Import BSDDB 4.7.25 (as of svn r89086)
This commit is contained in:
Zachary Ware
340
dbinc/btree.h
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340
dbinc/btree.h
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/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1996,2008 Oracle. 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, 1994, 1995
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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. 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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* $Id: btree.h 63573 2008-05-23 21:43:21Z trent.nelson $
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*/
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#ifndef _DB_BTREE_H_
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#define _DB_BTREE_H_
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#if defined(__cplusplus)
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extern "C" {
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#endif
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/* Forward structure declarations. */
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struct __btree; typedef struct __btree BTREE;
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struct __cursor; typedef struct __cursor BTREE_CURSOR;
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struct __epg; typedef struct __epg EPG;
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#define DEFMINKEYPAGE (2)
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/*
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* A recno order of 0 indicates that we don't have an order, not that we've
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* an order less than 1.
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*/
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#define INVALID_ORDER 0
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#define ISINTERNAL(p) (TYPE(p) == P_IBTREE || TYPE(p) == P_IRECNO)
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#define ISLEAF(p) (TYPE(p) == P_LBTREE || \
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TYPE(p) == P_LRECNO || TYPE(p) == P_LDUP)
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/* Flags for __bam_cadjust_log(). */
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#define CAD_UPDATEROOT 0x01 /* Root page count was updated. */
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/* Flags for __bam_split_log(). */
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#define SPL_NRECS 0x01 /* Split tree has record count. */
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/* Flags for __bam_iitem(). */
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#define BI_DELETED 0x01 /* Key/data pair only placeholder. */
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/* Flags for __bam_stkrel(). */
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#define STK_CLRDBC 0x01 /* Clear dbc->page reference. */
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#define STK_NOLOCK 0x02 /* Don't retain locks. */
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#define STK_PGONLY 0x04
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/* Flags for __ram_ca(). These get logged, so make the values explicit. */
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typedef enum {
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CA_DELETE = 0, /* Delete the current record. */
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CA_IAFTER = 1, /* Insert before the current record. */
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CA_IBEFORE = 2, /* Insert after the current record. */
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CA_ICURRENT = 3 /* Overwrite the current record. */
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} ca_recno_arg;
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/*
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* Flags for __bam_search() and __bam_rsearch().
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*
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* Note, internal page searches must find the largest record less than key in
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* the tree so that descents work. Leaf page searches must find the smallest
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* record greater than key so that the returned index is the record's correct
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* position for insertion.
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*
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* The flags parameter to the search routines describes three aspects of the
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* search: the type of locking required (including if we're locking a pair of
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* pages), the item to return in the presence of duplicates and whether or not
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* to return deleted entries. To simplify both the mnemonic representation
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* and the code that checks for various cases, we construct a set of bitmasks.
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*/
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#define SR_READ 0x00001 /* Read locks. */
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#define SR_WRITE 0x00002 /* Write locks. */
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#define SR_APPEND 0x00040 /* Append to the tree. */
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#define SR_DELNO 0x00080 /* Don't return deleted items. */
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#define SR_DUPFIRST 0x00100 /* Return first duplicate. */
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#define SR_DUPLAST 0x00200 /* Return last duplicate. */
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#define SR_EXACT 0x00400 /* Exact items only. */
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#define SR_PARENT 0x00800 /* Lock page pair. */
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#define SR_STACK 0x01000 /* Need a complete stack. */
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#define SR_PAST_EOF 0x02000 /* If doing insert search (or keyfirst
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* or keylast operations), or a split
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* on behalf of an insert, it's okay to
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* return an entry one past end-of-page.
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*/
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#define SR_STK_ONLY 0x04000 /* Just return info in the stack */
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#define SR_MAX 0x08000 /* Get the right most key */
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#define SR_MIN 0x10000 /* Get the left most key */
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#define SR_NEXT 0x20000 /* Get the page after this key */
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#define SR_DEL 0x40000 /* Get the tree to delete this key. */
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#define SR_START 0x80000 /* Level to start stack. */
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#define SR_DELETE \
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(SR_WRITE | SR_DUPFIRST | SR_DELNO | SR_EXACT | SR_STACK)
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#define SR_FIND (SR_READ | SR_DUPFIRST | SR_DELNO)
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#define SR_FIND_WR (SR_WRITE | SR_DUPFIRST | SR_DELNO)
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#define SR_INSERT (SR_WRITE | SR_DUPLAST | SR_PAST_EOF | SR_STACK)
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#define SR_KEYFIRST (SR_WRITE | SR_DUPFIRST | SR_PAST_EOF | SR_STACK)
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#define SR_KEYLAST (SR_WRITE | SR_DUPLAST | SR_PAST_EOF | SR_STACK)
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#define SR_WRPAIR (SR_WRITE | SR_DUPLAST | SR_PAST_EOF | SR_PARENT)
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/*
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* Various routines pass around page references. A page reference is
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* a pointer to the page, and the indx indicates an item on the page.
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* Each page reference may include a lock.
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*/
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struct __epg {
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PAGE *page; /* The page. */
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db_indx_t indx; /* The index on the page. */
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db_indx_t entries; /* The number of entries on page */
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DB_LOCK lock; /* The page's lock. */
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db_lockmode_t lock_mode; /* The lock mode. */
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};
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/*
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* We maintain a stack of the pages that we're locking in the tree. Grow
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* the stack as necessary.
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*
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* XXX
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* Temporary fix for #3243 -- clear the page and lock from the stack entry.
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* The correct fix is to never release a stack that doesn't hold items.
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*/
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#define BT_STK_CLR(c) do { \
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(c)->csp = (c)->sp; \
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(c)->csp->page = NULL; \
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LOCK_INIT((c)->csp->lock); \
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} while (0)
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#define BT_STK_ENTER(env, c, pagep, page_indx, l, mode, ret) do { \
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if ((ret = ((c)->csp == (c)->esp ? \
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__bam_stkgrow(env, c) : 0)) == 0) { \
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(c)->csp->page = pagep; \
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(c)->csp->indx = (page_indx); \
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(c)->csp->entries = NUM_ENT(pagep); \
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(c)->csp->lock = l; \
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(c)->csp->lock_mode = mode; \
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} \
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} while (0)
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#define BT_STK_PUSH(env, c, pagep, page_indx, lock, mode, ret) do { \
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BT_STK_ENTER(env, c, pagep, page_indx, lock, mode, ret); \
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++(c)->csp; \
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} while (0)
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#define BT_STK_NUM(env, c, pagep, page_indx, ret) do { \
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if ((ret = ((c)->csp == \
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(c)->esp ? __bam_stkgrow(env, c) : 0)) == 0) { \
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(c)->csp->page = NULL; \
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(c)->csp->indx = (page_indx); \
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(c)->csp->entries = NUM_ENT(pagep); \
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LOCK_INIT((c)->csp->lock); \
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(c)->csp->lock_mode = DB_LOCK_NG; \
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} \
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} while (0)
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#define BT_STK_NUMPUSH(env, c, pagep, page_indx, ret) do { \
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BT_STK_NUM(env, cp, pagep, page_indx, ret); \
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++(c)->csp; \
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} while (0)
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#define BT_STK_POP(c) \
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((c)->csp == (c)->sp ? NULL : --(c)->csp)
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/* Btree/Recno cursor. */
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struct __cursor {
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/* struct __dbc_internal */
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__DBC_INTERNAL
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/* btree private part */
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EPG *sp; /* Stack pointer. */
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EPG *csp; /* Current stack entry. */
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EPG *esp; /* End stack pointer. */
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EPG stack[5];
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db_indx_t ovflsize; /* Maximum key/data on-page size. */
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db_recno_t recno; /* Current record number. */
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u_int32_t order; /* Relative order among deleted curs. */
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/*
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* Btree:
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* We set a flag in the cursor structure if the underlying object has
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* been deleted. It's not strictly necessary, we could get the same
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* information by looking at the page itself, but this method doesn't
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* require us to retrieve the page on cursor delete.
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*
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* Recno:
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* When renumbering recno databases during deletes, cursors referencing
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* "deleted" records end up positioned between two records, and so must
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* be specially adjusted on the next operation.
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*/
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#define C_DELETED 0x0001 /* Record was deleted. */
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/*
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* There are three tree types that require maintaining record numbers.
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* Recno AM trees, Btree AM trees for which the DB_RECNUM flag was set,
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* and Btree off-page duplicate trees.
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*/
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#define C_RECNUM 0x0002 /* Tree requires record counts. */
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/*
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* Recno trees have immutable record numbers by default, but optionally
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* support mutable record numbers. Off-page duplicate Recno trees have
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* mutable record numbers. All Btrees with record numbers (including
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* off-page duplicate trees) are mutable by design, no flag is needed.
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*/
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#define C_RENUMBER 0x0004 /* Tree records are mutable. */
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u_int32_t flags;
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};
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/*
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* Threshhold value, as a function of bt_minkey, of the number of
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* bytes a key/data pair can use before being placed on an overflow
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* page. Assume every item requires the maximum alignment for
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* padding, out of sheer paranoia.
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*/
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#define B_MINKEY_TO_OVFLSIZE(dbp, minkey, pgsize) \
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((u_int16_t)(((pgsize) - P_OVERHEAD(dbp)) / ((minkey) * P_INDX) -\
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(BKEYDATA_PSIZE(0) + DB_ALIGN(1, sizeof(int32_t)))))
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/*
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* The maximum space that a single item can ever take up on one page.
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* Used by __bam_split to determine whether a split is still necessary.
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*/
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#define B_MAX(a,b) (((a) > (b)) ? (a) : (b))
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#define B_MAXSIZEONPAGE(ovflsize) \
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(B_MAX(BOVERFLOW_PSIZE, BKEYDATA_PSIZE(ovflsize)))
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/*
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* The in-memory, per-tree btree/recno data structure.
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*/
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struct __btree { /* Btree access method. */
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/*
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* !!!
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* These fields are write-once (when the structure is created) and
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* so are ignored as far as multi-threading is concerned.
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*/
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db_pgno_t bt_meta; /* Database meta-data page. */
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db_pgno_t bt_root; /* Database root page. */
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u_int32_t bt_minkey; /* Minimum keys per page. */
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/* Btree comparison function. */
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int (*bt_compare) __P((DB *, const DBT *, const DBT *));
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/* Btree prefix function. */
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size_t (*bt_prefix) __P((DB *, const DBT *, const DBT *));
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/* Recno access method. */
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int re_pad; /* Fixed-length padding byte. */
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int re_delim; /* Variable-length delimiting byte. */
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u_int32_t re_len; /* Length for fixed-length records. */
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char *re_source; /* Source file name. */
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/*
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* !!!
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* The bt_lpgno field is NOT protected by any mutex, and for this
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* reason must be advisory only, so, while it is read/written by
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* multiple threads, DB is completely indifferent to the quality
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* of its information.
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*/
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db_pgno_t bt_lpgno; /* Last insert location. */
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DB_LSN bt_llsn; /* Last insert LSN. */
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/*
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* !!!
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* The re_modified field is NOT protected by any mutex, and for this
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* reason cannot be anything more complicated than a zero/non-zero
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* value. The actual writing of the backing source file cannot be
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* threaded, so clearing the flag isn't a problem.
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*/
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int re_modified; /* If the tree was modified. */
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/*
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* !!!
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* These fields are ignored as far as multi-threading is concerned.
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* There are no transaction semantics associated with backing files,
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* nor is there any thread protection.
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*/
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FILE *re_fp; /* Source file handle. */
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int re_eof; /* Backing source file EOF reached. */
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db_recno_t re_last; /* Last record number read. */
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};
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/*
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* Modes for the __bam_curadj recovery records (btree_curadj).
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* These appear in log records, so we wire the values and
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* do not leave it up to the compiler.
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*/
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typedef enum {
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DB_CA_DI = 1,
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DB_CA_DUP = 2,
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DB_CA_RSPLIT = 3,
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DB_CA_SPLIT = 4
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} db_ca_mode;
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/*
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* Flags for __bam_pinsert.
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*/
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#define BPI_SPACEONLY 0x01 /* Only check for space to update. */
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#define BPI_NORECNUM 0x02 /* Not update the recnum on the left. */
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#if defined(__cplusplus)
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}
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#endif
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#include "dbinc_auto/btree_auto.h"
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#include "dbinc_auto/btree_ext.h"
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#include "dbinc/db_am.h"
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#endif /* !_DB_BTREE_H_ */
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