[apple/libc.git] / db / btree / bt_put.c

/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1990, 1993
 *	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 <sys/types.h>

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <db.h>
#include "btree.h"

static EPG *bt_fast __P((BTREE *, const DBT *, const DBT *, int *));

/*
 * __BT_PUT -- Add a btree item to the tree.
 *
 * Parameters:
 *	dbp:	pointer to access method
 *	key:	key
 *	data:	data
 *	flag:	R_NOOVERWRITE
 *
 * Returns:
 *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key is already in the
 *	tree and R_NOOVERWRITE specified.
 */
int
__bt_put(dbp, key, data, flags)
	const DB *dbp;
	DBT *key;
	const DBT *data;
	u_int flags;
{
	BTREE *t;
	DBT tkey, tdata;
	EPG *e;
	PAGE *h;
	indx_t index, nxtindex;
	pgno_t pg;
	size_t nbytes;
	int dflags, exact, status;
	char *dest, db[NOVFLSIZE], kb[NOVFLSIZE];

	t = dbp->internal;

	/* Toss any page pinned across calls. */
	if (t->bt_pinned != NULL) {
		mpool_put(t->bt_mp, t->bt_pinned, 0);
		t->bt_pinned = NULL;
	}

	switch (flags) {
	case R_CURSOR:
		if (!ISSET(t, B_SEQINIT))
			goto einval;
		if (ISSET(t, B_DELCRSR))
			goto einval;
		break;
	case 0:
	case R_NOOVERWRITE:
		break;
	default:
einval:		errno = EINVAL;
		return (RET_ERROR);
	}

	if (ISSET(t, B_RDONLY)) {
		errno = EPERM;
		return (RET_ERROR);
	}

	/*
	 * If the key/data won't fit on a page, store it on indirect pages.
	 * Only store the key on the overflow page if it's too big after the
	 * data is on an overflow page.
	 *
	 * XXX
	 * If the insert fails later on, these pages aren't recovered.
	 */
	dflags = 0;
	if (key->size + data->size > t->bt_ovflsize) {
		if (key->size > t->bt_ovflsize) {
storekey:		if (__ovfl_put(t, key, &pg) == RET_ERROR)
				return (RET_ERROR);
			tkey.data = kb;
			tkey.size = NOVFLSIZE;
			memmove(kb, &pg, sizeof(pgno_t));
			memmove(kb + sizeof(pgno_t),
			    &key->size, sizeof(size_t));
			dflags |= P_BIGKEY;
			key = &tkey;
		}
		if (key->size + data->size > t->bt_ovflsize) {
			if (__ovfl_put(t, data, &pg) == RET_ERROR)
				return (RET_ERROR);
			tdata.data = db;
			tdata.size = NOVFLSIZE;
			memmove(db, &pg, sizeof(pgno_t));
			memmove(db + sizeof(pgno_t),
			    &data->size, sizeof(size_t));
			dflags |= P_BIGDATA;
			data = &tdata;
		}
		if (key->size + data->size > t->bt_ovflsize)
			goto storekey;
	}

	/* Replace the cursor. */
	if (flags == R_CURSOR) {
		if ((h = mpool_get(t->bt_mp, t->bt_bcursor.pgno, 0)) == NULL)
			return (RET_ERROR);
		index = t->bt_bcursor.index;
		goto delete;
	}

	/*
	 * Find the key to delete, or, the location at which to insert.  Bt_fast
	 * and __bt_search pin the returned page.
	 */
	if (t->bt_order == NOT || (e = bt_fast(t, key, data, &exact)) == NULL)
		if ((e = __bt_search(t, key, &exact)) == NULL)
			return (RET_ERROR);
	h = e->page;
	index = e->index;

	/*
	 * Add the specified key/data pair to the tree.  If an identical key
	 * is already in the tree, and R_NOOVERWRITE is set, an error is
	 * returned.  If R_NOOVERWRITE is not set, the key is either added (if
	 * duplicates are permitted) or an error is returned.
	 *
	 * Pages are split as required.
	 */
	switch (flags) {
	case R_NOOVERWRITE:
		if (!exact)
			break;
		/*
		 * One special case is if the cursor references the record and
		 * it's been flagged for deletion.  Then, we delete the record,
		 * leaving the cursor there -- this means that the inserted
		 * record will not be seen in a cursor scan.
		 */
		if (ISSET(t, B_DELCRSR) && t->bt_bcursor.pgno == h->pgno &&
		    t->bt_bcursor.index == index) {
			CLR(t, B_DELCRSR);
			goto delete;
		}
		mpool_put(t->bt_mp, h, 0);
		return (RET_SPECIAL);
	default:
		if (!exact || !ISSET(t, B_NODUPS))
			break;
delete:		if (__bt_dleaf(t, h, index) == RET_ERROR) {
			mpool_put(t->bt_mp, h, 0);
			return (RET_ERROR);
		}
		break;
	}

	/*
	 * If not enough room, or the user has put a ceiling on the number of
	 * keys permitted in the page, split the page.  The split code will
	 * insert the key and data and unpin the current page.  If inserting
	 * into the offset array, shift the pointers up.
	 */
	nbytes = NBLEAFDBT(key->size, data->size);
	if (h->upper - h->lower < nbytes + sizeof(indx_t)) {
		if ((status = __bt_split(t, h, key,
		    data, dflags, nbytes, index)) != RET_SUCCESS)
			return (status);
		goto success;
	}

	if (index < (nxtindex = NEXTINDEX(h)))
		memmove(h->linp + index + 1, h->linp + index,
		    (nxtindex - index) * sizeof(indx_t));
	h->lower += sizeof(indx_t);

	h->linp[index] = h->upper -= nbytes;
	dest = (char *)h + h->upper;
	WR_BLEAF(dest, key, data, dflags);

	if (t->bt_order == NOT)
		if (h->nextpg == P_INVALID) {
			if (index == NEXTINDEX(h) - 1) {
				t->bt_order = FORWARD;
				t->bt_last.index = index;
				t->bt_last.pgno = h->pgno;
			}
		} else if (h->prevpg == P_INVALID) {
			if (index == 0) {
				t->bt_order = BACK;
				t->bt_last.index = 0;
				t->bt_last.pgno = h->pgno;
			}
		}

	mpool_put(t->bt_mp, h, MPOOL_DIRTY);

success:
	if (flags == R_SETCURSOR) {
		t->bt_bcursor.pgno = e->page->pgno;
		t->bt_bcursor.index = e->index;
	}
	SET(t, B_MODIFIED);
	return (RET_SUCCESS);
}

#ifdef STATISTICS
u_long bt_cache_hit, bt_cache_miss;
#endif

/*
 * BT_FAST -- Do a quick check for sorted data.
 *
 * Parameters:
 *	t:	tree
 *	key:	key to insert
 *
 * Returns:
 * 	EPG for new record or NULL if not found.
 */
static EPG *
bt_fast(t, key, data, exactp)
	BTREE *t;
	const DBT *key, *data;
	int *exactp;
{
	PAGE *h;
	size_t nbytes;
	int cmp;

	if ((h = mpool_get(t->bt_mp, t->bt_last.pgno, 0)) == NULL) {
		t->bt_order = NOT;
		return (NULL);
	}
	t->bt_cur.page = h;
	t->bt_cur.index = t->bt_last.index;

	/*
	 * If won't fit in this page or have too many keys in this page, have
	 * to search to get split stack.
	 */
	nbytes = NBLEAFDBT(key->size, data->size);
	if (h->upper - h->lower < nbytes + sizeof(indx_t))
		goto miss;

	if (t->bt_order == FORWARD) {
		if (t->bt_cur.page->nextpg != P_INVALID)
			goto miss;
		if (t->bt_cur.index != NEXTINDEX(h) - 1)
			goto miss;
		if ((cmp = __bt_cmp(t, key, &t->bt_cur)) < 0)
			goto miss;
		t->bt_last.index = cmp ? ++t->bt_cur.index : t->bt_cur.index;
	} else {
		if (t->bt_cur.page->prevpg != P_INVALID)
			goto miss;
		if (t->bt_cur.index != 0)
			goto miss;
		if ((cmp = __bt_cmp(t, key, &t->bt_cur)) > 0)
			goto miss;
		t->bt_last.index = 0;
	}
	*exactp = cmp == 0;
#ifdef STATISTICS
	++bt_cache_hit;
#endif
	return (&t->bt_cur);

miss:
#ifdef STATISTICS
	++bt_cache_miss;
#endif
	t->bt_order = NOT;
	mpool_put(t->bt_mp, h, 0);
	return (NULL);
}
Commit	Line	Data
e9ce8d39 A	1	/*
	2	* Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
734aad71	6	* Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
e9ce8d39	7	*
734aad71 A	8	* This file contains Original Code and/or Modifications of Original Code
	9	* as defined in and that are subject to the Apple Public Source License
	10	* Version 2.0 (the 'License'). You may not use this file except in
	11	* compliance with the License. Please obtain a copy of the License at
	12	* http://www.opensource.apple.com/apsl/ and read it before using this
	13	* file.
	14	*
	15	* The Original Code and all software distributed under the License are
	16	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
e9ce8d39 A	17	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
e9ce8d39 A	18	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
734aad71 A	19	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	20	* Please see the License for the specific language governing rights and
	21	* limitations under the License.
e9ce8d39 A	22	*
	23	* @APPLE_LICENSE_HEADER_END@
	24	*/
	25	/*
	26	* Copyright (c) 1990, 1993
	27	* The Regents of the University of California. All rights reserved.
	28	*
	29	* This code is derived from software contributed to Berkeley by
	30	* Mike Olson.
	31	*
	32	* Redistribution and use in source and binary forms, with or without
	33	* modification, are permitted provided that the following conditions
	34	* are met:
	35	* 1. Redistributions of source code must retain the above copyright
	36	* notice, this list of conditions and the following disclaimer.
	37	* 2. Redistributions in binary form must reproduce the above copyright
	38	* notice, this list of conditions and the following disclaimer in the
	39	* documentation and/or other materials provided with the distribution.
	40	* 3. All advertising materials mentioning features or use of this software
	41	* must display the following acknowledgement:
	42	* This product includes software developed by the University of
	43	* California, Berkeley and its contributors.
	44	* 4. Neither the name of the University nor the names of its contributors
	45	* may be used to endorse or promote products derived from this software
	46	* without specific prior written permission.
	47	*
	48	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	49	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	50	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	51	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	52	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	53	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	54	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	55	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	56	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	57	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	58	* SUCH DAMAGE.
	59	*/
	60
	61
	62	#include <sys/types.h>
	63
	64	#include <errno.h>
	65	#include <stdio.h>
	66	#include <stdlib.h>
	67	#include <string.h>
	68
	69	#include <db.h>
	70	#include "btree.h"
	71
	72	static EPG bt_fast __P((BTREE , const DBT , const DBT , int *));
	73
	74	/*
	75	* __BT_PUT -- Add a btree item to the tree.
	76	*
	77	* Parameters:
	78	* dbp: pointer to access method
	79	* key: key
	80	* data: data
	81	* flag: R_NOOVERWRITE
	82	*
	83	* Returns:
	84	* RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key is already in the
	85	* tree and R_NOOVERWRITE specified.
86	*/
87	int
88	__bt_put(dbp, key, data, flags)
89	const DB *dbp;
90	DBT *key;
91	const DBT *data;
92	u_int flags;
93	{
94	BTREE *t;
95	DBT tkey, tdata;
96	EPG *e;
97	PAGE *h;
98	indx_t index, nxtindex;
99	pgno_t pg;
100	size_t nbytes;
101	int dflags, exact, status;
102	char *dest, db[NOVFLSIZE], kb[NOVFLSIZE];
103
104	t = dbp->internal;
105
106	/* Toss any page pinned across calls. */
107	if (t->bt_pinned != NULL) {
108	mpool_put(t->bt_mp, t->bt_pinned, 0);
109	t->bt_pinned = NULL;
110	}
111
112	switch (flags) {
113	case R_CURSOR:
114	if (!ISSET(t, B_SEQINIT))
115	goto einval;
116	if (ISSET(t, B_DELCRSR))
117	goto einval;
118	break;
119	case 0:
120	case R_NOOVERWRITE:
121	break;
122	default:
123	einval: errno = EINVAL;
124	return (RET_ERROR);
125	}
126
127	if (ISSET(t, B_RDONLY)) {
128	errno = EPERM;
129	return (RET_ERROR);
130	}
131
132	/*
133	* If the key/data won't fit on a page, store it on indirect pages.
134	* Only store the key on the overflow page if it's too big after the
135	* data is on an overflow page.
136	*
137	* XXX
138	* If the insert fails later on, these pages aren't recovered.
139	*/
140	dflags = 0;
141	if (key->size + data->size > t->bt_ovflsize) {
142	if (key->size > t->bt_ovflsize) {
143	storekey: if (__ovfl_put(t, key, &pg) == RET_ERROR)
144	return (RET_ERROR);
145	tkey.data = kb;
146	tkey.size = NOVFLSIZE;
147	memmove(kb, &pg, sizeof(pgno_t));
148	memmove(kb + sizeof(pgno_t),
149	&key->size, sizeof(size_t));
150	dflags \|= P_BIGKEY;
151	key = &tkey;
152	}
153	if (key->size + data->size > t->bt_ovflsize) {
154	if (__ovfl_put(t, data, &pg) == RET_ERROR)
155	return (RET_ERROR);
156	tdata.data = db;
157	tdata.size = NOVFLSIZE;
158	memmove(db, &pg, sizeof(pgno_t));
159	memmove(db + sizeof(pgno_t),
160	&data->size, sizeof(size_t));
161	dflags \|= P_BIGDATA;
162	data = &tdata;
163	}
164	if (key->size + data->size > t->bt_ovflsize)
165	goto storekey;
166	}
167
168	/* Replace the cursor. */
169	if (flags == R_CURSOR) {
170	if ((h = mpool_get(t->bt_mp, t->bt_bcursor.pgno, 0)) == NULL)
171	return (RET_ERROR);
172	index = t->bt_bcursor.index;
173	goto delete;
174	}
175
176	/*
177	* Find the key to delete, or, the location at which to insert. Bt_fast
178	* and __bt_search pin the returned page.
179	*/
180	if (t->bt_order == NOT \|\| (e = bt_fast(t, key, data, &exact)) == NULL)
181	if ((e = __bt_search(t, key, &exact)) == NULL)
182	return (RET_ERROR);
183	h = e->page;
184	index = e->index;
185
186	/*
187	* Add the specified key/data pair to the tree. If an identical key
188	* is already in the tree, and R_NOOVERWRITE is set, an error is
189	* returned. If R_NOOVERWRITE is not set, the key is either added (if
190	* duplicates are permitted) or an error is returned.
191	*
192	* Pages are split as required.
193	*/
194	switch (flags) {
195	case R_NOOVERWRITE:
196	if (!exact)
197	break;
198	/*
199	* One special case is if the cursor references the record and
200	* it's been flagged for deletion. Then, we delete the record,
201	* leaving the cursor there -- this means that the inserted
202	* record will not be seen in a cursor scan.
203	*/
204	if (ISSET(t, B_DELCRSR) && t->bt_bcursor.pgno == h->pgno &&
205	t->bt_bcursor.index == index) {
206	CLR(t, B_DELCRSR);
207	goto delete;
208	}
209	mpool_put(t->bt_mp, h, 0);
210	return (RET_SPECIAL);
211	default:
212	if (!exact \|\| !ISSET(t, B_NODUPS))
213	break;
214	delete: if (__bt_dleaf(t, h, index) == RET_ERROR) {
215	mpool_put(t->bt_mp, h, 0);
216	return (RET_ERROR);
217	}
218	break;
219	}
220
221	/*
222	* If not enough room, or the user has put a ceiling on the number of
223	* keys permitted in the page, split the page. The split code will
224	* insert the key and data and unpin the current page. If inserting
225	* into the offset array, shift the pointers up.
226	*/
227	nbytes = NBLEAFDBT(key->size, data->size);
228	if (h->upper - h->lower < nbytes + sizeof(indx_t)) {
229	if ((status = __bt_split(t, h, key,
230	data, dflags, nbytes, index)) != RET_SUCCESS)
231	return (status);
232	goto success;
233	}
234
235	if (index < (nxtindex = NEXTINDEX(h)))
236	memmove(h->linp + index + 1, h->linp + index,
237	(nxtindex - index) * sizeof(indx_t));
238	h->lower += sizeof(indx_t);
239
240	h->linp[index] = h->upper -= nbytes;
241	dest = (char *)h + h->upper;
242	WR_BLEAF(dest, key, data, dflags);
243
244	if (t->bt_order == NOT)
245	if (h->nextpg == P_INVALID) {
246	if (index == NEXTINDEX(h) - 1) {
247	t->bt_order = FORWARD;
248	t->bt_last.index = index;
249	t->bt_last.pgno = h->pgno;
250	}
251	} else if (h->prevpg == P_INVALID) {
252	if (index == 0) {
253	t->bt_order = BACK;
254	t->bt_last.index = 0;
255	t->bt_last.pgno = h->pgno;
256	}
257	}
258
259	mpool_put(t->bt_mp, h, MPOOL_DIRTY);
260
261	success:
262	if (flags == R_SETCURSOR) {
263	t->bt_bcursor.pgno = e->page->pgno;
264	t->bt_bcursor.index = e->index;
265	}
266	SET(t, B_MODIFIED);
267	return (RET_SUCCESS);
268	}
269
270	#ifdef STATISTICS
271	u_long bt_cache_hit, bt_cache_miss;
272	#endif
273
274	/*
275	* BT_FAST -- Do a quick check for sorted data.
276	*
277	* Parameters:
278	* t: tree
279	* key: key to insert
280	*
281	* Returns:
282	* EPG for new record or NULL if not found.
283	*/
284	static EPG *
285	bt_fast(t, key, data, exactp)
286	BTREE *t;
287	const DBT key, data;
288	int *exactp;
289	{
290	PAGE *h;
291	size_t nbytes;
292	int cmp;
293
294	if ((h = mpool_get(t->bt_mp, t->bt_last.pgno, 0)) == NULL) {
295	t->bt_order = NOT;
296	return (NULL);
297	}
298	t->bt_cur.page = h;
299	t->bt_cur.index = t->bt_last.index;
300
301	/*
302	* If won't fit in this page or have too many keys in this page, have
303	* to search to get split stack.
304	*/
305	nbytes = NBLEAFDBT(key->size, data->size);
306	if (h->upper - h->lower < nbytes + sizeof(indx_t))
307	goto miss;
308
309	if (t->bt_order == FORWARD) {
310	if (t->bt_cur.page->nextpg != P_INVALID)
311	goto miss;
312	if (t->bt_cur.index != NEXTINDEX(h) - 1)
313	goto miss;
314	if ((cmp = __bt_cmp(t, key, &t->bt_cur)) < 0)
315	goto miss;
316	t->bt_last.index = cmp ? ++t->bt_cur.index : t->bt_cur.index;
317	} else {
318	if (t->bt_cur.page->prevpg != P_INVALID)
319	goto miss;
320	if (t->bt_cur.index != 0)
321	goto miss;
322	if ((cmp = __bt_cmp(t, key, &t->bt_cur)) > 0)
323	goto miss;
324	t->bt_last.index = 0;
325	}
326	*exactp = cmp == 0;
327	#ifdef STATISTICS
328	++bt_cache_hit;
329	#endif
330	return (&t->bt_cur);
331
332	miss:
333	#ifdef STATISTICS
334	++bt_cache_miss;
335	#endif
336	t->bt_order = NOT;
337	mpool_put(t->bt_mp, h, 0);
338	return (NULL);
339	}