so we terminate the loop correctly and
195 * don't copy too much data.
196 */
197 if (sz < pagespace)
198 pagespace = sz;
199
200 /*
201 * Allocate and initialize a new page and copy all or part of
202 * the item onto the page. If sz is less than pagespace, we
203 * have a partial record.
204 */
205 if ((ret = newfunc(dbc, P_OVERFLOW, &pagep)) != 0)
206 return (ret);
207 if (DB_LOGGING(dbc)) {
208 tmp_dbt.data = p;
209 tmp_dbt.size = pagespace;
210 ZERO_LSN(null_lsn);
211 if ((ret = __db_big_log(dbp->dbenv->lg_info, dbc->txn,
212 &new_lsn, 0, DB_ADD_BIG, dbp->log_fileid,
213 PGNO(pagep), lastp ? PGNO(lastp) : PGNO_INVALID,
214 PGNO_INVALID, &tmp_dbt, &LSN(pagep),
215 lastp == NULL ? &null_lsn : &LSN(lastp),
216 &null_lsn)) != 0)
217 return (ret);
218
219 /* Move lsn onto page. */
220 if (lastp)
221 LSN(lastp) = new_lsn;
222 LSN(pagep) = new_lsn;
223 }
224
225 P_INIT(pagep, dbp->pgsize,
226 PGNO(pagep), PGNO_INVALID, PGNO_INVALID, 0, P_OVERFLOW);
227 OV_LEN(pagep) = pagespace;
228 OV_REF(pagep) = 1;
229 memcpy((u_int8_t *)pagep + P_OVERHEAD, p, pagespace);
230
231 /*
232 * If this is the first entry, update the user's info.
233 * Otherwise, update the entry on the last page filled
234 * in and release that page.
235 */
236 if (lastp == NULL)
237 *pgnop = PGNO(pagep);
238 else {
239 lastp->next_pgno = PGNO(pagep);
240 pagep->prev_pgno = PGNO(lastp);
241 (void)memp_fput(dbp->mpf, lastp, DB_MPOOL_DIRTY);
242 }
243 lastp = pagep;
244 }
245 (void)memp_fput(dbp->mpf, lastp, DB_MPOOL_DIRTY);
246 return (0);
247 }
248
249 /*
250 * __db_ovref --
251 * Increment/decrement the reference count on an overflow page.
252 *
253 * PUBLIC: int __db_ovref __P((DBC *, db_pgno_t, int32_t));
254 */
255 int
__db_ovref(dbc,pgno,adjust)256 __db_ovref(dbc, pgno, adjust)
257 DBC *dbc;
258 db_pgno_t pgno;
259 int32_t adjust;
260 {
261 DB *dbp;
262 PAGE *h;
263 int ret;
264
265 dbp = dbc->dbp;
266 if ((ret = memp_fget(dbp->mpf, &pgno, 0, &h)) != 0) {
267 (void)__db_pgerr(dbp, pgno);
268 return (ret);
269 }
270
271 if (DB_LOGGING(dbc))
272 if ((ret = __db_ovref_log(dbp->dbenv->lg_info, dbc->txn,
273 &LSN(h), 0, dbp->log_fileid, h->pgno, adjust,
274 &LSN(h))) != 0)
275 return (ret);
276 OV_REF(h) += adjust;
277
278 (void)memp_fput(dbp->mpf, h, DB_MPOOL_DIRTY);
279 return (0);
280 }
281
282 /*
283 * __db_doff --
284 * Delete an offpage chain of overflow pages.
285 *
286 * PUBLIC: int __db_doff __P((DBC *, db_pgno_t, int (*)(DBC *, PAGE *)));
287 */
288 int
__db_doff(dbc,pgno,freefunc)289 __db_doff(dbc, pgno, freefunc)
290 DBC *dbc;
291 db_pgno_t pgno;
292 int (*freefunc) __P((DBC *, PAGE *));
293 {
294 DB *dbp;
295 PAGE *pagep;
296 DB_LSN null_lsn;
297 DBT tmp_dbt;
298 int ret;
299
300 dbp = dbc->dbp;
301 do {
302 if ((ret = memp_fget(dbp->mpf, &pgno, 0, &pagep)) != 0) {
303 (void)__db_pgerr(dbp, pgno);
304 return (ret);
305 }
306
307 /*
308 * If it's an overflow page and it's referenced by more than
309 * one key/data item, decrement the reference count and return.
310 */
311 if (TYPE(pagep) == P_OVERFLOW && OV_REF(pagep) > 1) {
312 (void)memp_fput(dbp->mpf, pagep, 0);
313 return (__db_ovref(dbc, pgno, -1));
314 }
315
316 if (DB_LOGGING(dbc)) {
317 tmp_dbt.data = (u_int8_t *)pagep + P_OVERHEAD;
318 tmp_dbt.size = OV_LEN(pagep);
319 ZERO_LSN(null_lsn);
320 if ((ret = __db_big_log(dbp->dbenv->lg_info, dbc->txn,
321 &LSN(pagep), 0, DB_REM_BIG, dbp->log_fileid,
322 PGNO(pagep), PREV_PGNO(pagep), NEXT_PGNO(pagep),
323 &tmp_dbt, &LSN(pagep), &null_lsn, &null_lsn)) != 0)
324 return (ret);
325 }
326 pgno = pagep->next_pgno;
327 if ((ret = freefunc(dbc, pagep)) != 0)
328 return (ret);
329 } while (pgno != PGNO_INVALID);
330
331 return (0);
332 }
333
334 /*
335 * __db_moff --
336 * Match on overflow pages.
337 *
338 * Given a starting page number and a key, return <0, 0, >0 to indicate if the
339 * key on the page is less than, equal to or greater than the key specified.
340 * We optimize this by doing chunk at a time comparison unless the user has
341 * specified a comparison function. In this case, we need to materialize
342 * the entire object and call their comparison routine.
343 *
344 * PUBLIC: int __db_moff __P((DB *, const DBT *, db_pgno_t, u_int32_t,
345 * PUBLIC: int (*)(const DBT *, const DBT *), int *));
346 */
347 int
__db_moff(dbp,dbt,pgno,tlen,cmpfunc,cmpp)348 __db_moff(dbp, dbt, pgno, tlen, cmpfunc, cmpp)
349 DB *dbp;
350 const DBT *dbt;
351 db_pgno_t pgno;
352 u_int32_t tlen;
353 int (*cmpfunc) __P((const DBT *, const DBT *)), *cmpp;
354 {
355 PAGE *pagep;
356 DBT local_dbt;
357 void *buf;
358 u_int32_t bufsize, cmp_bytes, key_left;
359 u_int8_t *p1, *p2;
360 int ret;
361
362 /*
363 * If there is a user-specified comparison function, build a
364 * contiguous copy of the key, and call it.
365 */
366 if (cmpfunc != NULL) {
367 memset(&local_dbt, 0, sizeof(local_dbt));
368 buf = NULL;
369 bufsize = 0;
370
371 if ((ret = __db_goff(dbp,
372 &local_dbt, tlen, pgno, &buf, &bufsize)) != 0)
373 return (ret);
374 *cmpp = cmpfunc(&local_dbt, dbt);
375 __os_free(buf, bufsize);
376 return (0);
377 }
378
379 /* While there are both keys to compare. */
380 for (*cmpp = 0, p1 = dbt->data,
381 key_left = dbt->size; key_left > 0 && pgno != PGNO_INVALID;) {
382 if ((ret = memp_fget(dbp->mpf, &pgno, 0, &pagep)) != 0)
383 return (ret);
384
385 cmp_bytes = OV_LEN(pagep) < key_left ? OV_LEN(pagep) : key_left;
386 key_left -= cmp_bytes;
387 for (p2 =
388 (u_int8_t *)pagep + P_OVERHEAD; cmp_bytes-- > 0; ++p1, ++p2)
389 if (*p1 != *p2) {
390 *cmpp = (long)*p1 - (long)*p2;
391 break;
392 }
393 pgno = NEXT_PGNO(pagep);
394 if ((ret = memp_fput(dbp->mpf, pagep, 0)) != 0)
395 return (ret);
396 if (*cmpp != 0)
397 return (0);
398 }
399 if (key_left > 0) /* DBT is longer than page key. */
400 *cmpp = -1;
401 else if (pgno != PGNO_INVALID) /* DBT is shorter than page key. */
402 *cmpp = 1;
403 else
404 *cmpp = 0;
405
406 return (0);
407 }
408