/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996, 1997
* Sleepycat Software. All rights reserved.
*/
#include "config.h"
#ifndef lint
static const char sccsid[] = "@(#)bt_cursor.c 10.37 (Sleepycat) 11/22/97";
#endif /* not lint */
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#endif
#include "db_int.h"
#include "db_page.h"
#include "btree.h"
static int __bam_c_close __P((DBC *));
static int __bam_c_del __P((DBC *, int));
static int __bam_c_first __P((DB *, CURSOR *));
static int __bam_c_get __P((DBC *, DBT *, DBT *, int));
static int __bam_c_last __P((DB *, CURSOR *));
static int __bam_c_next __P((DB *, CURSOR *, int));
static int __bam_c_physdel __P((DB *, CURSOR *, PAGE *));
static int __bam_c_prev __P((DB *, CURSOR *));
static int __bam_c_put __P((DBC *, DBT *, DBT *, int));
static int __bam_c_rget __P((DB *, CURSOR *, DBT *, int));
static int __bam_c_search __P((DB *, CURSOR *, const DBT *, u_int, int, int *));
/* Discard the current page/lock held by a cursor. */
#undef DISCARD
#define DISCARD(dbp, cp) { \
(void)memp_fput(dbp->mpf, (cp)->page, 0); \
(cp)->page = NULL; \
(void)__BT_TLPUT((dbp), (cp)->lock); \
(cp)->lock = LOCK_INVALID; \
}
/*
* __bam_cursor --
* Interface to the cursor functions.
*
* PUBLIC: int __bam_cursor __P((DB *, DB_TXN *, DBC **));
*/
int
__bam_cursor(dbp, txn, dbcp)
DB *dbp;
DB_TXN *txn;
DBC **dbcp;
{
CURSOR *cp;
DBC *dbc;
DEBUG_LWRITE(dbp, txn, "bam_cursor", NULL, NULL, 0);
if ((dbc = (DBC *)__db_calloc(1, sizeof(DBC))) == NULL)
return (ENOMEM);
if ((cp = (CURSOR *)__db_calloc(1, sizeof(CURSOR))) == NULL) {
__db_free(dbc);
return (ENOMEM);
}
cp->dbc = dbc;
cp->pgno = cp->dpgno = PGNO_INVALID;
cp->lock = LOCK_INVALID;
dbc->dbp = dbp;
dbc->txn = txn;
dbc->internal = cp;
dbc->c_close = __bam_c_close;
dbc->c_del = __bam_c_del;
dbc->c_get = __bam_c_get;
dbc->c_put = __bam_c_put;
/*
* All cursors are queued from the master DB structure. Add the
* cursor to that queue.
*/
DB_THREAD_LOCK(dbp);
TAILQ_INSERT_HEAD(&dbp->curs_queue, dbc, links);
DB_THREAD_UNLOCK(dbp);
*dbcp = dbc;
return (0);
}
/*
* __bam_c_close --
* Close a single cursor.
*/
static int
__bam_c_close(dbc)
DBC *dbc;
{
DB *dbp;
int ret;
DEBUG_LWRITE(dbc->dbp, dbc->txn, "bam_c_close", NULL, NULL, 0);
GETHANDLE(dbc->dbp, dbc->txn, &dbp, ret);
ret = __bam_c_iclose(dbp, dbc);
PUTHANDLE(dbp);
return (ret);
}
/*
* __bam_c_iclose --
* Close a single cursor -- internal version.
*
* PUBLIC: int __bam_c_iclose __P((DB *, DBC *));
*/
int
__bam_c_iclose(dbp, dbc)
DB *dbp;
DBC *dbc;
{
CURSOR *cp;
int ret;
cp = dbc->internal;
/* If a cursor key was deleted, perform the actual deletion. */
ret = F_ISSET(cp, C_DELETED) ? __bam_c_physdel(dbp, cp, NULL) : 0;
/* Discard any lock if we're not inside a transaction. */
if (cp->lock != LOCK_INVALID)
(void)__BT_TLPUT(dbp, cp->lock);
/*
* All cursors are queued from the master DB structure. Remove the
* cursor from that queue.
*/
DB_THREAD_LOCK(dbc->dbp);
TAILQ_REMOVE(&dbc->dbp->curs_queue, dbc, links);
DB_THREAD_UNLOCK(dbc->dbp);
/* Discard the structures. */
FREE(dbc->internal, sizeof(CURSOR));
FREE(dbc, sizeof(DBC));
return (ret);
}
/*
* __bam_c_del --
* Delete using a cursor.
*/
static int
__bam_c_del(dbc, flags)
DBC *dbc;
int flags;
{
CURSOR *cp;
DB *dbp;
DB_LOCK lock;
PAGE *h;
db_pgno_t pgno;
db_indx_t indx;
int ret;
DEBUG_LWRITE(dbc->dbp, dbc->txn, "bam_c_del", NULL, NULL, flags);
cp = dbc->internal;
/* Check for invalid flags. */
if ((ret = __db_cdelchk(dbc->dbp, flags,
F_ISSET(dbc->dbp, DB_AM_RDONLY), cp->pgno != PGNO_INVALID)) != 0)
return (ret);
/* If already deleted, return failure. */
if (F_ISSET(cp, C_DELETED | C_REPLACE))
return (DB_KEYEMPTY);
GETHANDLE(dbc->dbp, dbc->txn, &dbp, ret);
/*
* We don't physically delete the record until the cursor moves,
* so we have to have a long-lived write lock on the page instead
* of a long-lived read lock. Note, we have to have a read lock
* to even get here, so we simply discard it.
*/
if (F_ISSET(dbp, DB_AM_LOCKING) && cp->mode != DB_LOCK_WRITE) {
if ((ret = __bam_lget(dbp,
0, cp->pgno, DB_LOCK_WRITE, &lock)) != 0)
goto err;
(void)__BT_TLPUT(dbp, cp->lock);
cp->lock = lock;
cp->mode = DB_LOCK_WRITE;
}
/*
* Acquire the underlying page (which may be different from the above
* page because it may be a duplicate page), and set the on-page and
* in-cursor delete flags. We don't need to lock it as we've already
* write-locked the page leading to it.
*/
if (cp->dpgno == PGNO_INVALID) {
pgno = cp->pgno;
indx = cp->indx;
} else {
pgno = cp->dpgno;
indx = cp->dindx;
}
if ((ret = __bam_pget(dbp, &h, &pgno, 0)) != 0)
goto err;
/* Log the change. */
if (DB_LOGGING(dbp) &&
(ret = __bam_cdel_log(dbp->dbenv->lg_info, dbp->txn, &LSN(h),
0, dbp->log_fileid, PGNO(h), &LSN(h), indx)) != 0) {
(void)memp_fput(dbp->mpf, h, 0);
goto err;
}
/* Set the intent-to-delete flag on the page and in all cursors. */
if (cp->dpgno == PGNO_INVALID)
B_DSET(GET_BKEYDATA(h, indx + O_INDX)->type);
else
B_DSET(GET_BKEYDATA(h, indx)->type);
(void)__bam_ca_delete(dbp, pgno, indx, NULL, 0);
ret = memp_fput(dbp->mpf, h, DB_MPOOL_DIRTY);
err: PUTHANDLE(dbp);
return (ret);
}
/*
* __bam_get --
* Retrieve a key/data pair from the tree.
*
* PUBLIC: int __bam_get __P((DB *, DB_TXN *, DBT *, DBT *, int));
*/
int
__bam_get(argdbp, txn, key, data, flags)
DB *argdbp;
DB_TXN *txn;
DBT *key, *data;
int flags;
{
DBC dbc;
CURSOR cp;
int ret;
DEBUG_LREAD(argdbp, txn, "bam_get", key, NULL, flags);
/* Check for invalid flags. */
if ((ret = __db_getchk(argdbp, key, data, flags)) != 0)
return (ret);
/* Build an internal cursor. */
memset(&cp, 0, sizeof(cp));
cp.dbc = &dbc;
cp.pgno = cp.dpgno = PGNO_INVALID;
cp.lock = LOCK_INVALID;
cp.flags = C_INTERNAL;
/* Build an external cursor. */
memset(&dbc, 0, sizeof(dbc));
dbc.dbp = argdbp;
dbc.txn = txn;
dbc.internal = &cp;
/* Get the key. */
return(__bam_c_get(&dbc,
key, data, LF_ISSET(DB_SET_RECNO) ? DB_SET_RECNO : DB_SET));
}
/*
* __bam_c_get --
* Get using a cursor (btree).
*/
static int
__bam_c_get(dbc, key, data, flags)
DBC *dbc;
DBT *key, *data;
int flags;
{
BTREE *t;
CURSOR *cp, copy;
DB *dbp;
PAGE *h;
int exact, ret;
DEBUG_LREAD(dbc->dbp, dbc->txn, "bam_c_get",
flags == DB_SET || flags == DB_SET_RANGE ? key : NULL, NULL, flags);
cp = dbc->internal;
/* Check for invalid flags. */
if ((ret = __db_cgetchk(dbc->dbp,
key, data, flags, cp->pgno != PGNO_INVALID)) != 0)
return (ret);
GETHANDLE(dbc->dbp, dbc->txn, &dbp, ret);
t = dbp->internal;
/*
* Break out the code to return a cursor's record number. It
* has nothing to do with the cursor get code except that it's
* been rammed into the interface.
*/
if (LF_ISSET(DB_GET_RECNO)) {
ret = __bam_c_rget(dbp, cp, data, flags);
PUTHANDLE(dbp);
return (ret);
}
/* Initialize the cursor for a new retrieval. */
copy = *cp;
cp->page = NULL;
cp->lock = LOCK_INVALID;
switch (flags) {
case DB_CURRENT:
/* It's not possible to return a deleted record. */
if (F_ISSET(cp, C_DELETED | C_REPLACE)) {
PUTHANDLE(dbp);
return (DB_KEYEMPTY);
}
/* Get the page with the current item on it. */
if ((ret = __bam_pget(dbp, &cp->page, &cp->pgno, 0)) != 0)
goto err;
break;
case DB_NEXT:
if (cp->pgno != PGNO_INVALID) {
if ((ret = __bam_c_next(dbp, cp, 1)) != 0)
goto err;
break;
}
/* FALLTHROUGH */
case DB_FIRST:
if ((ret = __bam_c_first(dbp, cp)) != 0)
goto err;
break;
case DB_PREV:
if (cp->pgno != PGNO_INVALID) {
if ((ret = __bam_c_prev(dbp, cp)) != 0)
goto err;
break;
}
/* FALLTHROUGH */
case DB_LAST:
if ((ret = __bam_c_last(dbp, cp)) != 0)
goto err;
break;
case DB_SET_RECNO:
exact = 1;
if ((ret =
__bam_c_search(dbp, cp, key, S_FIND, 1, &exact)) != 0)
goto err;
break;
case DB_SET:
exact = 1;
if ((ret =
__bam_c_search(dbp, cp, key, S_FIND, 0, &exact)) != 0)
goto err;
break;
case DB_SET_RANGE:
exact = 0;
if ((ret =
__bam_c_search(dbp, cp, key, S_FIND, 0, &exact)) != 0)
goto err;
break;
}
/*
* Return the key if the user didn't give us one. If we've moved to
* a duplicate page, we may no longer have a pointer to the main page,
* so we have to go get it. We know that it's already read-locked,
* however, so we don't have to acquire a new lock.
*/
if (flags != DB_SET) {
if (cp->dpgno != PGNO_INVALID) {
if ((ret = __bam_pget(dbp, &h, &cp->pgno, 0)) != 0)
goto err;
} else
h = cp->page;
ret = __db_ret(dbp,
h, cp->indx, key, &t->bt_rkey.data, &t->bt_rkey.ulen);
if (cp->dpgno != PGNO_INVALID)
(void)memp_fput(dbp->mpf, h, 0);
if (ret)
goto err;
}
/* Return the data. */
if ((ret = __db_ret(dbp, cp->page,
cp->dpgno == PGNO_INVALID ? cp->indx + O_INDX : cp->dindx,
data, &t->bt_rdata.data, &t->bt_rdata.ulen)) != 0)
goto err;
/*
* If the previous cursor record has been deleted, delete it. The
* returned key isn't a deleted key, so clear the flag.
*/
if (F_ISSET(©, C_DELETED) && __bam_c_physdel(dbp, ©, cp->page))
goto err;
F_CLR(cp, C_DELETED | C_REPLACE);
/* Release the previous lock, if any. */
if (copy.lock != LOCK_INVALID)
(void)__BT_TLPUT(dbp, copy.lock);
/* Release the pinned page. */
ret = memp_fput(dbp->mpf, cp->page, 0);
/* Internal cursors don't hold locks. */
if (F_ISSET(cp, C_INTERNAL) && cp->lock != LOCK_INVALID)
(void)__BT_TLPUT(dbp, cp->lock);
++t->lstat.bt_get;
if (0) {
err: if (cp->page != NULL)
(void)memp_fput(dbp->mpf, cp->page, 0);
if (cp->lock != LOCK_INVALID)
(void)__BT_TLPUT(dbp, cp->lock);
*cp = copy;
}
PUTHANDLE(dbp);
return (ret);
}
/*
* __bam_c_rget --
* Return the record number for a cursor.
*/
static int
__bam_c_rget(dbp, cp, data, flags)
DB *dbp;
CURSOR *cp;
DBT *data;
int flags;
{
BTREE *t;
DBT dbt;
db_recno_t recno;
int exact, ret;
/* Get the page with the current item on it. */
if ((ret = __bam_pget(dbp, &cp->page, &cp->pgno, 0)) != 0)
return (ret);
/* Get a copy of the key. */
memset(&dbt, 0, sizeof(DBT));
dbt.flags = DB_DBT_MALLOC | DB_DBT_INTERNAL;
if ((ret = __db_ret(dbp, cp->page, cp->indx, &dbt, NULL, NULL)) != 0)
goto err;
exact = 1;
if ((ret = __bam_search(dbp, &dbt, S_FIND, 1, &recno, &exact)) != 0)
goto err;
t = dbp->internal;
ret = __db_retcopy(data, &recno, sizeof(recno),
&t->bt_rdata.data, &t->bt_rdata.ulen, dbp->db_malloc);
/* Release the stack. */
__bam_stkrel(dbp);
err: (void)memp_fput(dbp->mpf, cp->page, 0);
__db_free(dbt.data);
return (ret);
}
/*
* __bam_c_put --
* Put using a cursor.
*/
static int
__bam_c_put(dbc, key, data, flags)
DBC *dbc;
DBT *key, *data;
int flags;
{
BTREE *t;
CURSOR *cp, copy;
DB *dbp;
DBT dbt;
db_indx_t indx;
db_pgno_t pgno;
int exact, needkey, ret;
void *arg;
DEBUG_LWRITE(dbc->dbp, dbc->txn, "bam_c_put",
flags == DB_KEYFIRST || flags == DB_KEYLAST ? key : NULL,
data, flags);
cp = dbc->internal;
if ((ret = __db_cputchk(dbc->dbp, key, data, flags,
F_ISSET(dbc->dbp, DB_AM_RDONLY), cp->pgno != PGNO_INVALID)) != 0)
return (ret);
GETHANDLE(dbc->dbp, dbc->txn, &dbp, ret);
t = dbp->internal;
/* Initialize the cursor for a new retrieval. */
copy = *cp;
cp->page = NULL;
cp->lock = LOCK_INVALID;
/*
* To split, we need a valid key for the page. Since it's a cursor,
* we have to build one.
*/
if (0) {
split: if (needkey) {
memset(&dbt, 0, sizeof(DBT));
ret = __db_ret(dbp, cp->page, indx,
&dbt, &t->bt_rkey.data, &t->bt_rkey.ulen);
DISCARD(dbp, cp);
if (ret)
goto err;
arg = &dbt;
} else {
(void)__bam_stkrel(dbp);
arg = key;
}
if ((ret = __bam_split(dbp, arg)) != 0)
goto err;
}
/* If there's no key supplied, use the cursor. */
if (flags == DB_KEYFIRST || flags == DB_KEYLAST)
needkey = 0;
else {
needkey = 1;
if (cp->dpgno == PGNO_INVALID) {
pgno = cp->pgno;
indx = cp->indx;
} else {
pgno = cp->dpgno;
indx = cp->dindx;
}
/* Acquire the current page. */
if ((ret = __bam_lget(dbp,
0, cp->pgno, DB_LOCK_WRITE, &cp->lock)) != 0)
goto err;
if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
goto err;
}
ret = 0;
switch (flags) {
case DB_AFTER:
case DB_BEFORE:
case DB_CURRENT:
if ((ret = __bam_iitem(dbp, &cp->page,
&indx, key, data, flags, 0)) == DB_NEEDSPLIT)
goto split;
break;
case DB_KEYFIRST:
exact = 0;
if ((ret =
__bam_c_search(dbp, cp, key, S_KEYFIRST, 0, &exact)) != 0)
goto err;
indx = cp->dpgno == PGNO_INVALID ? cp->indx : cp->dindx;
if ((ret = __bam_iitem(dbp, &cp->page, &indx, key,
data, DB_BEFORE, exact ? 0 : BI_NEWKEY)) == DB_NEEDSPLIT)
goto split;
if (ret)
goto err;
break;
case DB_KEYLAST:
exact = 0;
if ((ret =
__bam_c_search(dbp, cp, key, S_KEYLAST, 0, &exact)) != 0)
goto err;
indx = cp->dpgno == PGNO_INVALID ? cp->indx : cp->dindx;
if ((ret = __bam_iitem(dbp, &cp->page, &indx, key,
data, DB_AFTER, exact ? 0 : BI_NEWKEY)) == DB_NEEDSPLIT)
goto split;
break;
}
if (ret)
goto err;
/*
* Update the cursor to point to the new entry. The new entry was
* stored on the current page, because we split pages until it was
* possible.
*/
if (cp->dpgno == PGNO_INVALID)
cp->indx = indx;
else
cp->dindx = indx;
/*
* If the previous cursor record has been deleted, delete it. The
* returned key isn't a deleted key, so clear the flag.
*/
if (F_ISSET(©, C_DELETED) &&
(ret = __bam_c_physdel(dbp, ©, cp->page)) != 0)
goto err;
F_CLR(cp, C_DELETED | C_REPLACE);
/* Release the previous lock, if any. */
if (copy.lock != LOCK_INVALID)
(void)__BT_TLPUT(dbp, copy.lock);
/* Discard the pinned page. */
ret = memp_fput(dbp->mpf, cp->page, 0);
if (0) {
err: if (cp->page != NULL)
(void)memp_fput(dbp->mpf, cp->page, 0);
if (cp->lock != LOCK_INVALID)
(void)__BT_TLPUT(dbp, cp->lock);
*cp = copy;
}
PUTHANDLE(dbp);
return (ret);
}
/*
* __bam_c_first --
* Return the first record.
*/
static int
__bam_c_first(dbp, cp)
DB *dbp;
CURSOR *cp;
{
db_pgno_t pgno;
int ret;
/* Walk down the left-hand side of the tree. */
for (pgno = PGNO_ROOT;;) {
if ((ret =
__bam_lget(dbp, 0, pgno, DB_LOCK_READ, &cp->lock)) != 0)
return (ret);
if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
return (ret);
/* If we find a leaf page, we're done. */
if (ISLEAF(cp->page))
break;
pgno = GET_BINTERNAL(cp->page, 0)->pgno;
DISCARD(dbp, cp);
}
cp->pgno = cp->page->pgno;
cp->indx = 0;
cp->dpgno = PGNO_INVALID;
/* If it's an empty page or a deleted record, go to the next one. */
if (NUM_ENT(cp->page) == 0 ||
B_DISSET(GET_BKEYDATA(cp->page, cp->indx + O_INDX)->type))
if ((ret = __bam_c_next(dbp, cp, 0)) != 0)
return (ret);
/* If it's a duplicate reference, go to the first entry. */
if ((ret = __bam_ovfl_chk(dbp, cp, O_INDX, 0)) != 0)
return (ret);
/* If it's a deleted record, go to the next one. */
if (cp->dpgno != PGNO_INVALID &&
B_DISSET(GET_BKEYDATA(cp->page, cp->dindx)->type))
if ((ret = __bam_c_next(dbp, cp, 0)) != 0)
return (ret);
return (0);
}
/*
* __bam_c_last --
* Return the last record.
*/
static int
__bam_c_last(dbp, cp)
DB *dbp;
CURSOR *cp;
{
db_pgno_t pgno;
int ret;
/* Walk down the right-hand side of the tree. */
for (pgno = PGNO_ROOT;;) {
if ((ret =
__bam_lget(dbp, 0, pgno, DB_LOCK_READ, &cp->lock)) != 0)
return (ret);
if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
return (ret);
/* If we find a leaf page, we're done. */
if (ISLEAF(cp->page))
break;
pgno =
GET_BINTERNAL(cp->page, NUM_ENT(cp->page) - O_INDX)->pgno;
DISCARD(dbp, cp);
}
cp->pgno = cp->page->pgno;
cp->indx = NUM_ENT(cp->page) == 0 ? 0 : NUM_ENT(cp->page) - P_INDX;
cp->dpgno = PGNO_INVALID;
/* If it's an empty page or a deleted record, go to the previous one. */
if (NUM_ENT(cp->page) == 0 ||
B_DISSET(GET_BKEYDATA(cp->page, cp->indx + O_INDX)->type))
if ((ret = __bam_c_prev(dbp, cp)) != 0)
return (ret);
/* If it's a duplicate reference, go to the last entry. */
if ((ret = __bam_ovfl_chk(dbp, cp, cp->indx + O_INDX, 1)) != 0)
return (ret);
/* If it's a deleted record, go to the previous one. */
if (cp->dpgno != PGNO_INVALID &&
B_DISSET(GET_BKEYDATA(cp->page, cp->dindx)->type))
if ((ret = __bam_c_prev(dbp, cp)) != 0)
return (ret);
return (0);
}
/*
* __bam_c_next --
* Move to the next record.
*/
static int
__bam_c_next(dbp, cp, initial_move)
DB *dbp;
CURSOR *cp;
int initial_move;
{
db_indx_t adjust, indx;
db_pgno_t pgno;
int ret;
/*
* We're either moving through a page of duplicates or a btree leaf
* page.
*/
if (cp->dpgno == PGNO_INVALID) {
adjust = dbp->type == DB_BTREE ? P_INDX : O_INDX;
pgno = cp->pgno;
indx = cp->indx;
} else {
adjust = O_INDX;
pgno = cp->dpgno;
indx = cp->dindx;
}
if (cp->page == NULL) {
if ((ret =
__bam_lget(dbp, 0, pgno, DB_LOCK_READ, &cp->lock)) != 0)
return (ret);
if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
return (ret);
}
/*
* If at the end of the page, move to a subsequent page.
*
* !!!
* Check for >= NUM_ENT. If we're here as the result of a search that
* landed us on NUM_ENT, we'll increment indx before we test.
*
* !!!
* This code handles empty pages and pages with only deleted entries.
*/
if (initial_move)
indx += adjust;
for (;;) {
if (indx >= NUM_ENT(cp->page)) {
pgno = cp->page->next_pgno;
DISCARD(dbp, cp);
/*
* If we're in a btree leaf page, we've reached the end
* of the tree. If we've reached the end of a page of
* duplicates, continue from the btree leaf page where
* we found this page of duplicates.
*/
if (pgno == PGNO_INVALID) {
/* If in a btree leaf page, it's EOF. */
if (cp->dpgno == PGNO_INVALID)
return (DB_NOTFOUND);
/* Continue from the last btree leaf page. */
cp->dpgno = PGNO_INVALID;
adjust = P_INDX;
pgno = cp->pgno;
indx = cp->indx + P_INDX;
} else
indx = 0;
if ((ret = __bam_lget(dbp,
0, pgno, DB_LOCK_READ, &cp->lock)) != 0)
return (ret);
if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
return (ret);
continue;
}
/* Ignore deleted records. */
if (dbp->type == DB_BTREE &&
((cp->dpgno == PGNO_INVALID &&
B_DISSET(GET_BKEYDATA(cp->page, indx + O_INDX)->type)) ||
(cp->dpgno != PGNO_INVALID &&
B_DISSET(GET_BKEYDATA(cp->page, indx)->type)))) {
indx += adjust;
continue;
}
/*
* If we're not in a duplicates page, check to see if we've
* found a page of duplicates, in which case we move to the
* first entry.
*/
if (cp->dpgno == PGNO_INVALID) {
cp->pgno = cp->page->pgno;
cp->indx = indx;
if ((ret =
__bam_ovfl_chk(dbp, cp, indx + O_INDX, 0)) != 0)
return (ret);
if (cp->dpgno != PGNO_INVALID) {
indx = cp->dindx;
adjust = O_INDX;
continue;
}
} else {
cp->dpgno = cp->page->pgno;
cp->dindx = indx;
}
break;
}
return (0);
}
/*
* __bam_c_prev --
* Move to the previous record.
*/
static int
__bam_c_prev(dbp, cp)
DB *dbp;
CURSOR *cp;
{
db_indx_t indx, adjust;
db_pgno_t pgno;
int ret, set_indx;
/*
* We're either moving through a page of duplicates or a btree leaf
* page.
*/
if (cp->dpgno == PGNO_INVALID) {
adjust = dbp->type == DB_BTREE ? P_INDX : O_INDX;
pgno = cp->pgno;
indx = cp->indx;
} else {
adjust = O_INDX;
pgno = cp->dpgno;
indx = cp->dindx;
}
if (cp->page == NULL) {
if ((ret =
__bam_lget(dbp, 0, pgno, DB_LOCK_READ, &cp->lock)) != 0)
return (ret);
if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
return (ret);
}
/*
* If at the beginning of the page, move to any previous one.
*
* !!!
* This code handles empty pages and pages with only deleted entries.
*/
for (;;) {
if (indx == 0) {
pgno = cp->page->prev_pgno;
DISCARD(dbp, cp);
/*
* If we're in a btree leaf page, we've reached the
* beginning of the tree. If we've reached the first
* of a page of duplicates, continue from the btree
* leaf page where we found this page of duplicates.
*/
if (pgno == PGNO_INVALID) {
/* If in a btree leaf page, it's SOF. */
if (cp->dpgno == PGNO_INVALID)
return (DB_NOTFOUND);
/* Continue from the last btree leaf page. */
cp->dpgno = PGNO_INVALID;
adjust = P_INDX;
pgno = cp->pgno;
indx = cp->indx;
set_indx = 0;
} else
set_indx = 1;
if ((ret = __bam_lget(dbp,
0, pgno, DB_LOCK_READ, &cp->lock)) != 0)
return (ret);
if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
return (ret);
if (set_indx)
indx = NUM_ENT(cp->page);
if (indx == 0)
continue;
}
/* Ignore deleted records. */
indx -= adjust;
if (dbp->type == DB_BTREE &&
((cp->dpgno == PGNO_INVALID &&
B_DISSET(GET_BKEYDATA(cp->page, indx + O_INDX)->type)) ||
(cp->dpgno != PGNO_INVALID &&
B_DISSET(GET_BKEYDATA(cp->page, indx)->type))))
continue;
/*
* If we're not in a duplicates page, check to see if we've
* found a page of duplicates, in which case we move to the
* last entry.
*/
if (cp->dpgno == PGNO_INVALID) {
cp->pgno = cp->page->pgno;
cp->indx = indx;
if ((ret =
__bam_ovfl_chk(dbp, cp, indx + O_INDX, 1)) != 0)
return (ret);
if (cp->dpgno != PGNO_INVALID) {
indx = cp->dindx + O_INDX;
adjust = O_INDX;
continue;
}
} else {
cp->dpgno = cp->page->pgno;
cp->dindx = indx;
}
break;
}
return (0);
}
/*
* __bam_c_search --
* Move to a specified record.
*/
static int
__bam_c_search(dbp, cp, key, flags, isrecno, exactp)
DB *dbp;
CURSOR *cp;
const DBT *key;
u_int flags;
int isrecno, *exactp;
{
BTREE *t;
db_recno_t recno;
int needexact, ret;
t = dbp->internal;
needexact = *exactp;
/*
* Find any matching record; the search function pins the page. Make
* sure it's a valid key (__bam_search may return an index just past
* the end of a page) and return it.
*/
if (isrecno) {
if ((ret = __ram_getno(dbp, key, &recno, 0)) != 0)
return (ret);
ret = __bam_rsearch(dbp, &recno, flags, 1, exactp);
} else
ret = __bam_search(dbp, key, flags, 1, NULL, exactp);
if (ret != 0)
return (ret);
cp->page = t->bt_csp->page;
cp->pgno = cp->page->pgno;
cp->indx = t->bt_csp->indx;
cp->lock = t->bt_csp->lock;
cp->dpgno = PGNO_INVALID;
/*
* If we have an exact match, make sure that we're not looking at a
* chain of duplicates -- if so, move to an entry in that chain.
*/
if (*exactp) {
if ((ret = __bam_ovfl_chk(dbp,
cp, cp->indx + O_INDX, LF_ISSET(S_DUPLAST))) != 0)
return (ret);
} else
if (needexact)
return (DB_NOTFOUND);
/* If past the end of a page, find the next entry. */
if (cp->indx == NUM_ENT(cp->page) &&
(ret = __bam_c_next(dbp, cp, 0)) != 0)
return (ret);
/* If it's a deleted record, go to the next or previous one. */
if (cp->dpgno != PGNO_INVALID &&
B_DISSET(GET_BKEYDATA(cp->page, cp->dindx)->type))
if (flags == S_KEYLAST) {
if ((ret = __bam_c_prev(dbp, cp)) != 0)
return (ret);
} else
if ((ret = __bam_c_next(dbp, cp, 0)) != 0)
return (ret);
return (0);
}
/*
* __bam_ovfl_chk --
* Check for an overflow record, and if found, move to the correct
* record.
*
* PUBLIC: int __bam_ovfl_chk __P((DB *, CURSOR *, u_int32_t, int));
*/
int
__bam_ovfl_chk(dbp, cp, indx, to_end)
DB *dbp;
CURSOR *cp;
u_int32_t indx;
int to_end;
{
BOVERFLOW *bo;
db_pgno_t pgno;
int ret;
/* Check for an overflow entry. */
bo = GET_BOVERFLOW(cp->page, indx);
if (B_TYPE(bo->type) != B_DUPLICATE)
return (0);
/*
* If we find one, go to the duplicates page, and optionally move
* to the last record on that page.
*
* XXX
* We don't lock duplicates pages, we've already got the correct
* lock on the main page.
*/
pgno = bo->pgno;
if ((ret = memp_fput(dbp->mpf, cp->page, 0)) != 0)
return (ret);
cp->page = NULL;
if (to_end) {
if ((ret = __db_dend(dbp, pgno, &cp->page)) != 0)
return (ret);
indx = NUM_ENT(cp->page) - O_INDX;
} else {
if ((ret = __bam_pget(dbp, &cp->page, &pgno, 0)) != 0)
return (ret);
indx = 0;
}
/* Update the duplicate entry in the cursor. */
cp->dpgno = cp->page->pgno;
cp->dindx = indx;
return (0);
}
#ifdef DEBUG
/*
* __bam_cprint --
* Display the current btree cursor list.
*/
int
__bam_cprint(dbp)
DB *dbp;
{
CURSOR *cp;
DBC *dbc;
DB_THREAD_LOCK(dbp);
for (dbc = TAILQ_FIRST(&dbp->curs_queue);
dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
cp = (CURSOR *)dbc->internal;
fprintf(stderr,
"%#0x: page: %lu index: %lu dpage %lu dindex: %lu",
(u_int)cp, (u_long)cp->pgno, (u_long)cp->indx,
(u_long)cp->dpgno, (u_long)cp->dindx);
if (F_ISSET(cp, C_DELETED))
fprintf(stderr, "(deleted)");
fprintf(stderr, "\n");
}
DB_THREAD_UNLOCK(dbp);
return (0);
}
#endif /* DEBUG */
/*
* __bam_ca_delete --
* Check if any of the cursors refer to the item we are about to delete,
* returning the number of cursors that refer to the item in question.
*
* PUBLIC: int __bam_ca_delete __P((DB *, db_pgno_t, u_int32_t, CURSOR *, int));
*/
int
__bam_ca_delete(dbp, pgno, indx, curs, key_delete)
DB *dbp;
db_pgno_t pgno;
u_int32_t indx;
CURSOR *curs;
int key_delete;
{
DBC *dbc;
CURSOR *cp;
int count;
/*
* Adjust the cursors. We don't have to review the cursors for any
* process other than the current one, because we have the page write
* locked at this point, and any other process had better be using a
* different locker ID, meaning that only cursors in our process can
* be on the page.
*
* It's possible for multiple cursors within the thread to have write
* locks on the same page, but, cursors within a thread must be single
* threaded, so all we're locking here is the cursor linked list.
*/
DB_THREAD_LOCK(dbp);
for (count = 0, dbc = TAILQ_FIRST(&dbp->curs_queue);
dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
cp = (CURSOR *)dbc->internal;
/*
* Optionally, a cursor passed in is the one initiating the
* delete, so we don't want to count it or set its deleted
* flag. Otherwise, if a cursor refers to the item, then we
* set its deleted flag.
*/
if (curs == cp)
continue;
/*
* If we're deleting the key itself and not just one of its
* duplicates, repoint the cursor to the main-page key/data
* pair, everything else is about to be discarded.
*/
if (key_delete || cp->dpgno == PGNO_INVALID) {
if (cp->pgno == pgno && cp->indx == indx) {
cp->dpgno = PGNO_INVALID;
++count;
F_SET(cp, C_DELETED);
}
} else
if (cp->dpgno == pgno && cp->dindx == indx) {
++count;
F_SET(cp, C_DELETED);
}
}
DB_THREAD_UNLOCK(dbp);
return (count);
}
/*
* __bam_ca_di --
* Adjust the cursors during a delete or insert.
*
* PUBLIC: void __bam_ca_di __P((DB *, db_pgno_t, u_int32_t, int));
*/
void
__bam_ca_di(dbp, pgno, indx, value)
DB *dbp;
db_pgno_t pgno;
u_int32_t indx;
int value;
{
CURSOR *cp;
DBC *dbc;
/* Recno is responsible for its own adjustments. */
if (dbp->type == DB_RECNO)
return;
/*
* Adjust the cursors. See the comment in __bam_ca_delete().
*/
DB_THREAD_LOCK(dbp);
for (dbc = TAILQ_FIRST(&dbp->curs_queue);
dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
cp = (CURSOR *)dbc->internal;
if (cp->pgno == pgno && cp->indx >= indx)
cp->indx += value;
if (cp->dpgno == pgno && cp->dindx >= indx)
cp->dindx += value;
}
DB_THREAD_UNLOCK(dbp);
}
/*
* __bam_ca_dup --
* Adjust the cursors when moving data items to a duplicates page.
*
* PUBLIC: void __bam_ca_dup __P((DB *,
* PUBLIC: db_pgno_t, u_int32_t, u_int32_t, db_pgno_t, u_int32_t));
*/
void
__bam_ca_dup(dbp, fpgno, first, fi, tpgno, ti)
DB *dbp;
db_pgno_t fpgno, tpgno;
u_int32_t first, fi, ti;
{
CURSOR *cp;
DBC *dbc;
/*
* Adjust the cursors. See the comment in __bam_ca_delete().
*
* No need to test duplicates, this only gets called when moving
* leaf page data items onto a duplicates page.
*/
DB_THREAD_LOCK(dbp);
for (dbc = TAILQ_FIRST(&dbp->curs_queue);
dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
cp = (CURSOR *)dbc->internal;
/*
* Ignore matching entries that have already been moved,
* we move from the same location on the leaf page more
* than once.
*/
if (cp->dpgno == PGNO_INVALID &&
cp->pgno == fpgno && cp->indx == fi) {
cp->indx = first;
cp->dpgno = tpgno;
cp->dindx = ti;
}
}
DB_THREAD_UNLOCK(dbp);
}
/*
* __bam_ca_move --
* Adjust the cursors when moving data items to another page.
*
* PUBLIC: void __bam_ca_move __P((DB *, BTREE *, db_pgno_t, db_pgno_t));
*/
void
__bam_ca_move(dbp, t, fpgno, tpgno)
DB *dbp;
BTREE *t;
db_pgno_t fpgno, tpgno;
{
CURSOR *cp;
DBC *dbc;
/* Recno is responsible for its own adjustments. */
if (dbp->type == DB_RECNO)
return;
/*
* Adjust the cursors. See the comment in __bam_ca_delete().
*
* No need to test duplicates, this only gets called when copying
* over the root page with a leaf or internal page.
*/
DB_THREAD_LOCK(dbp);
for (dbc = TAILQ_FIRST(&dbp->curs_queue);
dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
cp = (CURSOR *)dbc->internal;
if (cp->pgno == fpgno)
cp->pgno = tpgno;
}
DB_THREAD_UNLOCK(dbp);
}
/*
* __bam_ca_replace --
* Check if any of the cursors refer to the item we are about to replace.
* If so, their flags should be changed from deleted to replaced.
*
* PUBLIC: void __bam_ca_replace
* PUBLIC: __P((DB *, db_pgno_t, u_int32_t, ca_replace_arg));
*/
void
__bam_ca_replace(dbp, pgno, indx, pass)
DB *dbp;
db_pgno_t pgno;
u_int32_t indx;
ca_replace_arg pass;
{
CURSOR *cp;
DBC *dbc;
/*
* Adjust the cursors. See the comment in __bam_ca_delete().
*
* Find any cursors that have logically deleted a record we're about
* to overwrite.
*
* Pass == REPLACE_SETUP:
* Set C_REPLACE_SETUP so we can find the cursors again.
*
* Pass == REPLACE_SUCCESS:
* Clear C_DELETED and C_REPLACE_SETUP, set C_REPLACE, the
* overwrite was successful.
*
* Pass == REPLACE_FAILED:
* Clear C_REPLACE_SETUP, the overwrite failed.
*
* For REPLACE_SUCCESS and REPLACE_FAILED, we reset the indx value
* for the cursor as it may have been changed by other cursor update
* routines as the item was deleted/inserted.
*/
DB_THREAD_LOCK(dbp);
switch (pass) {
case REPLACE_SETUP: /* Setup. */
for (dbc = TAILQ_FIRST(&dbp->curs_queue);
dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
cp = (CURSOR *)dbc->internal;
if ((cp->pgno == pgno && cp->indx == indx) ||
(cp->dpgno == pgno && cp->dindx == indx))
F_SET(cp, C_REPLACE_SETUP);
}
break;
case REPLACE_SUCCESS: /* Overwrite succeeded. */
for (dbc = TAILQ_FIRST(&dbp->curs_queue);
dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
cp = (CURSOR *)dbc->internal;
if (F_ISSET(cp, C_REPLACE_SETUP)) {
if (cp->dpgno == pgno)
cp->dindx = indx;
if (cp->pgno == pgno)
cp->indx = indx;
F_SET(cp, C_REPLACE);
F_CLR(cp, C_DELETED | C_REPLACE_SETUP);
}
}
break;
case REPLACE_FAILED: /* Overwrite failed. */
for (dbc = TAILQ_FIRST(&dbp->curs_queue);
dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
cp = (CURSOR *)dbc->internal;
if (F_ISSET(cp, C_REPLACE_SETUP)) {
if (cp->dpgno == pgno)
cp->dindx = indx;
if (cp->pgno == pgno)
cp->indx = indx;
F_CLR(cp, C_REPLACE_SETUP);
}
}
break;
}
DB_THREAD_UNLOCK(dbp);
}
/*
* __bam_ca_split --
* Adjust the cursors when splitting a page.
*
* PUBLIC: void __bam_ca_split __P((DB *,
* PUBLIC: db_pgno_t, db_pgno_t, db_pgno_t, u_int32_t, int));
*/
void
__bam_ca_split(dbp, ppgno, lpgno, rpgno, split_indx, cleft)
DB *dbp;
db_pgno_t ppgno, lpgno, rpgno;
u_int32_t split_indx;
int cleft;
{
DBC *dbc;
CURSOR *cp;
/* Recno is responsible for its own adjustments. */
if (dbp->type == DB_RECNO)
return;
/*
* Adjust the cursors. See the comment in __bam_ca_delete().
*
* If splitting the page that a cursor was on, the cursor has to be
* adjusted to point to the same record as before the split. Most
* of the time we don't adjust pointers to the left page, because
* we're going to copy its contents back over the original page. If
* the cursor is on the right page, it is decremented by the number of
* records split to the left page.
*/
DB_THREAD_LOCK(dbp);
for (dbc = TAILQ_FIRST(&dbp->curs_queue);
dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
cp = (CURSOR *)dbc->internal;
if (cp->pgno == ppgno)
if (cp->indx < split_indx) {
if (cleft)
cp->pgno = lpgno;
} else {
cp->pgno = rpgno;
cp->indx -= split_indx;
}
if (cp->dpgno == ppgno)
if (cp->dindx < split_indx) {
if (cleft)
cp->dpgno = lpgno;
} else {
cp->dpgno = rpgno;
cp->dindx -= split_indx;
}
}
DB_THREAD_UNLOCK(dbp);
}
/*
* __bam_c_physdel --
* Actually do the cursor deletion.
*/
static int
__bam_c_physdel(dbp, cp, h)
DB *dbp;
CURSOR *cp;
PAGE *h;
{
BOVERFLOW bo;
BTREE *t;
DBT dbt;
DB_LOCK lock;
db_indx_t indx;
db_pgno_t pgno, next_pgno, prev_pgno;
int local, normal, ret;
t = dbp->internal;
ret = 0;
/* Figure out what we're deleting. */
if (cp->dpgno == PGNO_INVALID) {
pgno = cp->pgno;
indx = cp->indx;
} else {
pgno = cp->dpgno;
indx = cp->dindx;
}
/*
* If the item is referenced by another cursor, leave it up to that
* cursor to do the delete.
*/
if (__bam_ca_delete(dbp, pgno, indx, cp, 0) != 0)
return (0);
/*
* If we don't already have the page locked, get it and delete the
* items.
*/
if ((h == NULL || h->pgno != pgno)) {
if ((ret = __bam_lget(dbp, 0, pgno, DB_LOCK_WRITE, &lock)) != 0)
return (ret);
if ((ret = __bam_pget(dbp, &h, &pgno, 0)) != 0)
return (ret);
local = 1;
} else
local = 0;
/*
* If we're deleting a duplicate entry and there are other duplicate
* entries remaining, call the common code to do the work and fix up
* the parent page as necessary. Otherwise, do a normal btree delete.
*
* There are 5 possible cases:
*
* 1. It's not a duplicate item: do a normal btree delete.
* 2. It's a duplicate item:
* 2a: We delete an item from a page of duplicates, but there are
* more items on the page.
* 2b: We delete the last item from a page of duplicates, deleting
* the last duplicate.
* 2c: We delete the last item from a page of duplicates, but there
* is a previous page of duplicates.
* 2d: We delete the last item from a page of duplicates, but there
* is a following page of duplicates.
*
* In the case of:
*
* 1: There's nothing further to do.
* 2a: There's nothing further to do.
* 2b: Do the normal btree delete instead of a duplicate delete, as
* that deletes both the duplicate chain and the parent page's
* entry.
* 2c: There's nothing further to do.
* 2d: Delete the duplicate, and update the parent page's entry.
*/
if (TYPE(h) == P_DUPLICATE) {
pgno = PGNO(h);
prev_pgno = PREV_PGNO(h);
next_pgno = NEXT_PGNO(h);
if (NUM_ENT(h) == 1 &&
prev_pgno == PGNO_INVALID && next_pgno == PGNO_INVALID)
normal = 1;
else {
normal = 0;
/* Delete the duplicate. */
if ((ret = __db_drem(dbp, &h, indx, __bam_free)) != 0)
goto err;
/*
* 2a: h != NULL, h->pgno == pgno
* 2b: We don't reach this clause, as the above test
* was true.
* 2c: h == NULL, prev_pgno != PGNO_INVALID
* 2d: h != NULL, next_pgno != PGNO_INVALID
*
* Test for 2a and 2c: if we didn't empty the current
* page or there was a previous page of duplicates, we
* don't need to touch the parent page.
*/
if ((h != NULL && pgno == h->pgno) ||
prev_pgno != PGNO_INVALID)
goto done;
}
/* Release any page we're holding and its lock. */
if (local) {
if (h != NULL)
(void)memp_fput(dbp->mpf, h, 0);
(void)__BT_TLPUT(dbp, lock);
local = 0;
}
/* Acquire the parent page. */
if ((ret =
__bam_lget(dbp, 0, cp->pgno, DB_LOCK_WRITE, &lock)) != 0)
goto err;
if ((ret = __bam_pget(dbp, &h, &cp->pgno, 0)) != 0) {
(void)__BT_TLPUT(dbp, lock);
goto err;
}
local = 1;
/* Switch to the parent page's entry. */
indx = cp->indx;
if (normal)
goto btd;
/*
* Copy, delete, update, add-back the parent page's data entry.
*
* XXX
* This may be a performance/logging problem. We should add a
* log message which simply logs/updates a random set of bytes
* on a page, and use it instead of doing a delete/add pair.
*/
indx += O_INDX;
bo = *GET_BOVERFLOW(h, indx);
(void)__db_ditem(dbp, h, indx, BOVERFLOW_SIZE);
bo.pgno = next_pgno;
memset(&dbt, 0, sizeof(dbt));
dbt.data = &bo;
dbt.size = BOVERFLOW_SIZE;
(void)__db_pitem(dbp, h, indx, BOVERFLOW_SIZE, &dbt, NULL);
(void)memp_fset(dbp->mpf, h, DB_MPOOL_DIRTY);
goto done;
}
/* Otherwise, do a normal btree delete. */
btd: if ((ret = __bam_ditem(dbp, h, indx)) != 0)
goto err;
if ((ret = __bam_ditem(dbp, h, indx)) != 0)
goto err;
/*
* If the page is empty, delete it. To delete a leaf page we need a
* copy of a key from the page. We use the first one that was there,
* since it's the last key that the page held. We malloc the page
* information instead of using the return key/data memory because
* we've already set them -- the reason that we've already set them
* is because we're (potentially) about to do a reverse split, which
* would make our saved page information useless.
*
* XXX
* The following operations to delete a page might deadlock. I think
* that's OK. The problem is if we're deleting an item because we're
* closing cursors because we've already deadlocked and want to call
* txn_abort(). If we fail due to deadlock, we'll leave an locked
* empty page in the tree, which won't be empty long because we're
* going to undo the delete.
*/
if (NUM_ENT(h) == 0 && h->pgno != PGNO_ROOT) {
memset(&dbt, 0, sizeof(DBT));
dbt.flags = DB_DBT_MALLOC | DB_DBT_INTERNAL;
if ((ret = __db_ret(dbp, h, 0, &dbt, NULL, NULL)) != 0)
goto err;
if (local) {
(void)memp_fput(dbp->mpf, h, 0);
(void)__BT_TLPUT(dbp, lock);
local = 0;
}
ret = __bam_dpage(dbp, &dbt);
__db_free(dbt.data);
}
err:
done: if (local) {
(void)memp_fput(dbp->mpf, h, 0);
(void)__BT_TLPUT(dbp, lock);
}
if (ret == 0)
++t->lstat.bt_deleted;
return (ret);
}