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 int bt_broot	__P ((BTREE *, PAGE *, PAGE *, PAGE *))
static PAGE *bt_page	__P ((BTREE *, PAGE *, PAGE **, PAGE **, indx_t *, size_t))
static int bt_preserve	__P ((BTREE *, pgno_t))
static PAGE *bt_psplit	__P ((BTREE *, PAGE *, PAGE *, PAGE *, indx_t *, size_t))
static recno_t rec_total	__P ((PAGE *))
static int	bt_broot (BTREE *t, PAGE *h, PAGE *l, PAGE *r)
static PAGE *	bt_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 PAGE *	bt_psplit (BTREE *t, PAGE *h, PAGE *l, PAGE *r, indx_t *pskip, size_t ilen)
static PAGE *	bt_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.

References __dbpanic(), a, b, bt_broot(), _btree::bt_dbp, _btree::bt_mp, bt_page(), BT_POP, bt_preserve(), bt_root(), bt_rroot(), _bleaf::bytes, DBT::data, 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, DBT::size, _page::upper, WR_BINTERNAL, WR_BLEAF, and WR_RLEAF.

Referenced by __bt_put(), and __rec_iput().

{
 BINTERNAL *bi = 0;
 BLEAF *bl = 0, *tbl;
 DBT a, b;
 EPGNO *parent;
 PAGE *h, *l, *r, *lchild, *rchild;
 indx_t nxtindex;
 u_int16_t skip;
 u_int32_t n, nbytes, nksize = 0;
 int parentsplit;
 char *dest;

 /*
 * Split the page into two pages, l and r. The split routines return
 * a pointer to the page into which the key should be inserted and with
 * skip set to the offset which should be used. Additionally, l and r
 * are pinned.
 */
 skip = argskip;
 h = sp->pgno == P_ROOT ?
 bt_root(t, sp, &l, &r, &skip, ilen) :
 bt_page(t, sp, &l, &r, &skip, ilen);
 if (h == NULL)
 return (RET_ERROR);

 /*
 * Insert the new key/data pair into the leaf page. (Key inserts
 * always cause a leaf page to split first.)
 */
 h->linp[skip] = h->upper -= ilen;
 dest = (char *)h + h->upper;
 if (F_ISSET(t, R_RECNO))
 WR_RLEAF(dest, data, flags)
 else
 WR_BLEAF(dest, key, data, flags)

 /* If the root page was split, make it look right. */
 if (sp->pgno == P_ROOT &&
 (F_ISSET(t, R_RECNO) ?
 bt_rroot(t, sp, l, r) : bt_broot(t, sp, l, r)) == RET_ERROR)
 goto err2;

 /*
 * Now we walk the parent page stack -- a LIFO stack of the pages that
 * were traversed when we searched for the page that split. Each stack
 * entry is a page number and a page index offset. The offset is for
 * the page traversed on the search. We've just split a page, so we
 * have to insert a new key into the parent page.
 *
 * If the insert into the parent page causes it to split, may have to
 * continue splitting all the way up the tree. We stop if the root
 * splits or the page inserted into didn't have to split to hold the
 * new key. Some algorithms replace the key for the old page as well
 * as the new page. We don't, as there's no reason to believe that the
 * first key on the old page is any better than the key we have, and,
 * in the case of a key being placed at index 0 causing the split, the
 * key is unavailable.
 *
 * There are a maximum of 5 pages pinned at any time. We keep the left
 * and right pages pinned while working on the parent. The 5 are the
 * two children, left parent and right parent (when the parent splits)
 * and the root page or the overflow key page when calling bt_preserve.
 * This code must make sure that all pins are released other than the
 * root page or overflow page which is unlocked elsewhere.
 */
 while ((parent = BT_POP(t)) != NULL) {
 lchild = l;
 rchild = r;

 /* Get the parent page. */
 if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
 goto err2;

 /*
 * The new key goes ONE AFTER the index, because the split
 * was to the right.
 */
 skip = parent->index + 1;

 /*
 * Calculate the space needed on the parent page.
 *
 * Prefix trees: space hack when inserting into BINTERNAL
 * pages. Retain only what's needed to distinguish between
 * the new entry and the LAST entry on the page to its left.
 * If the keys compare equal, retain the entire key. Note,
 * we don't touch overflow keys, and the entire key must be
 * retained for the next-to-left most key on the leftmost
 * page of each level, or the search will fail. Applicable
 * ONLY to internal pages that have leaf pages as children.
 * Further reduction of the key between pairs of internal
 * pages loses too much information.
 */
 switch (rchild->flags & P_TYPE) {
 case P_BINTERNAL:
 bi = GETBINTERNAL(rchild, 0);
 nbytes = NBINTERNAL(bi->ksize);
 break;
 case P_BLEAF:
 bl = GETBLEAF(rchild, 0);
 nbytes = NBINTERNAL(bl->ksize);
 if (t->bt_pfx && !(bl->flags & P_BIGKEY) &&
 (h->prevpg != P_INVALID || skip > 1)) {
 tbl = GETBLEAF(lchild, NEXTINDEX(lchild) - 1);
 a.size = tbl->ksize;
 a.data = tbl->bytes;
 b.size = bl->ksize;
 b.data = bl->bytes;
 nksize = t->bt_pfx(&a, &b);
 n = NBINTERNAL(nksize);
 if (n < nbytes) {
#ifdef STATISTICS
 bt_pfxsaved += nbytes - n;
#endif
 nbytes = n;
 } else
 nksize = 0;
 } else
 nksize = 0;
 break;
 case P_RINTERNAL:
 case P_RLEAF:
 nbytes = NRINTERNAL;
 break;
 default:
 abort();
 }

 /* Split the parent page if necessary or shift the indices. */
 if ((u_int32_t) (h->upper - h->lower)
 < nbytes + sizeof(indx_t)) {
 sp = h;
 h = h->pgno == P_ROOT ?
 bt_root(t, h, &l, &r, &skip, nbytes) :
 bt_page(t, h, &l, &r, &skip, nbytes);
 if (h == NULL)
 goto err1;
 parentsplit = 1;
 } else {
 if (skip < (nxtindex = NEXTINDEX(h)))
 memmove(h->linp + skip + 1, h->linp + skip,
 (nxtindex - skip) * sizeof(indx_t));
 h->lower += sizeof(indx_t);
 parentsplit = 0;
 }

 /* Insert the key into the parent page. */
 switch (rchild->flags & P_TYPE) {
 case P_BINTERNAL:
 h->linp[skip] = h->upper -= nbytes;
 dest = (char *)h + h->linp[skip];
 memmove(dest, bi, nbytes);
 ((BINTERNAL *)dest)->pgno = rchild->pgno;
 break;
 case P_BLEAF:
 h->linp[skip] = h->upper -= nbytes;
 dest = (char *)h + h->linp[skip];
 WR_BINTERNAL(dest, nksize ? nksize : bl->ksize,
 rchild->pgno, bl->flags & P_BIGKEY);
 memmove(dest, bl->bytes, nksize ? nksize : bl->ksize);
 if (bl->flags & P_BIGKEY &&
 bt_preserve(t, *(pgno_t *)bl->bytes) == RET_ERROR)
 goto err1;
 break;
 case P_RINTERNAL:
 /*
 * Update the left page count. If split
 * added at index 0, fix the correct page.
 */
 if (skip > 0)
 dest = (char *)h + h->linp[skip - 1];
 else
 dest = (char *)l + l->linp[NEXTINDEX(l) - 1];
 ((RINTERNAL *)dest)->nrecs = rec_total(lchild);
 ((RINTERNAL *)dest)->pgno = lchild->pgno;

 /* Update the right page count. */
 h->linp[skip] = h->upper -= nbytes;
 dest = (char *)h + h->linp[skip];
 ((RINTERNAL *)dest)->nrecs = rec_total(rchild);
 ((RINTERNAL *)dest)->pgno = rchild->pgno;
 break;
 case P_RLEAF:
 /*
 * Update the left page count. If split
 * added at index 0, fix the correct page.
 */
 if (skip > 0)
 dest = (char *)h + h->linp[skip - 1];
 else
 dest = (char *)l + l->linp[NEXTINDEX(l) - 1];
 ((RINTERNAL *)dest)->nrecs = NEXTINDEX(lchild);
 ((RINTERNAL *)dest)->pgno = lchild->pgno;

 /* Update the right page count. */
 h->linp[skip] = h->upper -= nbytes;
 dest = (char *)h + h->linp[skip];
 ((RINTERNAL *)dest)->nrecs = NEXTINDEX(rchild);
 ((RINTERNAL *)dest)->pgno = rchild->pgno;
 break;
 default:
 abort();
 }

 /* Unpin the held pages. */
 if (!parentsplit) {
 mpool_put(t->bt_mp, h, MPOOL_DIRTY);
 break;
 }

 /* If the root page was split, make it look right. */
 if (sp->pgno == P_ROOT &&
 (F_ISSET(t, R_RECNO) ?
 bt_rroot(t, sp, l, r) : bt_broot(t, sp, l, r)) == RET_ERROR)
 goto err1;

 mpool_put(t->bt_mp, lchild, MPOOL_DIRTY);
 mpool_put(t->bt_mp, rchild, MPOOL_DIRTY);
 }

 /* Unpin the held pages. */
 mpool_put(t->bt_mp, l, MPOOL_DIRTY);
 mpool_put(t->bt_mp, r, MPOOL_DIRTY);

 /* Clear any pages left on the stack. */
 return (RET_SUCCESS);

 /*
 * If something fails in the above loop we were already walking back
 * up the tree and the tree is now inconsistent. Nothing much we can
 * do about it but release any memory we're holding.
 */
err1: mpool_put(t->bt_mp, lchild, MPOOL_DIRTY);
 mpool_put(t->bt_mp, rchild, MPOOL_DIRTY);

err2: mpool_put(t->bt_mp, l, 0);
 mpool_put(t->bt_mp, r, 0);
 __dbpanic(t->bt_dbp);
 return (RET_ERROR);
}

__P() [1/5]

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

static

__P() [2/5]

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

static

__P() [3/5]

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

static

__P() [4/5]

static PAGE* bt_psplit __P ( (BTREE *, PAGE *, PAGE *, PAGE *, indx_t *, size_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.

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().

{
 BINTERNAL *bi;
 BLEAF *bl;
 u_int32_t nbytes;
 char *dest;

 /*
 * If the root page was a leaf page, change it into an internal page.
 * We copy the key we split on (but not the key's data, in the case of
 * a leaf page) to the new root page.
 *
 * The btree comparison code guarantees that the left-most key on any
 * level of the tree is never used, so it doesn't need to be filled in.
 */
 nbytes = NBINTERNAL(0);
 h->linp[0] = h->upper = t->bt_psize - nbytes;
 dest = (char *)h + h->upper;
 WR_BINTERNAL(dest, 0, l->pgno, 0);

 switch (h->flags & P_TYPE) {
 case P_BLEAF:
 bl = GETBLEAF(r, 0);
 nbytes = NBINTERNAL(bl->ksize);
 h->linp[1] = h->upper -= nbytes;
 dest = (char *)h + h->upper;
 WR_BINTERNAL(dest, bl->ksize, r->pgno, 0);
 memmove(dest, bl->bytes, bl->ksize);

 /*
 * If the key is on an overflow page, mark the overflow chain
 * so it isn't deleted when the leaf copy of the key is deleted.
 */
 if (bl->flags & P_BIGKEY &&
 bt_preserve(t, *(pgno_t *)bl->bytes) == RET_ERROR)
 return (RET_ERROR);
 break;
 case P_BINTERNAL:
 bi = GETBINTERNAL(r, 0);
 nbytes = NBINTERNAL(bi->ksize);
 h->linp[1] = h->upper -= nbytes;
 dest = (char *)h + h->upper;
 memmove(dest, bi, nbytes);
 ((BINTERNAL *)dest)->pgno = r->pgno;
 break;
 default:
 abort();
 }

 /* There are two keys on the page. */
 h->lower = BTDATAOFF + 2 * sizeof(indx_t);

 /* Unpin the root page, set to btree internal page. */
 h->flags &= ~P_TYPE;
 h->flags |= P_BINTERNAL;
 mpool_put(t->bt_mp, h, MPOOL_DIRTY);

 return (RET_SUCCESS);
}

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.

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().

{
 PAGE *l, *r, *tp;
 pgno_t npg;

#ifdef STATISTICS
 ++bt_split;
#endif
 /* Put the new right page for the split into place. */
 if ((r = __bt_new(t, &npg)) == NULL)
 return (NULL);
 r->pgno = npg;
 r->lower = BTDATAOFF;
 r->upper = t->bt_psize;
 r->nextpg = h->nextpg;
 r->prevpg = h->pgno;
 r->flags = h->flags & P_TYPE;

 /*
 * If we're splitting the last page on a level because we're appending
 * a key to it (skip is NEXTINDEX()), it's likely that the data is
 * sorted. Adding an empty page on the side of the level is less work
 * and can push the fill factor much higher than normal. If we're
 * wrong it's no big deal, we'll just do the split the right way next
 * time. It may look like it's equally easy to do a similar hack for
 * reverse sorted data, that is, split the tree left, but it's not.
 * Don't even try.
 */
 if (h->nextpg == P_INVALID && *skip == NEXTINDEX(h)) {
#ifdef STATISTICS
 ++bt_sortsplit;
#endif
 h->nextpg = r->pgno;
 r->lower = BTDATAOFF + sizeof(indx_t);
 *skip = 0;
 *lp = h;
 *rp = r;
 return (r);
 }

 /* Put the new left page for the split into place. */
 if ((l = (PAGE *)malloc(t->bt_psize)) == NULL) {
 mpool_put(t->bt_mp, r, 0);
 return (NULL);
 }
#ifdef PURIFY
 memset(l, 0xff, t->bt_psize);
#endif
 l->pgno = h->pgno;
 l->nextpg = r->pgno;
 l->prevpg = h->prevpg;
 l->lower = BTDATAOFF;
 l->upper = t->bt_psize;
 l->flags = h->flags & P_TYPE;

 /* Fix up the previous pointer of the page after the split page. */
 if (h->nextpg != P_INVALID) {
 if ((tp = mpool_get(t->bt_mp, h->nextpg, 0)) == NULL) {
 free(l);
 /* XXX mpool_free(t->bt_mp, r->pgno); */
 return (NULL);
 }
 tp->prevpg = r->pgno;
 mpool_put(t->bt_mp, tp, MPOOL_DIRTY);
 }

 /*
 * Split right. The key/data pairs aren't sorted in the btree page so
 * it's simpler to copy the data from the split page onto two new pages
 * instead of copying half the data to the right page and compacting
 * the left page in place. Since the left page can't change, we have
 * to swap the original and the allocated left page after the split.
 */
 tp = bt_psplit(t, h, l, r, skip, ilen);

 /* Move the new left page onto the old left page. */
 memmove(h, l, t->bt_psize);
 if (tp == l)
 tp = h;
 free(l);

 *lp = h;
 *rp = r;
 return (tp);
}

bt_preserve()

static int bt_preserve ( BTREE *  t, pgno_t  pg  )

static

Definition at line 792 of file bt_split.c.

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().

{
 PAGE *h;

 if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
 return (RET_ERROR);
 h->flags |= P_PRESERVE;
 mpool_put(t->bt_mp, h, MPOOL_DIRTY);
 return (RET_SUCCESS);
}

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.

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

Referenced by bt_page(), and bt_root().

{
 BINTERNAL *bi;
 BLEAF *bl;
 CURSOR *c;
 RLEAF *rl;
 PAGE *rval;
 void *src = 0;
 indx_t full, half, nxt, off, skip, top, used;
 u_int32_t nbytes;
 int bigkeycnt, isbigkey;

 /*
 * Split the data to the left and right pages. Leave the skip index
 * open. Additionally, make some effort not to split on an overflow
 * key. This makes internal page processing faster and can save
 * space as overflow keys used by internal pages are never deleted.
 */
 bigkeycnt = 0;
 skip = *pskip;
 full = t->bt_psize - BTDATAOFF;
 half = full / 2;
 used = 0;
 for (nxt = off = 0, top = NEXTINDEX(h); nxt < top; ++off) {
 if (skip == off) {
 nbytes = ilen;
 isbigkey = 0; /* XXX: not really known. */
 } else
 switch (h->flags & P_TYPE) {
 case P_BINTERNAL:
 src = bi = GETBINTERNAL(h, nxt);
 nbytes = NBINTERNAL(bi->ksize);
 isbigkey = bi->flags & P_BIGKEY;
 break;
 case P_BLEAF:
 src = bl = GETBLEAF(h, nxt);
 nbytes = NBLEAF(bl);
 isbigkey = bl->flags & P_BIGKEY;
 break;
 case P_RINTERNAL:
 src = GETRINTERNAL(h, nxt);
 nbytes = NRINTERNAL;
 isbigkey = 0;
 break;
 case P_RLEAF:
 src = rl = GETRLEAF(h, nxt);
 nbytes = NRLEAF(rl);
 isbigkey = 0;
 break;
 default:
 abort();
 }

 /*
 * If the key/data pairs are substantial fractions of the max
 * possible size for the page, it's possible to get situations
 * where we decide to try and copy too much onto the left page.
 * Make sure that doesn't happen.
 */
 if ((skip <= off && used + nbytes + sizeof(indx_t) >= full)
 || nxt == top - 1) {
 --off;
 break;
 }

 /* Copy the key/data pair, if not the skipped index. */
 if (skip != off) {
 ++nxt;

 l->linp[off] = l->upper -= nbytes;
 memmove((char *)l + l->upper, src, nbytes);
 }

 used += nbytes + sizeof(indx_t);
 if (used >= half) {
 if (!isbigkey || bigkeycnt == 3)
 break;
 else
 ++bigkeycnt;
 }
 }

 /*
 * Off is the last offset that's valid for the left page.
 * Nxt is the first offset to be placed on the right page.
 */
 l->lower += (off + 1) * sizeof(indx_t);

 /*
 * If splitting the page that the cursor was on, the cursor has to be
 * adjusted to point to the same record as before the split. If the
 * cursor is at or past the skipped slot, the cursor is incremented by
 * one. If the cursor is on the right page, it is decremented by the
 * number of records split to the left page.
 */
 c = &t->bt_cursor;
 if (F_ISSET(c, CURS_INIT) && c->pg.pgno == h->pgno) {
 if (c->pg.index >= skip)
 ++c->pg.index;
 if (c->pg.index < nxt) /* Left page. */
 c->pg.pgno = l->pgno;
 else { /* Right page. */
 c->pg.pgno = r->pgno;
 c->pg.index -= nxt;
 }
 }

 /*
 * If the skipped index was on the left page, just return that page.
 * Otherwise, adjust the skip index to reflect the new position on
 * the right page.
 */
 if (skip <= off) {
 skip = 0;
 rval = l;
 } else {
 rval = r;
 *pskip -= nxt;
 }

 for (off = 0; nxt < top; ++off) {
 if (skip == nxt) {
 ++off;
 skip = 0;
 }
 switch (h->flags & P_TYPE) {
 case P_BINTERNAL:
 src = bi = GETBINTERNAL(h, nxt);
 nbytes = NBINTERNAL(bi->ksize);
 break;
 case P_BLEAF:
 src = bl = GETBLEAF(h, nxt);
 nbytes = NBLEAF(bl);
 break;
 case P_RINTERNAL:
 src = GETRINTERNAL(h, nxt);
 nbytes = NRINTERNAL;
 break;
 case P_RLEAF:
 src = rl = GETRLEAF(h, nxt);
 nbytes = NRLEAF(rl);
 break;
 default:
 abort();
 }
 ++nxt;
 r->linp[off] = r->upper -= nbytes;
 memmove((char *)r + r->upper, src, nbytes);
 }
 r->lower += off * sizeof(indx_t);

 /* If the key is being appended to the page, adjust the index. */
 if (skip == top)
 r->lower += sizeof(indx_t);

 return (rval);
}

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.

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().

{
 PAGE *l, *r, *tp;
 pgno_t lnpg, rnpg;

#ifdef STATISTICS
 ++bt_split;
 ++bt_rootsplit;
#endif
 /* Put the new left and right pages for the split into place. */
 if ((l = __bt_new(t, &lnpg)) == NULL ||
 (r = __bt_new(t, &rnpg)) == NULL)
 return (NULL);
 l->pgno = lnpg;
 r->pgno = rnpg;
 l->nextpg = r->pgno;
 r->prevpg = l->pgno;
 l->prevpg = r->nextpg = P_INVALID;
 l->lower = r->lower = BTDATAOFF;
 l->upper = r->upper = t->bt_psize;
 l->flags = r->flags = h->flags & P_TYPE;

 /* Split the root page. */
 tp = bt_psplit(t, h, l, r, skip, ilen);

 *lp = l;
 *rp = r;
 return (tp);
}

bt_rroot()

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

static

Definition at line 497 of file bt_split.c.

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

Referenced by __bt_split().

{
 char *dest;

 /* Insert the left and right keys, set the header information. */
 h->linp[0] = h->upper = t->bt_psize - NRINTERNAL;
 dest = (char *)h + h->upper;
 WR_RINTERNAL(dest,
 l->flags & P_RLEAF ? NEXTINDEX(l) : rec_total(l), l->pgno);

 h->linp[1] = h->upper -= NRINTERNAL;
 dest = (char *)h + h->upper;
 WR_RINTERNAL(dest,
 r->flags & P_RLEAF ? NEXTINDEX(r) : rec_total(r), r->pgno);

 h->lower = BTDATAOFF + 2 * sizeof(indx_t);

 /* Unpin the root page, set to recno internal page. */
 h->flags &= ~P_TYPE;
 h->flags |= P_RINTERNAL;
 mpool_put(t->bt_mp, h, MPOOL_DIRTY);

 return (RET_SUCCESS);
}

rec_total()

static recno_t rec_total ( PAGE *  h )

static

Definition at line 820 of file bt_split.c.

References GETRINTERNAL, and NEXTINDEX.

Referenced by __bt_split(), and bt_rroot().

{
 recno_t recs;
 indx_t nxt, top;

 for (recs = 0, nxt = 0, top = NEXTINDEX(h); nxt < top; ++nxt)
 recs += GETRINTERNAL(h, nxt)->nrecs;
 return (recs);
}