git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@578 65c4cc65-6c06-0410-ace0-fbb531ad65f3
830 lines
22 KiB
C
Executable file
830 lines
22 KiB
C
Executable file
/*-
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* Copyright (c) 1990, 1993, 1994
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Mike Olson.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)bt_split.c 8.9 (Berkeley) 7/26/94";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/types.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <db.h>
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#include "btree.h"
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static int bt_broot __P((BTREE *, PAGE *, PAGE *, PAGE *));
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static PAGE *bt_page
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__P((BTREE *, PAGE *, PAGE **, PAGE **, indx_t *, size_t));
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static int bt_preserve __P((BTREE *, pgno_t));
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static PAGE *bt_psplit
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__P((BTREE *, PAGE *, PAGE *, PAGE *, indx_t *, size_t));
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static PAGE *bt_root
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__P((BTREE *, PAGE *, PAGE **, PAGE **, indx_t *, size_t));
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static int bt_rroot __P((BTREE *, PAGE *, PAGE *, PAGE *));
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static recno_t rec_total __P((PAGE *));
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#ifdef STATISTICS
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u_long bt_rootsplit, bt_split, bt_sortsplit, bt_pfxsaved;
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#endif
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/*
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* __BT_SPLIT -- Split the tree.
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*
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* Parameters:
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* t: tree
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* sp: page to split
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* key: key to insert
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* data: data to insert
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* flags: BIGKEY/BIGDATA flags
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* ilen: insert length
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* skip: index to leave open
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*
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* Returns:
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* RET_ERROR, RET_SUCCESS
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*/
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int
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__bt_split(t, sp, key, data, flags, ilen, argskip)
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BTREE *t;
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PAGE *sp;
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const DBT *key, *data;
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int flags;
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size_t ilen;
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u_int32_t argskip;
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{
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BINTERNAL *bi;
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BLEAF *bl, *tbl;
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DBT a, b;
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EPGNO *parent;
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PAGE *h, *l, *r, *lchild, *rchild;
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indx_t nxtindex;
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u_int16_t skip;
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u_int32_t n, nbytes, nksize;
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int parentsplit;
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char *dest;
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/*
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* Split the page into two pages, l and r. The split routines return
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* a pointer to the page into which the key should be inserted and with
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* skip set to the offset which should be used. Additionally, l and r
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* are pinned.
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*/
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skip = argskip;
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h = sp->pgno == P_ROOT ?
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bt_root(t, sp, &l, &r, &skip, ilen) :
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bt_page(t, sp, &l, &r, &skip, ilen);
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if (h == NULL)
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return (RET_ERROR);
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/*
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* Insert the new key/data pair into the leaf page. (Key inserts
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* always cause a leaf page to split first.)
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*/
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h->linp[skip] = h->upper -= ilen;
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dest = (char *)h + h->upper;
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if (F_ISSET(t, R_RECNO))
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WR_RLEAF(dest, data, flags)
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else
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WR_BLEAF(dest, key, data, flags)
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/* If the root page was split, make it look right. */
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if (sp->pgno == P_ROOT &&
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(F_ISSET(t, R_RECNO) ?
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bt_rroot(t, sp, l, r) : bt_broot(t, sp, l, r)) == RET_ERROR)
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goto err2;
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/*
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* Now we walk the parent page stack -- a LIFO stack of the pages that
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* were traversed when we searched for the page that split. Each stack
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* entry is a page number and a page index offset. The offset is for
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* the page traversed on the search. We've just split a page, so we
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* have to insert a new key into the parent page.
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*
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* If the insert into the parent page causes it to split, may have to
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* continue splitting all the way up the tree. We stop if the root
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* splits or the page inserted into didn't have to split to hold the
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* new key. Some algorithms replace the key for the old page as well
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* as the new page. We don't, as there's no reason to believe that the
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* first key on the old page is any better than the key we have, and,
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* in the case of a key being placed at index 0 causing the split, the
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* key is unavailable.
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*
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* There are a maximum of 5 pages pinned at any time. We keep the left
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* and right pages pinned while working on the parent. The 5 are the
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* two children, left parent and right parent (when the parent splits)
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* and the root page or the overflow key page when calling bt_preserve.
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* This code must make sure that all pins are released other than the
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* root page or overflow page which is unlocked elsewhere.
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*/
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while ((parent = BT_POP(t)) != NULL) {
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lchild = l;
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rchild = r;
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/* Get the parent page. */
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if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
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goto err2;
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/*
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* The new key goes ONE AFTER the index, because the split
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* was to the right.
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*/
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skip = parent->index + 1;
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/*
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* Calculate the space needed on the parent page.
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*
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* Prefix trees: space hack when inserting into BINTERNAL
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* pages. Retain only what's needed to distinguish between
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* the new entry and the LAST entry on the page to its left.
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* If the keys compare equal, retain the entire key. Note,
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* we don't touch overflow keys, and the entire key must be
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* retained for the next-to-left most key on the leftmost
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* page of each level, or the search will fail. Applicable
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* ONLY to internal pages that have leaf pages as children.
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* Further reduction of the key between pairs of internal
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* pages loses too much information.
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*/
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switch (rchild->flags & P_TYPE) {
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case P_BINTERNAL:
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bi = GETBINTERNAL(rchild, 0);
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nbytes = NBINTERNAL(bi->ksize);
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break;
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case P_BLEAF:
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bl = GETBLEAF(rchild, 0);
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nbytes = NBINTERNAL(bl->ksize);
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if (t->bt_pfx && !(bl->flags & P_BIGKEY) &&
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(h->prevpg != P_INVALID || skip > 1)) {
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tbl = GETBLEAF(lchild, NEXTINDEX(lchild) - 1);
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a.size = tbl->ksize;
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a.data = tbl->bytes;
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b.size = bl->ksize;
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b.data = bl->bytes;
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nksize = t->bt_pfx(&a, &b);
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n = NBINTERNAL(nksize);
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if (n < nbytes) {
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#ifdef STATISTICS
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bt_pfxsaved += nbytes - n;
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#endif
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nbytes = n;
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} else
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nksize = 0;
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} else
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nksize = 0;
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break;
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case P_RINTERNAL:
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case P_RLEAF:
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nbytes = NRINTERNAL;
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break;
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default:
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abort();
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}
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/* Split the parent page if necessary or shift the indices. */
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if ((u_int32_t) (h->upper - h->lower)
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< nbytes + sizeof(indx_t)) {
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sp = h;
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h = h->pgno == P_ROOT ?
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bt_root(t, h, &l, &r, &skip, nbytes) :
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bt_page(t, h, &l, &r, &skip, nbytes);
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if (h == NULL)
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goto err1;
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parentsplit = 1;
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} else {
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if (skip < (nxtindex = NEXTINDEX(h)))
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memmove(h->linp + skip + 1, h->linp + skip,
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(nxtindex - skip) * sizeof(indx_t));
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h->lower += sizeof(indx_t);
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parentsplit = 0;
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}
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/* Insert the key into the parent page. */
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switch (rchild->flags & P_TYPE) {
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case P_BINTERNAL:
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h->linp[skip] = h->upper -= nbytes;
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dest = (char *)h + h->linp[skip];
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memmove(dest, bi, nbytes);
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((BINTERNAL *)dest)->pgno = rchild->pgno;
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break;
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case P_BLEAF:
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h->linp[skip] = h->upper -= nbytes;
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dest = (char *)h + h->linp[skip];
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WR_BINTERNAL(dest, nksize ? nksize : bl->ksize,
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rchild->pgno, bl->flags & P_BIGKEY);
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memmove(dest, bl->bytes, nksize ? nksize : bl->ksize);
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if (bl->flags & P_BIGKEY &&
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bt_preserve(t, *(pgno_t *)bl->bytes) == RET_ERROR)
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goto err1;
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break;
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case P_RINTERNAL:
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/*
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* Update the left page count. If split
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* added at index 0, fix the correct page.
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*/
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if (skip > 0)
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dest = (char *)h + h->linp[skip - 1];
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else
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dest = (char *)l + l->linp[NEXTINDEX(l) - 1];
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((RINTERNAL *)dest)->nrecs = rec_total(lchild);
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((RINTERNAL *)dest)->pgno = lchild->pgno;
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/* Update the right page count. */
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h->linp[skip] = h->upper -= nbytes;
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dest = (char *)h + h->linp[skip];
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((RINTERNAL *)dest)->nrecs = rec_total(rchild);
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((RINTERNAL *)dest)->pgno = rchild->pgno;
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break;
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case P_RLEAF:
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/*
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* Update the left page count. If split
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* added at index 0, fix the correct page.
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*/
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if (skip > 0)
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dest = (char *)h + h->linp[skip - 1];
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else
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dest = (char *)l + l->linp[NEXTINDEX(l) - 1];
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((RINTERNAL *)dest)->nrecs = NEXTINDEX(lchild);
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((RINTERNAL *)dest)->pgno = lchild->pgno;
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/* Update the right page count. */
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h->linp[skip] = h->upper -= nbytes;
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dest = (char *)h + h->linp[skip];
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((RINTERNAL *)dest)->nrecs = NEXTINDEX(rchild);
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((RINTERNAL *)dest)->pgno = rchild->pgno;
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break;
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default:
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abort();
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}
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/* Unpin the held pages. */
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if (!parentsplit) {
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mpool_put(t->bt_mp, h, MPOOL_DIRTY);
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break;
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}
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/* If the root page was split, make it look right. */
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if (sp->pgno == P_ROOT &&
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(F_ISSET(t, R_RECNO) ?
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bt_rroot(t, sp, l, r) : bt_broot(t, sp, l, r)) == RET_ERROR)
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goto err1;
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mpool_put(t->bt_mp, lchild, MPOOL_DIRTY);
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mpool_put(t->bt_mp, rchild, MPOOL_DIRTY);
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}
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/* Unpin the held pages. */
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mpool_put(t->bt_mp, l, MPOOL_DIRTY);
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mpool_put(t->bt_mp, r, MPOOL_DIRTY);
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/* Clear any pages left on the stack. */
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return (RET_SUCCESS);
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/*
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* If something fails in the above loop we were already walking back
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* up the tree and the tree is now inconsistent. Nothing much we can
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* do about it but release any memory we're holding.
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*/
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err1: mpool_put(t->bt_mp, lchild, MPOOL_DIRTY);
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mpool_put(t->bt_mp, rchild, MPOOL_DIRTY);
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err2: mpool_put(t->bt_mp, l, 0);
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mpool_put(t->bt_mp, r, 0);
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__dbpanic(t->bt_dbp);
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return (RET_ERROR);
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}
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/*
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* BT_PAGE -- Split a non-root page of a btree.
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*
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* Parameters:
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* t: tree
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* h: root page
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* lp: pointer to left page pointer
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* rp: pointer to right page pointer
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* skip: pointer to index to leave open
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* ilen: insert length
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*
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* Returns:
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* Pointer to page in which to insert or NULL on error.
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*/
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static PAGE *
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bt_page(t, h, lp, rp, skip, ilen)
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BTREE *t;
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PAGE *h, **lp, **rp;
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indx_t *skip;
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size_t ilen;
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{
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PAGE *l, *r, *tp;
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pgno_t npg;
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#ifdef STATISTICS
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++bt_split;
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#endif
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/* Put the new right page for the split into place. */
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if ((r = __bt_new(t, &npg)) == NULL)
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return (NULL);
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r->pgno = npg;
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r->lower = BTDATAOFF;
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r->upper = t->bt_psize;
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r->nextpg = h->nextpg;
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r->prevpg = h->pgno;
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r->flags = h->flags & P_TYPE;
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/*
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* If we're splitting the last page on a level because we're appending
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* a key to it (skip is NEXTINDEX()), it's likely that the data is
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* sorted. Adding an empty page on the side of the level is less work
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* and can push the fill factor much higher than normal. If we're
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* wrong it's no big deal, we'll just do the split the right way next
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* time. It may look like it's equally easy to do a similar hack for
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* reverse sorted data, that is, split the tree left, but it's not.
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* Don't even try.
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*/
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if (h->nextpg == P_INVALID && *skip == NEXTINDEX(h)) {
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#ifdef STATISTICS
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++bt_sortsplit;
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#endif
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h->nextpg = r->pgno;
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r->lower = BTDATAOFF + sizeof(indx_t);
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*skip = 0;
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*lp = h;
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*rp = r;
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return (r);
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}
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/* Put the new left page for the split into place. */
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if ((l = (PAGE *)malloc(t->bt_psize)) == NULL) {
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mpool_put(t->bt_mp, r, 0);
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return (NULL);
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}
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#ifdef PURIFY
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memset(l, 0xff, t->bt_psize);
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#endif
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l->pgno = h->pgno;
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l->nextpg = r->pgno;
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l->prevpg = h->prevpg;
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l->lower = BTDATAOFF;
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l->upper = t->bt_psize;
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l->flags = h->flags & P_TYPE;
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/* Fix up the previous pointer of the page after the split page. */
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if (h->nextpg != P_INVALID) {
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if ((tp = mpool_get(t->bt_mp, h->nextpg, 0)) == NULL) {
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free(l);
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/* XXX mpool_free(t->bt_mp, r->pgno); */
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return (NULL);
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}
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tp->prevpg = r->pgno;
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mpool_put(t->bt_mp, tp, MPOOL_DIRTY);
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}
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/*
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* Split right. The key/data pairs aren't sorted in the btree page so
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* it's simpler to copy the data from the split page onto two new pages
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* instead of copying half the data to the right page and compacting
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* the left page in place. Since the left page can't change, we have
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* to swap the original and the allocated left page after the split.
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*/
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tp = bt_psplit(t, h, l, r, skip, ilen);
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/* Move the new left page onto the old left page. */
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memmove(h, l, t->bt_psize);
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if (tp == l)
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tp = h;
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free(l);
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*lp = h;
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*rp = r;
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return (tp);
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}
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/*
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* BT_ROOT -- Split the root page of a btree.
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*
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* Parameters:
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* t: tree
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* h: root page
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* lp: pointer to left page pointer
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* rp: pointer to right page pointer
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* skip: pointer to index to leave open
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* ilen: insert length
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*
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* Returns:
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* Pointer to page in which to insert or NULL on error.
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*/
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static PAGE *
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bt_root(t, h, lp, rp, skip, ilen)
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BTREE *t;
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PAGE *h, **lp, **rp;
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indx_t *skip;
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size_t ilen;
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{
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PAGE *l, *r, *tp;
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pgno_t lnpg, rnpg;
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#ifdef STATISTICS
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++bt_split;
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++bt_rootsplit;
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#endif
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/* Put the new left and right pages for the split into place. */
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if ((l = __bt_new(t, &lnpg)) == NULL ||
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(r = __bt_new(t, &rnpg)) == NULL)
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return (NULL);
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l->pgno = lnpg;
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r->pgno = rnpg;
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l->nextpg = r->pgno;
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r->prevpg = l->pgno;
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l->prevpg = r->nextpg = P_INVALID;
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l->lower = r->lower = BTDATAOFF;
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l->upper = r->upper = t->bt_psize;
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l->flags = r->flags = h->flags & P_TYPE;
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/* Split the root page. */
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tp = bt_psplit(t, h, l, r, skip, ilen);
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*lp = l;
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*rp = r;
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return (tp);
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}
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|
|
/*
|
|
* BT_RROOT -- Fix up the recno root page after it has been split.
|
|
*
|
|
* Parameters:
|
|
* t: tree
|
|
* h: root page
|
|
* l: left page
|
|
* r: right page
|
|
*
|
|
* Returns:
|
|
* RET_ERROR, RET_SUCCESS
|
|
*/
|
|
static int
|
|
bt_rroot(t, h, l, r)
|
|
BTREE *t;
|
|
PAGE *h, *l, *r;
|
|
{
|
|
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);
|
|
}
|
|
|
|
/*
|
|
* BT_BROOT -- Fix up the btree root page after it has been split.
|
|
*
|
|
* Parameters:
|
|
* t: tree
|
|
* h: root page
|
|
* l: left page
|
|
* r: right page
|
|
*
|
|
* Returns:
|
|
* RET_ERROR, RET_SUCCESS
|
|
*/
|
|
static int
|
|
bt_broot(t, h, l, r)
|
|
BTREE *t;
|
|
PAGE *h, *l, *r;
|
|
{
|
|
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_PSPLIT -- Do the real work of splitting the page.
|
|
*
|
|
* Parameters:
|
|
* t: tree
|
|
* h: page to be split
|
|
* l: page to put lower half of data
|
|
* r: page to put upper half of data
|
|
* pskip: pointer to index to leave open
|
|
* ilen: insert length
|
|
*
|
|
* Returns:
|
|
* Pointer to page in which to insert.
|
|
*/
|
|
static PAGE *
|
|
bt_psplit(t, h, l, r, pskip, ilen)
|
|
BTREE *t;
|
|
PAGE *h, *l, *r;
|
|
indx_t *pskip;
|
|
size_t ilen;
|
|
{
|
|
BINTERNAL *bi;
|
|
BLEAF *bl;
|
|
CURSOR *c;
|
|
RLEAF *rl;
|
|
PAGE *rval;
|
|
void *src;
|
|
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_PRESERVE -- Mark a chain of pages as used by an internal node.
|
|
*
|
|
* Chains of indirect blocks pointed to by leaf nodes get reclaimed when the
|
|
* record that references them gets deleted. Chains pointed to by internal
|
|
* pages never get deleted. This routine marks a chain as pointed to by an
|
|
* internal page.
|
|
*
|
|
* Parameters:
|
|
* t: tree
|
|
* pg: page number of first page in the chain.
|
|
*
|
|
* Returns:
|
|
* RET_SUCCESS, RET_ERROR.
|
|
*/
|
|
static int
|
|
bt_preserve(t, pg)
|
|
BTREE *t;
|
|
pgno_t pg;
|
|
{
|
|
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);
|
|
}
|
|
|
|
/*
|
|
* REC_TOTAL -- Return the number of recno entries below a page.
|
|
*
|
|
* Parameters:
|
|
* h: page
|
|
*
|
|
* Returns:
|
|
* The number of recno entries below a page.
|
|
*
|
|
* XXX
|
|
* These values could be set by the bt_psplit routine. The problem is that the
|
|
* entry has to be popped off of the stack etc. or the values have to be passed
|
|
* all the way back to bt_split/bt_rroot and it's not very clean.
|
|
*/
|
|
static recno_t
|
|
rec_total(h)
|
|
PAGE *h;
|
|
{
|
|
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);
|
|
}
|