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412 lines
11 KiB
412 lines
11 KiB
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1996, 1997, 1998, 1999
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* Sleepycat Software. All rights reserved.
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*/
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/*
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* Copyright (c) 1990, 1993, 1994, 1995, 1996
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* Keith Bostic. All rights reserved.
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*/
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/*
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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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. 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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#include "db_config.h"
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#ifndef lint
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static const char sccsid[] = "@(#)bt_rsearch.c 11.8 (Sleepycat) 10/21/99";
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#endif /* not lint */
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#ifndef NO_SYSTEM_INCLUDES
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#include <sys/types.h>
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#endif
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#include "db_int.h"
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#include "db_page.h"
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#include "btree.h"
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/*
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* CDB___bam_rsearch --
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* Search a btree for a record number.
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*
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* PUBLIC: int CDB___bam_rsearch __P((DBC *, db_recno_t *, u_int32_t, int, int *));
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*/
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int
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CDB___bam_rsearch(dbc, recnop, flags, stop, exactp)
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DBC *dbc;
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db_recno_t *recnop;
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u_int32_t flags;
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int stop, *exactp;
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{
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BINTERNAL *bi;
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BTREE_CURSOR *cp;
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DB *dbp;
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DB_LOCK lock;
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PAGE *h;
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RINTERNAL *ri;
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db_indx_t indx, top;
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db_lockmode_t lock_mode;
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db_pgno_t pg;
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db_recno_t i, recno, total;
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int ret, stack;
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dbp = dbc->dbp;
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cp = dbc->internal;
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BT_STK_CLR(cp);
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/*
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* There are several ways we search a btree tree. The flags argument
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* specifies if we're acquiring read or write locks and if we are
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* locking pairs of pages. In addition, if we're adding or deleting
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* an item, we have to lock the entire tree, regardless. See btree.h
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* for more details.
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*
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* If write-locking pages, we need to know whether or not to acquire a
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* write lock on a page before getting it. This depends on how deep it
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* is in tree, which we don't know until we acquire the root page. So,
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* if we need to lock the root page we may have to upgrade it later,
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* because we won't get the correct lock initially.
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*
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* Retrieve the root page.
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*/
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pg = ((BTREE *)dbp->bt_internal)->bt_root;
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stack = LF_ISSET(S_STACK);
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lock_mode = stack ? DB_LOCK_WRITE : DB_LOCK_READ;
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if ((ret = CDB___db_lget(dbc, 0, pg, lock_mode, 0, &lock)) != 0)
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return (ret);
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if ((ret = CDB_memp_fget(dbp->mpf, &pg, 0, &h)) != 0) {
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/* Did not read it, so we can release the lock */
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(void)__LPUT(dbc, lock);
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return (ret);
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}
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/*
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* Decide if we need to save this page; if we do, write lock it.
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* We deliberately don't lock-couple on this call. If the tree
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* is tiny, i.e., one page, and two threads are busily updating
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* the root page, we're almost guaranteed deadlocks galore, as
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* each one gets a read lock and then blocks the other's attempt
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* for a write lock.
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*/
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if (!stack &&
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((LF_ISSET(S_PARENT) && (u_int8_t)(stop + 1) >= h->level) ||
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(LF_ISSET(S_WRITE) && h->level == LEAFLEVEL))) {
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(void)CDB_memp_fput(dbp->mpf, h, 0);
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(void)__LPUT(dbc, lock);
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lock_mode = DB_LOCK_WRITE;
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if ((ret = CDB___db_lget(dbc, 0, pg, lock_mode, 0, &lock)) != 0)
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return (ret);
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if ((ret = CDB_memp_fget(dbp->mpf, &pg, 0, &h)) != 0) {
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/* Did not read it, so we can release the lock */
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(void)__LPUT(dbc, lock);
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return (ret);
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}
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stack = 1;
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}
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/*
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* If appending to the tree, set the record number now -- we have the
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* root page locked.
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*
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* Delete only deletes exact matches, read only returns exact matches.
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* Note, this is different from CDB___bam_search(), which returns non-exact
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* matches for read.
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*
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* The record may not exist. We can only return the correct location
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* for the record immediately after the last record in the tree, so do
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* a fast check now.
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*/
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total = RE_NREC(h);
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if (LF_ISSET(S_APPEND)) {
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*exactp = 0;
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*recnop = recno = total + 1;
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} else {
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recno = *recnop;
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if (recno <= total)
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*exactp = 1;
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else {
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*exactp = 0;
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if (!LF_ISSET(S_PAST_EOF) || recno > total + 1) {
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/*
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* Keep the page locked for serializability.
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*
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* XXX
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* This leaves the root page locked, which will
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* eliminate any concurrency. A possible fix
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* would be to lock the last leaf page instead.
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*/
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(void)CDB_memp_fput(dbp->mpf, h, 0);
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(void)__TLPUT(dbc, lock);
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return (DB_NOTFOUND);
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}
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}
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}
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/*
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* !!!
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* Record numbers in the tree are 0-based, but the recno is
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* 1-based. All of the calculations below have to take this
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* into account.
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*/
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for (total = 0;;) {
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switch (TYPE(h)) {
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case P_LBTREE:
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recno -= total;
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/*
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* There may be logically deleted records on the page,
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* walk the page correcting for them. The record may
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* not exist if there are enough deleted records in the
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* page.
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*/
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if (recno <= (db_recno_t)NUM_ENT(h) / P_INDX)
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for (i = recno - 1;; --i) {
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if (B_DISSET(GET_BKEYDATA(h,
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i * P_INDX + O_INDX)->type))
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++recno;
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if (i == 0)
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break;
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}
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if (recno > (db_recno_t)NUM_ENT(h) / P_INDX) {
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*exactp = 0;
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if (!LF_ISSET(S_PAST_EOF) || recno >
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(db_recno_t)(NUM_ENT(h) / P_INDX + 1)) {
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ret = DB_NOTFOUND;
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goto err;
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}
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}
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/* Correct from 1-based to 0-based for a page offset. */
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--recno;
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BT_STK_ENTER(cp,
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h, recno * P_INDX, lock, lock_mode, ret);
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return (ret);
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case P_IBTREE:
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for (indx = 0, top = NUM_ENT(h);;) {
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bi = GET_BINTERNAL(h, indx);
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if (++indx == top || total + bi->nrecs >= recno)
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break;
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total += bi->nrecs;
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}
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pg = bi->pgno;
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break;
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case P_LRECNO:
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recno -= total;
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/* Correct from 1-based to 0-based for a page offset. */
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--recno;
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BT_STK_ENTER(cp, h, recno, lock, lock_mode, ret);
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return (ret);
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case P_IRECNO:
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for (indx = 0, top = NUM_ENT(h);;) {
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ri = GET_RINTERNAL(h, indx);
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if (++indx == top || total + ri->nrecs >= recno)
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break;
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total += ri->nrecs;
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}
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pg = ri->pgno;
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break;
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default:
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return (CDB___db_pgfmt(dbp, h->pgno));
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}
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--indx;
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if (stack) {
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/* Return if this is the lowest page wanted. */
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if (LF_ISSET(S_PARENT) && stop == h->level) {
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BT_STK_ENTER(cp, h, indx, lock, lock_mode, ret);
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return (ret);
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}
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BT_STK_PUSH(cp, h, indx, lock, lock_mode, ret);
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if (ret != 0)
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goto err;
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lock_mode = DB_LOCK_WRITE;
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if ((ret =
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CDB___db_lget(dbc, 0, pg, lock_mode, 0, &lock)) != 0)
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goto err;
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} else {
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/*
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* Decide if we want to return a pointer to the next
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* page in the stack. If we do, write lock it and
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* never unlock it.
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*/
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if ((LF_ISSET(S_PARENT) &&
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(u_int8_t)(stop + 1) >= (u_int8_t)(h->level - 1)) ||
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(h->level - 1) == LEAFLEVEL)
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stack = 1;
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(void)CDB_memp_fput(dbp->mpf, h, 0);
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lock_mode = stack &&
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LF_ISSET(S_WRITE) ? DB_LOCK_WRITE : DB_LOCK_READ;
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if ((ret =
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CDB___db_lget(dbc, 1, pg, lock_mode, 0, &lock)) != 0) {
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/*
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* If we fail, discard the lock we held. This
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* is OK because this only happens when we are
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* descending the tree holding read-locks.
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*/
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__LPUT(dbc, lock);
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goto err;
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}
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}
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if ((ret = CDB_memp_fget(dbp->mpf, &pg, 0, &h)) != 0)
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goto err;
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}
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/* NOTREACHED */
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err: BT_STK_POP(cp);
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CDB___bam_stkrel(dbc, 0);
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return (ret);
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}
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/*
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* CDB___bam_adjust --
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* Adjust the tree after adding or deleting a record.
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*
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* PUBLIC: int CDB___bam_adjust __P((DBC *, int32_t));
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*/
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int
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CDB___bam_adjust(dbc, adjust)
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DBC *dbc;
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int32_t adjust;
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{
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BTREE_CURSOR *cp;
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DB *dbp;
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EPG *epg;
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PAGE *h;
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db_pgno_t root_pgno;
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int ret;
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dbp = dbc->dbp;
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cp = dbc->internal;
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root_pgno = ((BTREE *)dbp->bt_internal)->bt_root;
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/* Update the record counts for the tree. */
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for (epg = cp->sp; epg <= cp->csp; ++epg) {
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h = epg->page;
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if (TYPE(h) == P_IBTREE || TYPE(h) == P_IRECNO) {
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if (DB_LOGGING(dbc) &&
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(ret = CDB___bam_cadjust_log(dbp->dbenv,
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dbc->txn, &LSN(h), 0, dbp->log_fileid,
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PGNO(h), &LSN(h), (u_int32_t)epg->indx,
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adjust, 1)) != 0)
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return (ret);
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if (TYPE(h) == P_IBTREE)
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GET_BINTERNAL(h, epg->indx)->nrecs += adjust;
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else
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GET_RINTERNAL(h, epg->indx)->nrecs += adjust;
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if (PGNO(h) == root_pgno)
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RE_NREC_ADJ(h, adjust);
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if ((ret = CDB_memp_fset(dbp->mpf, h, DB_MPOOL_DIRTY)) != 0)
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return (ret);
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}
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}
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return (0);
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}
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/*
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* CDB___bam_nrecs --
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* Return the number of records in the tree.
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*
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* PUBLIC: int CDB___bam_nrecs __P((DBC *, db_recno_t *));
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*/
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int
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CDB___bam_nrecs(dbc, rep)
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DBC *dbc;
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db_recno_t *rep;
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{
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DB *dbp;
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DB_LOCK lock;
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PAGE *h;
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db_pgno_t pgno;
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int ret;
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dbp = dbc->dbp;
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pgno = ((BTREE *)dbp->bt_internal)->bt_root;
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if ((ret = CDB___db_lget(dbc, 0, pgno, DB_LOCK_READ, 0, &lock)) != 0)
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return (ret);
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if ((ret = CDB_memp_fget(dbp->mpf, &pgno, 0, &h)) != 0)
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return (ret);
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*rep = RE_NREC(h);
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(void)CDB_memp_fput(dbp->mpf, h, 0);
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(void)__TLPUT(dbc, lock);
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return (0);
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}
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/*
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* CDB___bam_total --
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* Return the number of records below a page.
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*
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* PUBLIC: db_recno_t CDB___bam_total __P((PAGE *));
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*/
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db_recno_t
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CDB___bam_total(h)
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PAGE *h;
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{
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db_recno_t nrecs;
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db_indx_t indx, top;
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nrecs = 0;
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top = NUM_ENT(h);
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switch (TYPE(h)) {
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case P_LBTREE:
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/* Check for logically deleted records. */
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for (indx = 0; indx < top; indx += P_INDX)
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if (!B_DISSET(GET_BKEYDATA(h, indx + O_INDX)->type))
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++nrecs;
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break;
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case P_IBTREE:
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for (indx = 0; indx < top; indx += O_INDX)
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nrecs += GET_BINTERNAL(h, indx)->nrecs;
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break;
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case P_LRECNO:
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nrecs = NUM_ENT(h);
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break;
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case P_IRECNO:
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for (indx = 0; indx < top; indx += O_INDX)
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nrecs += GET_RINTERNAL(h, indx)->nrecs;
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break;
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}
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return (nrecs);
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}
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