db_overflow.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996, 1997, 1998
* Sleepycat Software. All rights reserved.
*/
/*
* Copyright (c) 1990, 1993, 1994, 1995, 1996
* Keith Bostic. All rights reserved.
*/
/*
* Copyright (c) 1990, 1993, 1994, 1995
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Mike Olson.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "config.h"
#ifndef lint
static const char sccsid[] = "@(#)db_overflow.c 10.21 (Sleepycat) 9/27/98";
#endif /* not lint */
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <errno.h>
#include <string.h>
#endif
#include "db_int.h"
#include "db_page.h"
#include "db_am.h"
#include "common_ext.h"
/*
* Big key/data code.
*
* Big key and data entries are stored on linked lists of pages. The initial
* reference is a structure with the total length of the item and the page
* number where it begins. Each entry in the linked list contains a pointer
* to the next page of data, and so on.
*/
/*
* __db_goff --
* Get an offpage item.
*
* PUBLIC: int __db_goff __P((DB *, DBT *,
* PUBLIC: u_int32_t, db_pgno_t, void **, u_int32_t *));
*/
int
__db_goff(dbp, dbt, tlen, pgno, bpp, bpsz)
DB *dbp;
DBT *dbt;
u_int32_t tlen;
db_pgno_t pgno;
void **bpp;
u_int32_t *bpsz;
{
PAGE *h;
db_indx_t bytes;
u_int32_t curoff, needed, start;
u_int8_t *p, *src;
int ret;
/*
* Check if the buffer is big enough; if it is not and we are
* allowed to malloc space, then we'll malloc it. If we are
* not (DB_DBT_USERMEM), then we'll set the dbt and return
* appropriately.
*/
if (F_ISSET(dbt, DB_DBT_PARTIAL)) {
start = dbt->doff;
needed = dbt->dlen;
} else {
start = 0;
needed = tlen;
}
/* Allocate any necessary memory. */
if (F_ISSET(dbt, DB_DBT_USERMEM)) {
if (needed > dbt->ulen) {
dbt->size = needed;
return (ENOMEM);
}
} else if (F_ISSET(dbt, DB_DBT_MALLOC)) {
if ((ret =
__os_malloc(needed, dbp->db_malloc, &dbt->data)) != 0)
return (ret);
} else if (*bpsz == 0 || *bpsz < needed) {
if ((ret = __os_realloc(bpp, needed)) != 0)
return (ret);
*bpsz = needed;
dbt->data = *bpp;
} else
dbt->data = *bpp;
/*
* Step through the linked list of pages, copying the data on each
* one into the buffer. Never copy more than the total data length.
*/
dbt->size = needed;
for (curoff = 0, p = dbt->data; pgno != P_INVALID && needed > 0;) {
if ((ret = memp_fget(dbp->mpf, &pgno, 0, &h)) != 0) {
(void)__db_pgerr(dbp, pgno);
return (ret);
}
/* Check if we need any bytes from this page. */
if (curoff + OV_LEN(h) >= start) {
src = (u_int8_t *)h + P_OVERHEAD;
bytes = OV_LEN(h);
if (start > curoff) {
src += start - curoff;
bytes -= start - curoff;
}
if (bytes > needed)
bytes = needed;
memcpy(p, src, bytes);
p += bytes;
needed -= bytes;
}
curoff += OV_LEN(h);
pgno = h->next_pgno;
memp_fput(dbp->mpf, h, 0);
}
return (0);
}
/*
* __db_poff --
* Put an offpage item.
*
* PUBLIC: int __db_poff __P((DBC *, const DBT *, db_pgno_t *,
* PUBLIC: int (*)(DBC *, u_int32_t, PAGE **)));
*/
int
__db_poff(dbc, dbt, pgnop, newfunc)
DBC *dbc;
const DBT *dbt;
db_pgno_t *pgnop;
int (*newfunc) __P((DBC *, u_int32_t, PAGE **));
{
DB *dbp;
PAGE *pagep, *lastp;
DB_LSN new_lsn, null_lsn;
DBT tmp_dbt;
db_indx_t pagespace;
u_int32_t sz;
u_int8_t *p;
int ret;
/*
* Allocate pages and copy the key/data item into them. Calculate the
* number of bytes we get for pages we fill completely with a single
* item.
*/
dbp = dbc->dbp;
pagespace = P_MAXSPACE(dbp->pgsize);
lastp = NULL;
for (p = dbt->data,
sz = dbt->size; sz > 0; p += pagespace, sz -= pagespace) {
/*
* Reduce pagespace so we terminate the loop correctly and
* don't copy too much data.
*/
if (sz < pagespace)
pagespace = sz;
/*
* Allocate and initialize a new page and copy all or part of
* the item onto the page. If sz is less than pagespace, we
* have a partial record.
*/
if ((ret = newfunc(dbc, P_OVERFLOW, &pagep)) != 0)
return (ret);
if (DB_LOGGING(dbc)) {
tmp_dbt.data = p;
tmp_dbt.size = pagespace;
ZERO_LSN(null_lsn);
if ((ret = __db_big_log(dbp->dbenv->lg_info, dbc->txn,
&new_lsn, 0, DB_ADD_BIG, dbp->log_fileid,
PGNO(pagep), lastp ? PGNO(lastp) : PGNO_INVALID,
PGNO_INVALID, &tmp_dbt, &LSN(pagep),
lastp == NULL ? &null_lsn : &LSN(lastp),
&null_lsn)) != 0)
return (ret);
/* Move lsn onto page. */
if (lastp)
LSN(lastp) = new_lsn;
LSN(pagep) = new_lsn;
}
P_INIT(pagep, dbp->pgsize,
PGNO(pagep), PGNO_INVALID, PGNO_INVALID, 0, P_OVERFLOW);
OV_LEN(pagep) = pagespace;
OV_REF(pagep) = 1;
memcpy((u_int8_t *)pagep + P_OVERHEAD, p, pagespace);
/*
* If this is the first entry, update the user's info.
* Otherwise, update the entry on the last page filled
* in and release that page.
*/
if (lastp == NULL)
*pgnop = PGNO(pagep);
else {
lastp->next_pgno = PGNO(pagep);
pagep->prev_pgno = PGNO(lastp);
(void)memp_fput(dbp->mpf, lastp, DB_MPOOL_DIRTY);
}
lastp = pagep;
}
(void)memp_fput(dbp->mpf, lastp, DB_MPOOL_DIRTY);
return (0);
}
/*
* __db_ovref --
* Increment/decrement the reference count on an overflow page.
*
* PUBLIC: int __db_ovref __P((DBC *, db_pgno_t, int32_t));
*/
int
__db_ovref(dbc, pgno, adjust)
DBC *dbc;
db_pgno_t pgno;
int32_t adjust;
{
DB *dbp;
PAGE *h;
int ret;
dbp = dbc->dbp;
if ((ret = memp_fget(dbp->mpf, &pgno, 0, &h)) != 0) {
(void)__db_pgerr(dbp, pgno);
return (ret);
}
if (DB_LOGGING(dbc))
if ((ret = __db_ovref_log(dbp->dbenv->lg_info, dbc->txn,
&LSN(h), 0, dbp->log_fileid, h->pgno, adjust,
&LSN(h))) != 0)
return (ret);
OV_REF(h) += adjust;
(void)memp_fput(dbp->mpf, h, DB_MPOOL_DIRTY);
return (0);
}
/*
* __db_doff --
* Delete an offpage chain of overflow pages.
*
* PUBLIC: int __db_doff __P((DBC *, db_pgno_t, int (*)(DBC *, PAGE *)));
*/
int
__db_doff(dbc, pgno, freefunc)
DBC *dbc;
db_pgno_t pgno;
int (*freefunc) __P((DBC *, PAGE *));
{
DB *dbp;
PAGE *pagep;
DB_LSN null_lsn;
DBT tmp_dbt;
int ret;
dbp = dbc->dbp;
do {
if ((ret = memp_fget(dbp->mpf, &pgno, 0, &pagep)) != 0) {
(void)__db_pgerr(dbp, pgno);
return (ret);
}
/*
* If it's an overflow page and it's referenced by more than
* one key/data item, decrement the reference count and return.
*/
if (TYPE(pagep) == P_OVERFLOW && OV_REF(pagep) > 1) {
(void)memp_fput(dbp->mpf, pagep, 0);
return (__db_ovref(dbc, pgno, -1));
}
if (DB_LOGGING(dbc)) {
tmp_dbt.data = (u_int8_t *)pagep + P_OVERHEAD;
tmp_dbt.size = OV_LEN(pagep);
ZERO_LSN(null_lsn);
if ((ret = __db_big_log(dbp->dbenv->lg_info, dbc->txn,
&LSN(pagep), 0, DB_REM_BIG, dbp->log_fileid,
PGNO(pagep), PREV_PGNO(pagep), NEXT_PGNO(pagep),
&tmp_dbt, &LSN(pagep), &null_lsn, &null_lsn)) != 0)
return (ret);
}
pgno = pagep->next_pgno;
if ((ret = freefunc(dbc, pagep)) != 0)
return (ret);
} while (pgno != PGNO_INVALID);
return (0);
}
/*
* __db_moff --
* Match on overflow pages.
*
* Given a starting page number and a key, return <0, 0, >0 to indicate if the
* key on the page is less than, equal to or greater than the key specified.
* We optimize this by doing chunk at a time comparison unless the user has
* specified a comparison function. In this case, we need to materialize
* the entire object and call their comparison routine.
*
* PUBLIC: int __db_moff __P((DB *, const DBT *, db_pgno_t, u_int32_t,
* PUBLIC: int (*)(const DBT *, const DBT *), int *));
*/
int
__db_moff(dbp, dbt, pgno, tlen, cmpfunc, cmpp)
DB *dbp;
const DBT *dbt;
db_pgno_t pgno;
u_int32_t tlen;
int (*cmpfunc) __P((const DBT *, const DBT *)), *cmpp;
{
PAGE *pagep;
DBT local_dbt;
void *buf;
u_int32_t bufsize, cmp_bytes, key_left;
u_int8_t *p1, *p2;
int ret;
/*
* If there is a user-specified comparison function, build a
* contiguous copy of the key, and call it.
*/
if (cmpfunc != NULL) {
memset(&local_dbt, 0, sizeof(local_dbt));
buf = NULL;
bufsize = 0;
if ((ret = __db_goff(dbp,
&local_dbt, tlen, pgno, &buf, &bufsize)) != 0)
return (ret);
*cmpp = cmpfunc(&local_dbt, dbt);
__os_free(buf, bufsize);
return (0);
}
/* While there are both keys to compare. */
for (*cmpp = 0, p1 = dbt->data,
key_left = dbt->size; key_left > 0 && pgno != PGNO_INVALID;) {
if ((ret = memp_fget(dbp->mpf, &pgno, 0, &pagep)) != 0)
return (ret);
cmp_bytes = OV_LEN(pagep) < key_left ? OV_LEN(pagep) : key_left;
key_left -= cmp_bytes;
for (p2 =
(u_int8_t *)pagep + P_OVERHEAD; cmp_bytes-- > 0; ++p1, ++p2)
if (*p1 != *p2) {
*cmpp = (long)*p1 - (long)*p2;
break;
}
pgno = NEXT_PGNO(pagep);
if ((ret = memp_fput(dbp->mpf, pagep, 0)) != 0)
return (ret);
if (*cmpp != 0)
return (0);
}
if (key_left > 0) /* DBT is longer than page key. */
*cmpp = -1;
else if (pgno != PGNO_INVALID) /* DBT is shorter than page key. */
*cmpp = 1;
else
*cmpp = 0;
return (0);
}