1 /* $OpenBSD: bt_put.c,v 1.13 2005/08/05 13:02:59 espie Exp $ */
2
3 /*-
4 * Copyright (c) 1990, 1993, 1994
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Mike Olson.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #include <sys/types.h>
36
37 #include <errno.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41
42 #include <db.h>
43 #include "btree.h"
44
45 static EPG *bt_fast(BTREE *, const DBT *, const DBT *, int *);
46
47 /*
48 * __BT_PUT -- Add a btree item to the tree.
49 *
50 * Parameters:
51 * dbp: pointer to access method
52 * key: key
53 * data: data
54 * flag: R_NOOVERWRITE
55 *
56 * Returns:
57 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key is already in the
58 * tree and R_NOOVERWRITE specified.
59 */
60 int
__bt_put(const DB * dbp,DBT * key,const DBT * data,u_int flags)61 __bt_put(const DB *dbp, DBT *key, const DBT *data, u_int flags)
62 {
63 BTREE *t;
64 DBT tkey, tdata;
65 EPG *e;
66 PAGE *h;
67 indx_t idx, nxtindex;
68 pgno_t pg;
69 u_int32_t nbytes, size32;
70 int dflags, exact, status;
71 char *dest, db[NOVFLSIZE], kb[NOVFLSIZE];
72
73 t = dbp->internal;
74
75 /* Toss any page pinned across calls. */
76 if (t->bt_pinned != NULL) {
77 mpool_put(t->bt_mp, t->bt_pinned, 0);
78 t->bt_pinned = NULL;
79 }
80
81 /* Check for change to a read-only tree. */
82 if (F_ISSET(t, B_RDONLY)) {
83 errno = EPERM;
84 return (RET_ERROR);
85 }
86
87 switch (flags) {
88 case 0:
89 case R_NOOVERWRITE:
90 break;
91 case R_CURSOR:
92 /*
93 * If flags is R_CURSOR, put the cursor. Must already
94 * have started a scan and not have already deleted it.
95 */
96 if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
97 !F_ISSET(&t->bt_cursor,
98 CURS_ACQUIRE | CURS_AFTER | CURS_BEFORE))
99 break;
100 /* FALLTHROUGH */
101 default:
102 errno = EINVAL;
103 return (RET_ERROR);
104 }
105
106 /*
107 * If the key/data pair won't fit on a page, store it on overflow
108 * pages. Only put the key on the overflow page if the pair are
109 * still too big after moving the data to an overflow page.
110 *
111 * XXX
112 * If the insert fails later on, the overflow pages aren't recovered.
113 */
114 dflags = 0;
115 if (key->size + data->size > t->bt_ovflsize) {
116 if (key->size > t->bt_ovflsize) {
117 storekey: if (__ovfl_put(t, key, &pg) == RET_ERROR)
118 return (RET_ERROR);
119 tkey.data = kb;
120 tkey.size = NOVFLSIZE;
121 memmove(kb, &pg, sizeof(pgno_t));
122 size32 = key->size;
123 memmove(kb + sizeof(pgno_t),
124 &size32, sizeof(u_int32_t));
125 dflags |= P_BIGKEY;
126 key = &tkey;
127 }
128 if (key->size + data->size > t->bt_ovflsize) {
129 if (__ovfl_put(t, data, &pg) == RET_ERROR)
130 return (RET_ERROR);
131 tdata.data = db;
132 tdata.size = NOVFLSIZE;
133 memmove(db, &pg, sizeof(pgno_t));
134 size32 = data->size;
135 memmove(db + sizeof(pgno_t),
136 &size32, sizeof(u_int32_t));
137 dflags |= P_BIGDATA;
138 data = &tdata;
139 }
140 if (key->size + data->size > t->bt_ovflsize)
141 goto storekey;
142 }
143
144 /* Replace the cursor. */
145 if (flags == R_CURSOR) {
146 if ((h = mpool_get(t->bt_mp, t->bt_cursor.pg.pgno, 0)) == NULL)
147 return (RET_ERROR);
148 idx = t->bt_cursor.pg.index;
149 goto delete;
150 }
151
152 /*
153 * Find the key to delete, or, the location at which to insert.
154 * Bt_fast and __bt_search both pin the returned page.
155 */
156 if (t->bt_order == NOT || (e = bt_fast(t, key, data, &exact)) == NULL)
157 if ((e = __bt_search(t, key, &exact)) == NULL)
158 return (RET_ERROR);
159 h = e->page;
160 idx = e->index;
161
162 /*
163 * Add the key/data pair to the tree. If an identical key is already
164 * in the tree, and R_NOOVERWRITE is set, an error is returned. If
165 * R_NOOVERWRITE is not set, the key is either added (if duplicates are
166 * permitted) or an error is returned.
167 */
168 switch (flags) {
169 case R_NOOVERWRITE:
170 if (!exact)
171 break;
172 mpool_put(t->bt_mp, h, 0);
173 return (RET_SPECIAL);
174 default:
175 if (!exact || !F_ISSET(t, B_NODUPS))
176 break;
177 /*
178 * !!!
179 * Note, the delete may empty the page, so we need to put a
180 * new entry into the page immediately.
181 */
182 delete: if (__bt_dleaf(t, key, h, idx) == RET_ERROR) {
183 mpool_put(t->bt_mp, h, 0);
184 return (RET_ERROR);
185 }
186 break;
187 }
188
189 /*
190 * If not enough room, or the user has put a ceiling on the number of
191 * keys permitted in the page, split the page. The split code will
192 * insert the key and data and unpin the current page. If inserting
193 * into the offset array, shift the pointers up.
194 */
195 nbytes = NBLEAFDBT(key->size, data->size);
196 if (h->upper - h->lower < nbytes + sizeof(indx_t)) {
197 if ((status = __bt_split(t, h, key,
198 data, dflags, nbytes, idx)) != RET_SUCCESS)
199 return (status);
200 goto success;
201 }
202
203 if (idx < (nxtindex = NEXTINDEX(h)))
204 memmove(h->linp + idx + 1, h->linp + idx,
205 (nxtindex - idx) * sizeof(indx_t));
206 h->lower += sizeof(indx_t);
207
208 h->linp[idx] = h->upper -= nbytes;
209 dest = (char *)h + h->upper;
210 WR_BLEAF(dest, key, data, dflags);
211
212 /* If the cursor is on this page, adjust it as necessary. */
213 if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
214 !F_ISSET(&t->bt_cursor, CURS_ACQUIRE) &&
215 t->bt_cursor.pg.pgno == h->pgno && t->bt_cursor.pg.index >= idx)
216 ++t->bt_cursor.pg.index;
217
218 if (t->bt_order == NOT) {
219 if (h->nextpg == P_INVALID) {
220 if (idx == NEXTINDEX(h) - 1) {
221 t->bt_order = FORWARD;
222 t->bt_last.index = idx;
223 t->bt_last.pgno = h->pgno;
224 }
225 } else if (h->prevpg == P_INVALID) {
226 if (idx == 0) {
227 t->bt_order = BACK;
228 t->bt_last.index = 0;
229 t->bt_last.pgno = h->pgno;
230 }
231 }
232 }
233
234 mpool_put(t->bt_mp, h, MPOOL_DIRTY);
235
236 success:
237 if (flags == R_SETCURSOR)
238 __bt_setcur(t, e->page->pgno, e->index);
239
240 F_SET(t, B_MODIFIED);
241 return (RET_SUCCESS);
242 }
243
244 #ifdef STATISTICS
245 u_long bt_cache_hit, bt_cache_miss;
246 #endif
247
248 /*
249 * BT_FAST -- Do a quick check for sorted data.
250 *
251 * Parameters:
252 * t: tree
253 * key: key to insert
254 *
255 * Returns:
256 * EPG for new record or NULL if not found.
257 */
258 static EPG *
bt_fast(BTREE * t,const DBT * key,const DBT * data,int * exactp)259 bt_fast(BTREE *t, const DBT *key, const DBT *data, int *exactp)
260 {
261 PAGE *h;
262 u_int32_t nbytes;
263 int cmp;
264
265 if ((h = mpool_get(t->bt_mp, t->bt_last.pgno, 0)) == NULL) {
266 t->bt_order = NOT;
267 return (NULL);
268 }
269 t->bt_cur.page = h;
270 t->bt_cur.index = t->bt_last.index;
271
272 /*
273 * If won't fit in this page or have too many keys in this page,
274 * have to search to get split stack.
275 */
276 nbytes = NBLEAFDBT(key->size, data->size);
277 if (h->upper - h->lower < nbytes + sizeof(indx_t))
278 goto miss;
279
280 if (t->bt_order == FORWARD) {
281 if (t->bt_cur.page->nextpg != P_INVALID)
282 goto miss;
283 if (t->bt_cur.index != NEXTINDEX(h) - 1)
284 goto miss;
285 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) < 0)
286 goto miss;
287 t->bt_last.index = cmp ? ++t->bt_cur.index : t->bt_cur.index;
288 } else {
289 if (t->bt_cur.page->prevpg != P_INVALID)
290 goto miss;
291 if (t->bt_cur.index != 0)
292 goto miss;
293 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) > 0)
294 goto miss;
295 t->bt_last.index = 0;
296 }
297 *exactp = cmp == 0;
298 #ifdef STATISTICS
299 ++bt_cache_hit;
300 #endif
301 return (&t->bt_cur);
302
303 miss:
304 #ifdef STATISTICS
305 ++bt_cache_miss;
306 #endif
307 t->bt_order = NOT;
308 mpool_put(t->bt_mp, h, 0);
309 return (NULL);
310 }
311