db_dup.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996, 1997, 1998
* Sleepycat Software. All rights reserved.
*/
#include "config.h"
#ifndef lint
static const char sccsid[] = "@(#)db_dup.c 10.35 (Sleepycat) 12/2/98";
#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 "btree.h"
#include "db_am.h"
static int __db_addpage __P((DBC *,
PAGE **, db_indx_t *, int (*)(DBC *, u_int32_t, PAGE **)));
static int __db_dsplit __P((DBC *,
PAGE **, db_indx_t *, u_int32_t, int (*)(DBC *, u_int32_t, PAGE **)));
/*
* __db_dput --
* Put a duplicate item onto a duplicate page at the given index.
*
* PUBLIC: int __db_dput __P((DBC *, DBT *,
* PUBLIC: PAGE **, db_indx_t *, int (*)(DBC *, u_int32_t, PAGE **)));
*/
int
__db_dput(dbc, dbt, pp, indxp, newfunc)
DBC *dbc;
DBT *dbt;
PAGE **pp;
db_indx_t *indxp;
int (*newfunc) __P((DBC *, u_int32_t, PAGE **));
{
BOVERFLOW bo;
DBT *data_dbtp, hdr_dbt, *hdr_dbtp;
PAGE *pagep;
db_indx_t size, isize;
db_pgno_t pgno;
int ret;
/*
* We need some access method independent threshold for when we put
* a duplicate item onto an overflow page.
*/
if (dbt->size > 0.25 * dbc->dbp->pgsize) {
if ((ret = __db_poff(dbc, dbt, &pgno, newfunc)) != 0)
return (ret);
UMRW(bo.unused1);
B_TSET(bo.type, B_OVERFLOW, 0);
UMRW(bo.unused2);
bo.tlen = dbt->size;
bo.pgno = pgno;
hdr_dbt.data = &bo;
hdr_dbt.size = isize = BOVERFLOW_SIZE;
hdr_dbtp = &hdr_dbt;
size = BOVERFLOW_PSIZE;
data_dbtp = NULL;
} else {
size = BKEYDATA_PSIZE(dbt->size);
isize = BKEYDATA_SIZE(dbt->size);
hdr_dbtp = NULL;
data_dbtp = dbt;
}
pagep = *pp;
if (size > P_FREESPACE(pagep)) {
if (*indxp == NUM_ENT(*pp) && NEXT_PGNO(*pp) == PGNO_INVALID)
ret = __db_addpage(dbc, pp, indxp, newfunc);
else
ret = __db_dsplit(dbc, pp, indxp, isize, newfunc);
if (ret != 0)
/*
* XXX
* Pages not returned to free list.
*/
return (ret);
pagep = *pp;
}
/*
* Now, pagep references the page on which to insert and indx is the
* the location to insert.
*/
if ((ret = __db_pitem(dbc,
pagep, (u_int32_t)*indxp, isize, hdr_dbtp, data_dbtp)) != 0)
return (ret);
(void)memp_fset(dbc->dbp->mpf, pagep, DB_MPOOL_DIRTY);
return (0);
}
/*
* __db_drem --
* Remove a duplicate at the given index on the given page.
*
* PUBLIC: int __db_drem __P((DBC *,
* PUBLIC: PAGE **, u_int32_t, int (*)(DBC *, PAGE *)));
*/
int
__db_drem(dbc, pp, indx, freefunc)
DBC *dbc;
PAGE **pp;
u_int32_t indx;
int (*freefunc) __P((DBC *, PAGE *));
{
PAGE *pagep;
int ret;
pagep = *pp;
/* Check if we are freeing a big item. */
if (B_TYPE(GET_BKEYDATA(pagep, indx)->type) == B_OVERFLOW) {
if ((ret = __db_doff(dbc,
GET_BOVERFLOW(pagep, indx)->pgno, freefunc)) != 0)
return (ret);
ret = __db_ditem(dbc, pagep, indx, BOVERFLOW_SIZE);
} else
ret = __db_ditem(dbc, pagep, indx,
BKEYDATA_SIZE(GET_BKEYDATA(pagep, indx)->len));
if (ret != 0)
return (ret);
if (NUM_ENT(pagep) == 0) {
/*
* If the page is emptied, then the page is freed and the pp
* parameter is set to reference the next, locked page in the
* duplicate chain, if one exists. If there was no such page,
* then it is set to NULL.
*
* !!!
* __db_relink will set the dirty bit for us.
*/
if ((ret = __db_relink(dbc, DB_REM_PAGE, pagep, pp, 0)) != 0)
return (ret);
if ((ret = freefunc(dbc, pagep)) != 0)
return (ret);
} else
(void)memp_fset(dbc->dbp->mpf, pagep, DB_MPOOL_DIRTY);
return (0);
}
/*
* __db_dend --
* Find the last page in a set of offpage duplicates.
*
* PUBLIC: int __db_dend __P((DBC *, db_pgno_t, PAGE **));
*/
int
__db_dend(dbc, pgno, pp)
DBC *dbc;
db_pgno_t pgno;
PAGE **pp;
{
DB *dbp;
PAGE *h;
int ret;
dbp = dbc->dbp;
/*
* This implements DB_KEYLAST. The last page is returned in pp; pgno
* should be the page number of the first page of the duplicate chain.
*
* *pp may be non-NULL -- if given a valid page use it.
*/
if (*pp != NULL)
goto started;
for (;;) {
if ((ret = memp_fget(dbp->mpf, &pgno, 0, pp)) != 0) {
(void)__db_pgerr(dbp, pgno);
return (ret);
}
started: h = *pp;
if ((pgno = NEXT_PGNO(h)) == PGNO_INVALID)
break;
if ((ret = memp_fput(dbp->mpf, h, 0)) != 0)
return (ret);
}
return (0);
}
/*
* __db_dsplit --
* Split a page of duplicates, calculating the split point based
* on an element of size "size" being added at "*indxp".
* On entry hp contains a pointer to the page-pointer of the original
* page. On exit, it returns a pointer to the page containing "*indxp"
* and "indxp" has been modified to reflect the index on the new page
* where the element should be added. The function returns with
* the page on which the insert should happen, not yet put.
*/
static int
__db_dsplit(dbc, hp, indxp, size, newfunc)
DBC *dbc;
PAGE **hp;
db_indx_t *indxp;
u_int32_t size;
int (*newfunc) __P((DBC *, u_int32_t, PAGE **));
{
PAGE *h, *np, *tp;
BKEYDATA *bk;
DBT page_dbt;
DB *dbp;
size_t pgsize;
db_indx_t halfbytes, i, indx, lastsum, nindex, oindex, s, sum;
int did_indx, ret, t_ret;
h = *hp;
indx = *indxp;
ret = 0;
dbp = dbc->dbp;
pgsize = dbp->pgsize;
/* Create a temporary page to do compaction onto. */
if ((ret = __os_malloc(pgsize, NULL, &tp)) != 0)
return (ret);
/* Create new page for the split. */
if ((ret = newfunc(dbc, P_DUPLICATE, &np)) != 0) {
__os_free(tp, pgsize);
return (ret);
}
P_INIT(np, pgsize, PGNO(np), PGNO(h), NEXT_PGNO(h), 0,
P_DUPLICATE);
P_INIT(tp, pgsize, PGNO(h), PREV_PGNO(h), PGNO(np), 0,
P_DUPLICATE);
/* Figure out the split point */
halfbytes = (pgsize - HOFFSET(h)) / 2;
did_indx = 0;
for (sum = 0, lastsum = 0, i = 0; i < NUM_ENT(h); i++) {
if (i == indx) {
sum += size;
did_indx = 1;
if (lastsum < halfbytes && sum >= halfbytes) {
/* We've crossed the halfway point. */
if ((db_indx_t)(halfbytes - lastsum) <
(db_indx_t)(sum - halfbytes)) {
*hp = np;
*indxp = 0;
} else
*indxp = i;
break;
}
*indxp = i;
lastsum = sum;
}
if (B_TYPE(GET_BKEYDATA(h, i)->type) == B_KEYDATA)
sum += BKEYDATA_SIZE(GET_BKEYDATA(h, i)->len);
else
sum += BOVERFLOW_SIZE;
if (lastsum < halfbytes && sum >= halfbytes) {
/* We've crossed the halfway point. */
if ((db_indx_t)(sum - halfbytes) <
(db_indx_t)(halfbytes - lastsum))
i++;
break;
}
}
/*
* Check if we have set the return values of the index pointer and
* page pointer.
*/
if (!did_indx) {
*hp = np;
*indxp = indx - i;
}
if (DB_LOGGING(dbc)) {
page_dbt.size = dbp->pgsize;
page_dbt.data = h;
if ((ret = __db_split_log(dbp->dbenv->lg_info,
dbc->txn, &LSN(h), 0, DB_SPLITOLD, dbp->log_fileid,
PGNO(h), &page_dbt, &LSN(h))) != 0) {
__os_free(tp, pgsize);
return (ret);
}
LSN(tp) = LSN(h);
}
/*
* If it's a btree, adjust the cursors.
*
* i is the index of the first element to move onto the new page.
*/
if (dbp->type == DB_BTREE)
__bam_ca_split(dbp, PGNO(h), PGNO(h), PGNO(np), i, 0);
for (nindex = 0, oindex = i; oindex < NUM_ENT(h); oindex++) {
bk = GET_BKEYDATA(h, oindex);
if (B_TYPE(bk->type) == B_KEYDATA)
s = BKEYDATA_SIZE(bk->len);
else
s = BOVERFLOW_SIZE;
np->inp[nindex++] = HOFFSET(np) -= s;
memcpy((u_int8_t *)np + HOFFSET(np), bk, s);
NUM_ENT(np)++;
}
/*
* Now do data compaction by copying the remaining stuff onto the
* temporary page and then copying it back to the real page.
*/
for (nindex = 0, oindex = 0; oindex < i; oindex++) {
bk = GET_BKEYDATA(h, oindex);
if (B_TYPE(bk->type) == B_KEYDATA)
s = BKEYDATA_SIZE(bk->len);
else
s = BOVERFLOW_SIZE;
tp->inp[nindex++] = HOFFSET(tp) -= s;
memcpy((u_int8_t *)tp + HOFFSET(tp), bk, s);
NUM_ENT(tp)++;
}
/*
* This page (the temporary) should be only half full, so we do two
* memcpy's, one for the top of the page and one for the bottom of
* the page. This way we avoid copying the middle which should be
* about half a page.
*/
memcpy(h, tp, LOFFSET(tp));
memcpy((u_int8_t *)h + HOFFSET(tp),
(u_int8_t *)tp + HOFFSET(tp), pgsize - HOFFSET(tp));
__os_free(tp, pgsize);
if (DB_LOGGING(dbc)) {
/*
* XXX
* If either of these fails, are we leaving pages pinned?
* Yes, but it seems like this happens in error case.
*/
page_dbt.size = pgsize;
page_dbt.data = h;
if ((ret = __db_split_log(dbp->dbenv->lg_info,
dbc->txn, &LSN(h), 0, DB_SPLITNEW, dbp->log_fileid,
PGNO(h), &page_dbt, &LSN(h))) != 0)
return (ret);
page_dbt.size = pgsize;
page_dbt.data = np;
if ((ret = __db_split_log(dbp->dbenv->lg_info,
dbc->txn, &LSN(np), 0, DB_SPLITNEW, dbp->log_fileid,
PGNO(np), &page_dbt, &LSN(np))) != 0)
return (ret);
}
/*
* Finally, if there was a next page after the page being
* split, fix its prev pointer.
*/
if (np->next_pgno != PGNO_INVALID)
ret = __db_relink(dbc, DB_ADD_PAGE, np, NULL, 1);
/*
* Figure out if the location we're interested in is on the new
* page, and if so, reset the callers' pointer. Push the other
* page back to the store.
*/
if (*hp == h)
t_ret = memp_fput(dbp->mpf, np, DB_MPOOL_DIRTY);
else
t_ret = memp_fput(dbp->mpf, h, DB_MPOOL_DIRTY);
return (ret != 0 ? ret : t_ret);
}
/*
* __db_ditem --
* Remove an item from a page.
*
* PUBLIC: int __db_ditem __P((DBC *, PAGE *, u_int32_t, u_int32_t));
*/
int
__db_ditem(dbc, pagep, indx, nbytes)
DBC *dbc;
PAGE *pagep;
u_int32_t indx, nbytes;
{
DB *dbp;
DBT ldbt;
db_indx_t cnt, offset;
int ret;
u_int8_t *from;
dbp = dbc->dbp;
if (DB_LOGGING(dbc)) {
ldbt.data = P_ENTRY(pagep, indx);
ldbt.size = nbytes;
if ((ret = __db_addrem_log(dbp->dbenv->lg_info, dbc->txn,
&LSN(pagep), 0, DB_REM_DUP, dbp->log_fileid, PGNO(pagep),
(u_int32_t)indx, nbytes, &ldbt, NULL, &LSN(pagep))) != 0)
return (ret);
}
/*
* If there's only a single item on the page, we don't have to
* work hard.
*/
if (NUM_ENT(pagep) == 1) {
NUM_ENT(pagep) = 0;
HOFFSET(pagep) = dbp->pgsize;
return (0);
}
/*
* Pack the remaining key/data items at the end of the page. Use
* memmove(3), the regions may overlap.
*/
from = (u_int8_t *)pagep + HOFFSET(pagep);
memmove(from + nbytes, from, pagep->inp[indx] - HOFFSET(pagep));
HOFFSET(pagep) += nbytes;
/* Adjust the indices' offsets. */
offset = pagep->inp[indx];
for (cnt = 0; cnt < NUM_ENT(pagep); ++cnt)
if (pagep->inp[cnt] < offset)
pagep->inp[cnt] += nbytes;
/* Shift the indices down. */
--NUM_ENT(pagep);
if (indx != NUM_ENT(pagep))
memmove(&pagep->inp[indx], &pagep->inp[indx + 1],
sizeof(db_indx_t) * (NUM_ENT(pagep) - indx));
/* If it's a btree, adjust the cursors. */
if (dbp->type == DB_BTREE)
__bam_ca_di(dbp, PGNO(pagep), indx, -1);
return (0);
}
/*
* __db_pitem --
* Put an item on a page.
*
* PUBLIC: int __db_pitem
* PUBLIC: __P((DBC *, PAGE *, u_int32_t, u_int32_t, DBT *, DBT *));
*/
int
__db_pitem(dbc, pagep, indx, nbytes, hdr, data)
DBC *dbc;
PAGE *pagep;
u_int32_t indx;
u_int32_t nbytes;
DBT *hdr, *data;
{
DB *dbp;
BKEYDATA bk;
DBT thdr;
int ret;
u_int8_t *p;
/*
* Put a single item onto a page. The logic figuring out where to
* insert and whether it fits is handled in the caller. All we do
* here is manage the page shuffling. We cheat a little bit in that
* we don't want to copy the dbt on a normal put twice. If hdr is
* NULL, we create a BKEYDATA structure on the page, otherwise, just
* copy the caller's information onto the page.
*
* This routine is also used to put entries onto the page where the
* entry is pre-built, e.g., during recovery. In this case, the hdr
* will point to the entry, and the data argument will be NULL.
*
* !!!
* There's a tremendous potential for off-by-one errors here, since
* the passed in header sizes must be adjusted for the structure's
* placeholder for the trailing variable-length data field.
*/
dbp = dbc->dbp;
if (DB_LOGGING(dbc))
if ((ret = __db_addrem_log(dbp->dbenv->lg_info, dbc->txn,
&LSN(pagep), 0, DB_ADD_DUP, dbp->log_fileid, PGNO(pagep),
(u_int32_t)indx, nbytes, hdr, data, &LSN(pagep))) != 0)
return (ret);
if (hdr == NULL) {
B_TSET(bk.type, B_KEYDATA, 0);
bk.len = data == NULL ? 0 : data->size;
thdr.data = &bk;
thdr.size = SSZA(BKEYDATA, data);
hdr = &thdr;
}
/* Adjust the index table, then put the item on the page. */
if (indx != NUM_ENT(pagep))
memmove(&pagep->inp[indx + 1], &pagep->inp[indx],
sizeof(db_indx_t) * (NUM_ENT(pagep) - indx));
HOFFSET(pagep) -= nbytes;
pagep->inp[indx] = HOFFSET(pagep);
++NUM_ENT(pagep);
p = P_ENTRY(pagep, indx);
memcpy(p, hdr->data, hdr->size);
if (data != NULL)
memcpy(p + hdr->size, data->data, data->size);
/* If it's a btree, adjust the cursors. */
if (dbp->type == DB_BTREE)
__bam_ca_di(dbp, PGNO(pagep), indx, 1);
return (0);
}
/*
* __db_relink --
* Relink around a deleted page.
*
* PUBLIC: int __db_relink __P((DBC *, u_int32_t, PAGE *, PAGE **, int));
*/
int
__db_relink(dbc, add_rem, pagep, new_next, needlock)
DBC *dbc;
u_int32_t add_rem;
PAGE *pagep, **new_next;
int needlock;
{
DB *dbp;
PAGE *np, *pp;
DB_LOCK npl, ppl;
DB_LSN *nlsnp, *plsnp;
int ret;
ret = 0;
np = pp = NULL;
npl = ppl = LOCK_INVALID;
nlsnp = plsnp = NULL;
dbp = dbc->dbp;
/*
* Retrieve and lock the one/two pages. For a remove, we may need
* two pages (the before and after). For an add, we only need one
* because, the split took care of the prev.
*/
if (pagep->next_pgno != PGNO_INVALID) {
if (needlock && (ret = __bam_lget(dbc,
0, pagep->next_pgno, DB_LOCK_WRITE, &npl)) != 0)
goto err;
if ((ret = memp_fget(dbp->mpf,
&pagep->next_pgno, 0, &np)) != 0) {
(void)__db_pgerr(dbp, pagep->next_pgno);
goto err;
}
nlsnp = &np->lsn;
}
if (add_rem == DB_REM_PAGE && pagep->prev_pgno != PGNO_INVALID) {
if (needlock && (ret = __bam_lget(dbc,
0, pagep->prev_pgno, DB_LOCK_WRITE, &ppl)) != 0)
goto err;
if ((ret = memp_fget(dbp->mpf,
&pagep->prev_pgno, 0, &pp)) != 0) {
(void)__db_pgerr(dbp, pagep->next_pgno);
goto err;
}
plsnp = &pp->lsn;
}
/* Log the change. */
if (DB_LOGGING(dbc)) {
if ((ret = __db_relink_log(dbp->dbenv->lg_info, dbc->txn,
&pagep->lsn, 0, add_rem, dbp->log_fileid,
pagep->pgno, &pagep->lsn,
pagep->prev_pgno, plsnp, pagep->next_pgno, nlsnp)) != 0)
goto err;
if (np != NULL)
np->lsn = pagep->lsn;
if (pp != NULL)
pp->lsn = pagep->lsn;
}
/*
* Modify and release the two pages.
*
* !!!
* The parameter new_next gets set to the page following the page we
* are removing. If there is no following page, then new_next gets
* set to NULL.
*/
if (np != NULL) {
if (add_rem == DB_ADD_PAGE)
np->prev_pgno = pagep->pgno;
else
np->prev_pgno = pagep->prev_pgno;
if (new_next == NULL)
ret = memp_fput(dbp->mpf, np, DB_MPOOL_DIRTY);
else {
*new_next = np;
ret = memp_fset(dbp->mpf, np, DB_MPOOL_DIRTY);
}
if (ret != 0)
goto err;
if (needlock)
(void)__bam_lput(dbc, npl);
} else if (new_next != NULL)
*new_next = NULL;
if (pp != NULL) {
pp->next_pgno = pagep->next_pgno;
if ((ret = memp_fput(dbp->mpf, pp, DB_MPOOL_DIRTY)) != 0)
goto err;
if (needlock)
(void)__bam_lput(dbc, ppl);
}
return (0);
err: if (np != NULL)
(void)memp_fput(dbp->mpf, np, 0);
if (needlock && npl != LOCK_INVALID)
(void)__bam_lput(dbc, npl);
if (pp != NULL)
(void)memp_fput(dbp->mpf, pp, 0);
if (needlock && ppl != LOCK_INVALID)
(void)__bam_lput(dbc, ppl);
return (ret);
}
/*
* __db_ddup --
* Delete an offpage chain of duplicates.
*
* PUBLIC: int __db_ddup __P((DBC *, db_pgno_t, int (*)(DBC *, PAGE *)));
*/
int
__db_ddup(dbc, pgno, freefunc)
DBC *dbc;
db_pgno_t pgno;
int (*freefunc) __P((DBC *, PAGE *));
{
DB *dbp;
PAGE *pagep;
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 (DB_LOGGING(dbc)) {
tmp_dbt.data = pagep;
tmp_dbt.size = dbp->pgsize;
if ((ret = __db_split_log(dbp->dbenv->lg_info,
dbc->txn, &LSN(pagep), 0, DB_SPLITOLD,
dbp->log_fileid, PGNO(pagep), &tmp_dbt,
&LSN(pagep))) != 0)
return (ret);
}
pgno = pagep->next_pgno;
if ((ret = freefunc(dbc, pagep)) != 0)
return (ret);
} while (pgno != PGNO_INVALID);
return (0);
}
/*
* __db_addpage --
* Create a new page and link it onto the next_pgno field of the
* current page.
*/
static int
__db_addpage(dbc, hp, indxp, newfunc)
DBC *dbc;
PAGE **hp;
db_indx_t *indxp;
int (*newfunc) __P((DBC *, u_int32_t, PAGE **));
{
DB *dbp;
PAGE *newpage;
int ret;
dbp = dbc->dbp;
if ((ret = newfunc(dbc, P_DUPLICATE, &newpage)) != 0)
return (ret);
if (DB_LOGGING(dbc)) {
if ((ret = __db_addpage_log(dbp->dbenv->lg_info,
dbc->txn, &LSN(*hp), 0, dbp->log_fileid,
PGNO(*hp), &LSN(*hp), PGNO(newpage), &LSN(newpage))) != 0) {
return (ret);
}
LSN(newpage) = LSN(*hp);
}
PREV_PGNO(newpage) = PGNO(*hp);
NEXT_PGNO(*hp) = PGNO(newpage);
if ((ret = memp_fput(dbp->mpf, *hp, DB_MPOOL_DIRTY)) != 0)
return (ret);
*hp = newpage;
*indxp = 0;
return (0);
}
/*
* __db_dsearch --
* Search a set of duplicates for the proper position for a new duplicate.
*
* + pgno is the page number of the page on which to begin searching.
* Since we can continue duplicate searches, it might not be the first
* page.
*
* + If we are continuing a search, then *pp may be non-NULL in which
* case we do not have to retrieve the page.
*
* + If we are continuing a search, then *indxp contains the first
* on pgno of where we should begin the search.
*
* NOTE: if there is no comparison function, then continuing is
* meaningless, and *pp should always be NULL and *indxp will be
* ignored.
*
* 3 return values::
*
* + pp is the returned page pointer of where this element should go.
* + indxp is the returned index on that page
* + cmpp is the returned final comparison result.
*
* PUBLIC: int __db_dsearch __P((DBC *,
* PUBLIC: int, DBT *, db_pgno_t, db_indx_t *, PAGE **, int *));
*/
int
__db_dsearch(dbc, is_insert, dbt, pgno, indxp, pp, cmpp)
DBC *dbc;
int is_insert, *cmpp;
DBT *dbt;
db_pgno_t pgno;
db_indx_t *indxp;
PAGE **pp;
{
DB *dbp;
PAGE *h;
db_indx_t base, indx, lim, save_indx;
db_pgno_t save_pgno;
int ret;
dbp = dbc->dbp;
if (dbp->dup_compare == NULL) {
/*
* We may have been given a valid page, but we may not be
* able to use it. The problem is that the application is
* doing a join and we're trying to continue the search,
* but since the items aren't sorted, we can't. Discard
* the page if it's not the one we're going to start with
* anyway.
*/
if (*pp != NULL && (*pp)->pgno != pgno) {
if ((ret = memp_fput(dbp->mpf, *pp, 0)) != 0)
return (ret);
*pp = NULL;
}
/*
* If no duplicate function is specified, just go to the end
* of the duplicate set.
*/
if (is_insert) {
if ((ret = __db_dend(dbc, pgno, pp)) != 0)
return (ret);
*indxp = NUM_ENT(*pp);
return (0);
}
/*
* We are looking for a specific duplicate, so do a linear
* search.
*/
if (*pp != NULL)
goto nocmp_started;
for (;;) {
if ((ret = memp_fget(dbp->mpf, &pgno, 0, pp)) != 0)
goto pg_err;
nocmp_started: h = *pp;
for (*indxp = 0; *indxp < NUM_ENT(h); ++*indxp) {
if ((*cmpp = __bam_cmp(dbp,
dbt, h, *indxp, __bam_defcmp)) != 0)
continue;
/*
* The duplicate may have already been deleted,
* if it's a btree page, in which case we skip
* it.
*/
if (dbp->type == DB_BTREE &&
B_DISSET(GET_BKEYDATA(h, *indxp)->type))
continue;
return (0);
}
if ((pgno = h->next_pgno) == PGNO_INVALID)
break;
if ((ret = memp_fput(dbp->mpf, h, 0)) != 0)
return (ret);
}
*cmpp = 1; /* We didn't succeed... */
return (0);
}
/*
* We have a comparison routine, i.e., the duplicates are sorted.
* Walk through the chain of duplicates, checking the last entry
* on each page to decide if it's the page we want to search.
*
* *pp may be non-NULL -- if we were given a valid page (e.g., are
* in mid-search), then use the provided page.
*/
if (*pp != NULL)
goto cmp_started;
for (;;) {
if ((ret = memp_fget(dbp->mpf, &pgno, 0, pp)) != 0)
goto pg_err;
cmp_started: h = *pp;
if ((pgno = h->next_pgno) == PGNO_INVALID || __bam_cmp(dbp,
dbt, h, h->entries - 1, dbp->dup_compare) <= 0)
break;
/*
* Even when continuing a search, make sure we don't skip
* entries on a new page
*/
*indxp = 0;
if ((ret = memp_fput(dbp->mpf, h, 0)) != 0)
return (ret);
}
/* Next, do a binary search on the page. */
base = F_ISSET(dbc, DBC_CONTINUE) ? *indxp : 0;
for (lim = NUM_ENT(h) - base; lim != 0; lim >>= 1) {
indx = base + (lim >> 1);
if ((*cmpp = __bam_cmp(dbp,
dbt, h, indx, dbp->dup_compare)) == 0) {
*indxp = indx;
if (dbp->type != DB_BTREE ||
!B_DISSET(GET_BKEYDATA(h, *indxp)->type))
return (0);
goto check_delete;
}
if (*cmpp > 0) {
base = indx + 1;
lim--;
}
}
/*
* Base references the smallest index larger than the supplied DBT's
* data item, potentially both 0 and NUM_ENT.
*/
*indxp = base;
return (0);
check_delete:
/*
* The duplicate may have already been deleted, if it's a btree page,
* in which case we wander around, hoping to find an entry that hasn't
* been deleted. First, wander in a forwardly direction.
*/
save_pgno = (*pp)->pgno;
save_indx = *indxp;
for (++*indxp;;) {
for (; *indxp < NUM_ENT(h); ++*indxp) {
if ((*cmpp = __bam_cmp(dbp,
dbt, h, *indxp, dbp->dup_compare)) != 0)
goto check_delete_rev;
if (!B_DISSET(GET_BKEYDATA(h, *indxp)->type))
return (0);
}
if ((pgno = h->next_pgno) == PGNO_INVALID)
break;
if ((ret = memp_fput(dbp->mpf, h, 0)) != 0)
return (ret);
if ((ret = memp_fget(dbp->mpf, &pgno, 0, pp)) != 0)
goto pg_err;
h = *pp;
*indxp = 0;
}
check_delete_rev:
/* Go back to where we started, and wander in a backwardly direction. */
if (h->pgno != save_pgno) {
if ((ret = memp_fput(dbp->mpf, h, 0)) != 0)
return (ret);
if ((ret = memp_fget(dbp->mpf, &save_pgno, 0, pp)) != 0)
goto pg_err;
h = *pp;
}
for (;;) {
while (*indxp > 0) {
--*indxp;
if ((*cmpp = __bam_cmp(dbp,
dbt, h, *indxp, dbp->dup_compare)) != 0)
goto check_delete_fail;
if (!B_DISSET(GET_BKEYDATA(h, *indxp)->type))
return (0);
}
if ((pgno = h->prev_pgno) == PGNO_INVALID)
break;
if ((ret = memp_fput(dbp->mpf, h, 0)) != 0)
return (ret);
if ((ret = memp_fget(dbp->mpf, &pgno, 0, pp)) != 0)
goto pg_err;
h = *pp;
*indxp = NUM_ENT(h);
}
check_delete_fail:
*cmpp = 1; /* We didn't succeed... */
return (0);
pg_err: __db_pgerr(dbp, pgno);
return (ret);
}