Asterisk - The Open Source Telephony Project GIT-master-f3e88d3
Functions
bt_split.c File Reference
#include <sys/types.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "../include/db.h"
#include "btree.h"
Include dependency graph for bt_split.c:

Go to the source code of this file.

Functions

int __bt_split (BTREE *t, PAGE *sp, const DBT *key, const DBT *data, int flags, size_t ilen, u_int32_t argskip)
 
static PAGE *bt_page __P ((BTREE *, PAGE *, PAGE **, PAGE **, indx_t *, size_t))
 
static int bt_broot __P ((BTREE *, PAGE *, PAGE *, PAGE *))
 
static PAGE *bt_psplit __P ((BTREE *, PAGE *, PAGE *, PAGE *, indx_t *, size_t))
 
static int bt_preserve __P ((BTREE *, pgno_t))
 
static recno_t rec_total __P ((PAGE *))
 
static int bt_broot (BTREE *t, PAGE *h, PAGE *l, PAGE *r)
 
static PAGEbt_page (BTREE *t, PAGE *h, PAGE **lp, PAGE **rp, indx_t *skip, size_t ilen)
 
static int bt_preserve (BTREE *t, pgno_t pg)
 
static PAGEbt_psplit (BTREE *t, PAGE *h, PAGE *l, PAGE *r, indx_t *pskip, size_t ilen)
 
static PAGEbt_root (BTREE *t, PAGE *h, PAGE **lp, PAGE **rp, indx_t *skip, size_t ilen)
 
static int bt_rroot (BTREE *t, PAGE *h, PAGE *l, PAGE *r)
 
static recno_t rec_total (PAGE *h)
 

Function Documentation

◆ __bt_split()

int __bt_split ( BTREE t,
PAGE sp,
const DBT key,
const DBT data,
int  flags,
size_t  ilen,
u_int32_t  argskip 
)

Definition at line 82 of file bt_split.c.

89{
90 BINTERNAL *bi = 0;
91 BLEAF *bl = 0, *tbl;
92 DBT a, b;
93 EPGNO *parent;
94 PAGE *h, *l, *r, *lchild, *rchild;
95 indx_t nxtindex;
96 u_int16_t skip;
97 u_int32_t n, nbytes, nksize = 0;
98 int parentsplit;
99 char *dest;
100
101 /*
102 * Split the page into two pages, l and r. The split routines return
103 * a pointer to the page into which the key should be inserted and with
104 * skip set to the offset which should be used. Additionally, l and r
105 * are pinned.
106 */
107 skip = argskip;
108 h = sp->pgno == P_ROOT ?
109 bt_root(t, sp, &l, &r, &skip, ilen) :
110 bt_page(t, sp, &l, &r, &skip, ilen);
111 if (h == NULL)
112 return (RET_ERROR);
113
114 /*
115 * Insert the new key/data pair into the leaf page. (Key inserts
116 * always cause a leaf page to split first.)
117 */
118 h->linp[skip] = h->upper -= ilen;
119 dest = (char *)h + h->upper;
120 if (F_ISSET(t, R_RECNO))
121 WR_RLEAF(dest, data, flags)
122 else
123 WR_BLEAF(dest, key, data, flags)
124
125 /* If the root page was split, make it look right. */
126 if (sp->pgno == P_ROOT &&
127 (F_ISSET(t, R_RECNO) ?
128 bt_rroot(t, sp, l, r) : bt_broot(t, sp, l, r)) == RET_ERROR)
129 goto err2;
130
131 /*
132 * Now we walk the parent page stack -- a LIFO stack of the pages that
133 * were traversed when we searched for the page that split. Each stack
134 * entry is a page number and a page index offset. The offset is for
135 * the page traversed on the search. We've just split a page, so we
136 * have to insert a new key into the parent page.
137 *
138 * If the insert into the parent page causes it to split, may have to
139 * continue splitting all the way up the tree. We stop if the root
140 * splits or the page inserted into didn't have to split to hold the
141 * new key. Some algorithms replace the key for the old page as well
142 * as the new page. We don't, as there's no reason to believe that the
143 * first key on the old page is any better than the key we have, and,
144 * in the case of a key being placed at index 0 causing the split, the
145 * key is unavailable.
146 *
147 * There are a maximum of 5 pages pinned at any time. We keep the left
148 * and right pages pinned while working on the parent. The 5 are the
149 * two children, left parent and right parent (when the parent splits)
150 * and the root page or the overflow key page when calling bt_preserve.
151 * This code must make sure that all pins are released other than the
152 * root page or overflow page which is unlocked elsewhere.
153 */
154 while ((parent = BT_POP(t)) != NULL) {
155 lchild = l;
156 rchild = r;
157
158 /* Get the parent page. */
159 if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
160 goto err2;
161
162 /*
163 * The new key goes ONE AFTER the index, because the split
164 * was to the right.
165 */
166 skip = parent->index + 1;
167
168 /*
169 * Calculate the space needed on the parent page.
170 *
171 * Prefix trees: space hack when inserting into BINTERNAL
172 * pages. Retain only what's needed to distinguish between
173 * the new entry and the LAST entry on the page to its left.
174 * If the keys compare equal, retain the entire key. Note,
175 * we don't touch overflow keys, and the entire key must be
176 * retained for the next-to-left most key on the leftmost
177 * page of each level, or the search will fail. Applicable
178 * ONLY to internal pages that have leaf pages as children.
179 * Further reduction of the key between pairs of internal
180 * pages loses too much information.
181 */
182 switch (rchild->flags & P_TYPE) {
183 case P_BINTERNAL:
184 bi = GETBINTERNAL(rchild, 0);
185 nbytes = NBINTERNAL(bi->ksize);
186 break;
187 case P_BLEAF:
188 bl = GETBLEAF(rchild, 0);
189 nbytes = NBINTERNAL(bl->ksize);
190 if (t->bt_pfx && !(bl->flags & P_BIGKEY) &&
191 (h->prevpg != P_INVALID || skip > 1)) {
192 tbl = GETBLEAF(lchild, NEXTINDEX(lchild) - 1);
193 a.size = tbl->ksize;
194 a.data = tbl->bytes;
195 b.size = bl->ksize;
196 b.data = bl->bytes;
197 nksize = t->bt_pfx(&a, &b);
198 n = NBINTERNAL(nksize);
199 if (n < nbytes) {
200#ifdef STATISTICS
201 bt_pfxsaved += nbytes - n;
202#endif
203 nbytes = n;
204 } else
205 nksize = 0;
206 } else
207 nksize = 0;
208 break;
209 case P_RINTERNAL:
210 case P_RLEAF:
211 nbytes = NRINTERNAL;
212 break;
213 default:
214 abort();
215 }
216
217 /* Split the parent page if necessary or shift the indices. */
218 if ((u_int32_t) (h->upper - h->lower)
219 < nbytes + sizeof(indx_t)) {
220 sp = h;
221 h = h->pgno == P_ROOT ?
222 bt_root(t, h, &l, &r, &skip, nbytes) :
223 bt_page(t, h, &l, &r, &skip, nbytes);
224 if (h == NULL)
225 goto err1;
226 parentsplit = 1;
227 } else {
228 if (skip < (nxtindex = NEXTINDEX(h)))
229 memmove(h->linp + skip + 1, h->linp + skip,
230 (nxtindex - skip) * sizeof(indx_t));
231 h->lower += sizeof(indx_t);
232 parentsplit = 0;
233 }
234
235 /* Insert the key into the parent page. */
236 switch (rchild->flags & P_TYPE) {
237 case P_BINTERNAL:
238 h->linp[skip] = h->upper -= nbytes;
239 dest = (char *)h + h->linp[skip];
240 memmove(dest, bi, nbytes);
241 ((BINTERNAL *)dest)->pgno = rchild->pgno;
242 break;
243 case P_BLEAF:
244 h->linp[skip] = h->upper -= nbytes;
245 dest = (char *)h + h->linp[skip];
246 WR_BINTERNAL(dest, nksize ? nksize : bl->ksize,
247 rchild->pgno, bl->flags & P_BIGKEY);
248 memmove(dest, bl->bytes, nksize ? nksize : bl->ksize);
249 if (bl->flags & P_BIGKEY &&
250 bt_preserve(t, *(pgno_t *)bl->bytes) == RET_ERROR)
251 goto err1;
252 break;
253 case P_RINTERNAL:
254 /*
255 * Update the left page count. If split
256 * added at index 0, fix the correct page.
257 */
258 if (skip > 0)
259 dest = (char *)h + h->linp[skip - 1];
260 else
261 dest = (char *)l + l->linp[NEXTINDEX(l) - 1];
262 ((RINTERNAL *)dest)->nrecs = rec_total(lchild);
263 ((RINTERNAL *)dest)->pgno = lchild->pgno;
264
265 /* Update the right page count. */
266 h->linp[skip] = h->upper -= nbytes;
267 dest = (char *)h + h->linp[skip];
268 ((RINTERNAL *)dest)->nrecs = rec_total(rchild);
269 ((RINTERNAL *)dest)->pgno = rchild->pgno;
270 break;
271 case P_RLEAF:
272 /*
273 * Update the left page count. If split
274 * added at index 0, fix the correct page.
275 */
276 if (skip > 0)
277 dest = (char *)h + h->linp[skip - 1];
278 else
279 dest = (char *)l + l->linp[NEXTINDEX(l) - 1];
280 ((RINTERNAL *)dest)->nrecs = NEXTINDEX(lchild);
281 ((RINTERNAL *)dest)->pgno = lchild->pgno;
282
283 /* Update the right page count. */
284 h->linp[skip] = h->upper -= nbytes;
285 dest = (char *)h + h->linp[skip];
286 ((RINTERNAL *)dest)->nrecs = NEXTINDEX(rchild);
287 ((RINTERNAL *)dest)->pgno = rchild->pgno;
288 break;
289 default:
290 abort();
291 }
292
293 /* Unpin the held pages. */
294 if (!parentsplit) {
296 break;
297 }
298
299 /* If the root page was split, make it look right. */
300 if (sp->pgno == P_ROOT &&
301 (F_ISSET(t, R_RECNO) ?
302 bt_rroot(t, sp, l, r) : bt_broot(t, sp, l, r)) == RET_ERROR)
303 goto err1;
304
305 mpool_put(t->bt_mp, lchild, MPOOL_DIRTY);
306 mpool_put(t->bt_mp, rchild, MPOOL_DIRTY);
307 }
308
309 /* Unpin the held pages. */
312
313 /* Clear any pages left on the stack. */
314 return (RET_SUCCESS);
315
316 /*
317 * If something fails in the above loop we were already walking back
318 * up the tree and the tree is now inconsistent. Nothing much we can
319 * do about it but release any memory we're holding.
320 */
321err1: mpool_put(t->bt_mp, lchild, MPOOL_DIRTY);
322 mpool_put(t->bt_mp, rchild, MPOOL_DIRTY);
323
324err2: mpool_put(t->bt_mp, l, 0);
325 mpool_put(t->bt_mp, r, 0);
326 __dbpanic(t->bt_dbp);
327 return (RET_ERROR);
328}
if(!yyg->yy_init)
Definition: ast_expr2f.c:854
static int bt_rroot(BTREE *t, PAGE *h, PAGE *l, PAGE *r)
Definition: bt_split.c:497
static recno_t rec_total(PAGE *h)
Definition: bt_split.c:820
static int bt_broot(BTREE *t, PAGE *h, PAGE *l, PAGE *r)
Definition: bt_split.c:537
static PAGE * bt_page(BTREE *t, PAGE *h, PAGE **lp, PAGE **rp, indx_t *skip, size_t ilen)
Definition: bt_split.c:345
static PAGE * bt_root(BTREE *t, PAGE *h, PAGE **lp, PAGE **rp, indx_t *skip, size_t ilen)
Definition: bt_split.c:450
static int bt_preserve(BTREE *t, pgno_t pg)
Definition: bt_split.c:792
#define WR_BINTERNAL(p, size, pgno, flags)
Definition: btree.h:146
#define F_ISSET(p, f)
Definition: btree.h:42
#define WR_RLEAF(p, data, flags)
Definition: btree.h:231
#define P_RLEAF
Definition: btree.h:84
#define GETBLEAF(pg, indx)
Definition: btree.h:188
#define P_RINTERNAL
Definition: btree.h:83
#define R_RECNO
Definition: btree.h:375
#define NEXTINDEX(p)
Definition: btree.h:98
#define P_TYPE
Definition: btree.h:85
#define WR_BLEAF(p, key, data, flags)
Definition: btree.h:200
#define P_BIGKEY
Definition: btree.h:132
#define GETBINTERNAL(pg, indx)
Definition: btree.h:138
#define P_BINTERNAL
Definition: btree.h:80
#define P_INVALID
Definition: btree.h:63
#define NRINTERNAL
Definition: btree.h:169
#define NBINTERNAL(len)
Definition: btree.h:142
#define BT_POP(t)
Definition: btree.h:327
#define P_BLEAF
Definition: btree.h:81
#define P_ROOT
Definition: btree.h:65
u_int16_t indx_t
Definition: db.h:80
#define RET_SUCCESS
Definition: db.h:52
#define RET_ERROR
Definition: db.h:51
u_int32_t pgno_t
Definition: db.h:78
unsigned int u_int32_t
unsigned short u_int16_t
void * mpool_get(MPOOL *mp, pgno_t pgno, u_int flags)
Definition: mpool.c:165
int mpool_put(MPOOL *mp, void *page, u_int flags)
Definition: mpool.c:251
#define MPOOL_DIRTY
Definition: mpool.h:61
#define NULL
Definition: resample.c:96
Definition: db.h:85
u_int32_t ksize
Definition: btree.h:129
Definition: btree.h:180
u_char flags
Definition: btree.h:183
char bytes[1]
Definition: btree.h:184
u_int32_t ksize
Definition: btree.h:181
MPOOL * bt_mp
Definition: btree.h:313
DB * bt_dbp
Definition: btree.h:315
Definition: btree.h:249
pgno_t pgno
Definition: btree.h:250
indx_t index
Definition: btree.h:251
Definition: btree.h:75
pgno_t prevpg
Definition: btree.h:77
indx_t lower
Definition: btree.h:89
indx_t upper
Definition: btree.h:90
u_int32_t flags
Definition: btree.h:87
pgno_t pgno
Definition: btree.h:76
indx_t linp[1]
Definition: btree.h:91
static struct test_val b
static struct test_val a
void __dbpanic(DB *dbp)

References __dbpanic(), a, b, bt_broot(), _btree::bt_dbp, _btree::bt_mp, bt_page(), BT_POP, bt_preserve(), bt_root(), bt_rroot(), _bleaf::bytes, F_ISSET, _page::flags, _bleaf::flags, GETBINTERNAL, GETBLEAF, if(), _epgno::index, _binternal::ksize, _bleaf::ksize, _page::linp, _page::lower, MPOOL_DIRTY, mpool_get(), mpool_put(), NBINTERNAL, NEXTINDEX, NRINTERNAL, NULL, P_BIGKEY, P_BINTERNAL, P_BLEAF, P_INVALID, P_RINTERNAL, P_RLEAF, P_ROOT, P_TYPE, _page::pgno, _epgno::pgno, _page::prevpg, R_RECNO, rec_total(), RET_ERROR, RET_SUCCESS, _page::upper, WR_BINTERNAL, WR_BLEAF, and WR_RLEAF.

Referenced by __bt_put(), and __rec_iput().

◆ __P() [1/5]

static PAGE *bt_root __P ( (BTREE *, PAGE *, PAGE **, PAGE **, indx_t *, size_t)  )
static

◆ __P() [2/5]

static int bt_rroot __P ( (BTREE *, PAGE *, PAGE *, PAGE *)  )
static

◆ __P() [3/5]

static PAGE *bt_psplit __P ( (BTREE *, PAGE *, PAGE *, PAGE *, indx_t *, size_t)  )
static

◆ __P() [4/5]

static int bt_preserve __P ( (BTREE *, pgno_t )
static

◆ __P() [5/5]

static recno_t rec_total __P ( (PAGE *)  )
static

◆ bt_broot()

static int bt_broot ( BTREE t,
PAGE h,
PAGE l,
PAGE r 
)
static

Definition at line 537 of file bt_split.c.

540{
541 BINTERNAL *bi;
542 BLEAF *bl;
543 u_int32_t nbytes;
544 char *dest;
545
546 /*
547 * If the root page was a leaf page, change it into an internal page.
548 * We copy the key we split on (but not the key's data, in the case of
549 * a leaf page) to the new root page.
550 *
551 * The btree comparison code guarantees that the left-most key on any
552 * level of the tree is never used, so it doesn't need to be filled in.
553 */
554 nbytes = NBINTERNAL(0);
555 h->linp[0] = h->upper = t->bt_psize - nbytes;
556 dest = (char *)h + h->upper;
557 WR_BINTERNAL(dest, 0, l->pgno, 0);
558
559 switch (h->flags & P_TYPE) {
560 case P_BLEAF:
561 bl = GETBLEAF(r, 0);
562 nbytes = NBINTERNAL(bl->ksize);
563 h->linp[1] = h->upper -= nbytes;
564 dest = (char *)h + h->upper;
565 WR_BINTERNAL(dest, bl->ksize, r->pgno, 0);
566 memmove(dest, bl->bytes, bl->ksize);
567
568 /*
569 * If the key is on an overflow page, mark the overflow chain
570 * so it isn't deleted when the leaf copy of the key is deleted.
571 */
572 if (bl->flags & P_BIGKEY &&
573 bt_preserve(t, *(pgno_t *)bl->bytes) == RET_ERROR)
574 return (RET_ERROR);
575 break;
576 case P_BINTERNAL:
577 bi = GETBINTERNAL(r, 0);
578 nbytes = NBINTERNAL(bi->ksize);
579 h->linp[1] = h->upper -= nbytes;
580 dest = (char *)h + h->upper;
581 memmove(dest, bi, nbytes);
582 ((BINTERNAL *)dest)->pgno = r->pgno;
583 break;
584 default:
585 abort();
586 }
587
588 /* There are two keys on the page. */
589 h->lower = BTDATAOFF + 2 * sizeof(indx_t);
590
591 /* Unpin the root page, set to btree internal page. */
592 h->flags &= ~P_TYPE;
593 h->flags |= P_BINTERNAL;
595
596 return (RET_SUCCESS);
597}
#define BTDATAOFF
Definition: btree.h:95
u_int32_t bt_psize
Definition: btree.h:338

References _btree::bt_mp, bt_preserve(), _btree::bt_psize, BTDATAOFF, _bleaf::bytes, _page::flags, _bleaf::flags, GETBINTERNAL, GETBLEAF, _binternal::ksize, _bleaf::ksize, _page::linp, _page::lower, MPOOL_DIRTY, mpool_put(), NBINTERNAL, P_BIGKEY, P_BINTERNAL, P_BLEAF, P_TYPE, _page::pgno, RET_ERROR, RET_SUCCESS, _page::upper, and WR_BINTERNAL.

Referenced by __bt_split().

◆ bt_page()

static PAGE * bt_page ( BTREE t,
PAGE h,
PAGE **  lp,
PAGE **  rp,
indx_t skip,
size_t  ilen 
)
static

Definition at line 345 of file bt_split.c.

350{
351 PAGE *l, *r, *tp;
352 pgno_t npg;
353
354#ifdef STATISTICS
355 ++bt_split;
356#endif
357 /* Put the new right page for the split into place. */
358 if ((r = __bt_new(t, &npg)) == NULL)
359 return (NULL);
360 r->pgno = npg;
361 r->lower = BTDATAOFF;
362 r->upper = t->bt_psize;
363 r->nextpg = h->nextpg;
364 r->prevpg = h->pgno;
365 r->flags = h->flags & P_TYPE;
366
367 /*
368 * If we're splitting the last page on a level because we're appending
369 * a key to it (skip is NEXTINDEX()), it's likely that the data is
370 * sorted. Adding an empty page on the side of the level is less work
371 * and can push the fill factor much higher than normal. If we're
372 * wrong it's no big deal, we'll just do the split the right way next
373 * time. It may look like it's equally easy to do a similar hack for
374 * reverse sorted data, that is, split the tree left, but it's not.
375 * Don't even try.
376 */
377 if (h->nextpg == P_INVALID && *skip == NEXTINDEX(h)) {
378#ifdef STATISTICS
379 ++bt_sortsplit;
380#endif
381 h->nextpg = r->pgno;
382 r->lower = BTDATAOFF + sizeof(indx_t);
383 *skip = 0;
384 *lp = h;
385 *rp = r;
386 return (r);
387 }
388
389 /* Put the new left page for the split into place. */
390 if ((l = (PAGE *)malloc(t->bt_psize)) == NULL) {
391 mpool_put(t->bt_mp, r, 0);
392 return (NULL);
393 }
394#ifdef PURIFY
395 memset(l, 0xff, t->bt_psize);
396#endif
397 l->pgno = h->pgno;
398 l->nextpg = r->pgno;
399 l->prevpg = h->prevpg;
400 l->lower = BTDATAOFF;
401 l->upper = t->bt_psize;
402 l->flags = h->flags & P_TYPE;
403
404 /* Fix up the previous pointer of the page after the split page. */
405 if (h->nextpg != P_INVALID) {
406 if ((tp = mpool_get(t->bt_mp, h->nextpg, 0)) == NULL) {
407 free(l);
408 /* XXX mpool_free(t->bt_mp, r->pgno); */
409 return (NULL);
410 }
411 tp->prevpg = r->pgno;
412 mpool_put(t->bt_mp, tp, MPOOL_DIRTY);
413 }
414
415 /*
416 * Split right. The key/data pairs aren't sorted in the btree page so
417 * it's simpler to copy the data from the split page onto two new pages
418 * instead of copying half the data to the right page and compacting
419 * the left page in place. Since the left page can't change, we have
420 * to swap the original and the allocated left page after the split.
421 */
422 tp = bt_psplit(t, h, l, r, skip, ilen);
423
424 /* Move the new left page onto the old left page. */
425 memmove(h, l, t->bt_psize);
426 if (tp == l)
427 tp = h;
428 free(l);
429
430 *lp = h;
431 *rp = r;
432 return (tp);
433}
PAGE * __bt_new(BTREE *t, pgno_t *npg)
Definition: bt_page.c:86
static PAGE * bt_psplit(BTREE *t, PAGE *h, PAGE *l, PAGE *r, indx_t *pskip, size_t ilen)
Definition: bt_split.c:614
char * malloc()
void free()
pgno_t nextpg
Definition: btree.h:78

References __bt_new(), _btree::bt_mp, _btree::bt_psize, bt_psplit(), BTDATAOFF, _page::flags, free(), _page::lower, malloc(), MPOOL_DIRTY, mpool_get(), mpool_put(), NEXTINDEX, _page::nextpg, NULL, P_INVALID, P_TYPE, _page::pgno, _page::prevpg, and _page::upper.

Referenced by __bt_split().

◆ bt_preserve()

static int bt_preserve ( BTREE t,
pgno_t  pg 
)
static

Definition at line 792 of file bt_split.c.

795{
796 PAGE *h;
797
798 if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
799 return (RET_ERROR);
800 h->flags |= P_PRESERVE;
802 return (RET_SUCCESS);
803}
#define P_PRESERVE
Definition: btree.h:86

References _btree::bt_mp, _page::flags, MPOOL_DIRTY, mpool_get(), mpool_put(), NULL, P_PRESERVE, RET_ERROR, and RET_SUCCESS.

Referenced by __bt_split(), and bt_broot().

◆ bt_psplit()

static PAGE * bt_psplit ( BTREE t,
PAGE h,
PAGE l,
PAGE r,
indx_t pskip,
size_t  ilen 
)
static

Definition at line 614 of file bt_split.c.

619{
620 BINTERNAL *bi;
621 BLEAF *bl;
622 CURSOR *c;
623 RLEAF *rl;
624 PAGE *rval;
625 void *src = 0;
626 indx_t full, half, nxt, off, skip, top, used;
627 u_int32_t nbytes;
628 int bigkeycnt, isbigkey;
629
630 /*
631 * Split the data to the left and right pages. Leave the skip index
632 * open. Additionally, make some effort not to split on an overflow
633 * key. This makes internal page processing faster and can save
634 * space as overflow keys used by internal pages are never deleted.
635 */
636 bigkeycnt = 0;
637 skip = *pskip;
638 full = t->bt_psize - BTDATAOFF;
639 half = full / 2;
640 used = 0;
641 for (nxt = off = 0, top = NEXTINDEX(h); nxt < top; ++off) {
642 if (skip == off) {
643 nbytes = ilen;
644 isbigkey = 0; /* XXX: not really known. */
645 } else
646 switch (h->flags & P_TYPE) {
647 case P_BINTERNAL:
648 src = bi = GETBINTERNAL(h, nxt);
649 nbytes = NBINTERNAL(bi->ksize);
650 isbigkey = bi->flags & P_BIGKEY;
651 break;
652 case P_BLEAF:
653 src = bl = GETBLEAF(h, nxt);
654 nbytes = NBLEAF(bl);
655 isbigkey = bl->flags & P_BIGKEY;
656 break;
657 case P_RINTERNAL:
658 src = GETRINTERNAL(h, nxt);
659 nbytes = NRINTERNAL;
660 isbigkey = 0;
661 break;
662 case P_RLEAF:
663 src = rl = GETRLEAF(h, nxt);
664 nbytes = NRLEAF(rl);
665 isbigkey = 0;
666 break;
667 default:
668 abort();
669 }
670
671 /*
672 * If the key/data pairs are substantial fractions of the max
673 * possible size for the page, it's possible to get situations
674 * where we decide to try and copy too much onto the left page.
675 * Make sure that doesn't happen.
676 */
677 if ((skip <= off && used + nbytes + sizeof(indx_t) >= full)
678 || nxt == top - 1) {
679 --off;
680 break;
681 }
682
683 /* Copy the key/data pair, if not the skipped index. */
684 if (skip != off) {
685 ++nxt;
686
687 l->linp[off] = l->upper -= nbytes;
688 memmove((char *)l + l->upper, src, nbytes);
689 }
690
691 used += nbytes + sizeof(indx_t);
692 if (used >= half) {
693 if (!isbigkey || bigkeycnt == 3)
694 break;
695 else
696 ++bigkeycnt;
697 }
698 }
699
700 /*
701 * Off is the last offset that's valid for the left page.
702 * Nxt is the first offset to be placed on the right page.
703 */
704 l->lower += (off + 1) * sizeof(indx_t);
705
706 /*
707 * If splitting the page that the cursor was on, the cursor has to be
708 * adjusted to point to the same record as before the split. If the
709 * cursor is at or past the skipped slot, the cursor is incremented by
710 * one. If the cursor is on the right page, it is decremented by the
711 * number of records split to the left page.
712 */
713 c = &t->bt_cursor;
714 if (F_ISSET(c, CURS_INIT) && c->pg.pgno == h->pgno) {
715 if (c->pg.index >= skip)
716 ++c->pg.index;
717 if (c->pg.index < nxt) /* Left page. */
718 c->pg.pgno = l->pgno;
719 else { /* Right page. */
720 c->pg.pgno = r->pgno;
721 c->pg.index -= nxt;
722 }
723 }
724
725 /*
726 * If the skipped index was on the left page, just return that page.
727 * Otherwise, adjust the skip index to reflect the new position on
728 * the right page.
729 */
730 if (skip <= off) {
731 skip = 0;
732 rval = l;
733 } else {
734 rval = r;
735 *pskip -= nxt;
736 }
737
738 for (off = 0; nxt < top; ++off) {
739 if (skip == nxt) {
740 ++off;
741 skip = 0;
742 }
743 switch (h->flags & P_TYPE) {
744 case P_BINTERNAL:
745 src = bi = GETBINTERNAL(h, nxt);
746 nbytes = NBINTERNAL(bi->ksize);
747 break;
748 case P_BLEAF:
749 src = bl = GETBLEAF(h, nxt);
750 nbytes = NBLEAF(bl);
751 break;
752 case P_RINTERNAL:
753 src = GETRINTERNAL(h, nxt);
754 nbytes = NRINTERNAL;
755 break;
756 case P_RLEAF:
757 src = rl = GETRLEAF(h, nxt);
758 nbytes = NRLEAF(rl);
759 break;
760 default:
761 abort();
762 }
763 ++nxt;
764 r->linp[off] = r->upper -= nbytes;
765 memmove((char *)r + r->upper, src, nbytes);
766 }
767 r->lower += off * sizeof(indx_t);
768
769 /* If the key is being appended to the page, adjust the index. */
770 if (skip == top)
771 r->lower += sizeof(indx_t);
772
773 return (rval);
774}
#define NRLEAF(p)
Definition: btree.h:224
#define NBLEAF(p)
Definition: btree.h:192
#define GETRINTERNAL(pg, indx)
Definition: btree.h:165
#define CURS_INIT
Definition: btree.h:291
#define GETRLEAF(pg, indx)
Definition: btree.h:220
u_char flags
Definition: btree.h:133
CURSOR bt_cursor
Definition: btree.h:320
Definition: btree.h:283
Definition: btree.h:213
static struct test_val c

References _btree::bt_cursor, _btree::bt_psize, BTDATAOFF, c, CURS_INIT, F_ISSET, _page::flags, _binternal::flags, _bleaf::flags, GETBINTERNAL, GETBLEAF, GETRINTERNAL, GETRLEAF, _binternal::ksize, _page::linp, _page::lower, NBINTERNAL, NBLEAF, NEXTINDEX, NRINTERNAL, NRLEAF, P_BIGKEY, P_BINTERNAL, P_BLEAF, P_RINTERNAL, P_RLEAF, P_TYPE, _page::pgno, and _page::upper.

Referenced by bt_page(), and bt_root().

◆ bt_root()

static PAGE * bt_root ( BTREE t,
PAGE h,
PAGE **  lp,
PAGE **  rp,
indx_t skip,
size_t  ilen 
)
static

Definition at line 450 of file bt_split.c.

455{
456 PAGE *l, *r, *tp;
457 pgno_t lnpg, rnpg;
458
459#ifdef STATISTICS
460 ++bt_split;
461 ++bt_rootsplit;
462#endif
463 /* Put the new left and right pages for the split into place. */
464 if ((l = __bt_new(t, &lnpg)) == NULL ||
465 (r = __bt_new(t, &rnpg)) == NULL)
466 return (NULL);
467 l->pgno = lnpg;
468 r->pgno = rnpg;
469 l->nextpg = r->pgno;
470 r->prevpg = l->pgno;
471 l->prevpg = r->nextpg = P_INVALID;
472 l->lower = r->lower = BTDATAOFF;
473 l->upper = r->upper = t->bt_psize;
474 l->flags = r->flags = h->flags & P_TYPE;
475
476 /* Split the root page. */
477 tp = bt_psplit(t, h, l, r, skip, ilen);
478
479 *lp = l;
480 *rp = r;
481 return (tp);
482}

References __bt_new(), _btree::bt_psize, bt_psplit(), BTDATAOFF, _page::flags, _page::lower, _page::nextpg, NULL, P_INVALID, P_TYPE, _page::pgno, _page::prevpg, and _page::upper.

Referenced by __bt_split().

◆ bt_rroot()

static int bt_rroot ( BTREE t,
PAGE h,
PAGE l,
PAGE r 
)
static

Definition at line 497 of file bt_split.c.

500{
501 char *dest;
502
503 /* Insert the left and right keys, set the header information. */
504 h->linp[0] = h->upper = t->bt_psize - NRINTERNAL;
505 dest = (char *)h + h->upper;
506 WR_RINTERNAL(dest,
507 l->flags & P_RLEAF ? NEXTINDEX(l) : rec_total(l), l->pgno);
508
509 h->linp[1] = h->upper -= NRINTERNAL;
510 dest = (char *)h + h->upper;
511 WR_RINTERNAL(dest,
512 r->flags & P_RLEAF ? NEXTINDEX(r) : rec_total(r), r->pgno);
513
514 h->lower = BTDATAOFF + 2 * sizeof(indx_t);
515
516 /* Unpin the root page, set to recno internal page. */
517 h->flags &= ~P_TYPE;
518 h->flags |= P_RINTERNAL;
520
521 return (RET_SUCCESS);
522}
#define WR_RINTERNAL(p, nrecs, pgno)
Definition: btree.h:173

References _btree::bt_mp, _btree::bt_psize, BTDATAOFF, _page::flags, _page::linp, _page::lower, MPOOL_DIRTY, mpool_put(), NEXTINDEX, NRINTERNAL, P_RINTERNAL, P_RLEAF, _page::pgno, rec_total(), RET_SUCCESS, _page::upper, and WR_RINTERNAL.

Referenced by __bt_split().

◆ rec_total()

static recno_t rec_total ( PAGE h)
static

Definition at line 820 of file bt_split.c.

822{
823 recno_t recs;
824 indx_t nxt, top;
825
826 for (recs = 0, nxt = 0, top = NEXTINDEX(h); nxt < top; ++nxt)
827 recs += GETRINTERNAL(h, nxt)->nrecs;
828 return (recs);
829}
u_int32_t recno_t
Definition: db.h:82

References GETRINTERNAL, and NEXTINDEX.

Referenced by __bt_split(), and bt_rroot().