示例#1
0
文件: rec_open.c 项目: Hooman3/minix
DB *
__rec_open(const char *fname, int flags, mode_t mode, const RECNOINFO *openinfo,
    int dflags)
{
	BTREE *t;
	BTREEINFO btopeninfo;
	DB *dbp;
	PAGE *h;
	struct stat sb;
	int rfd = -1;	/* pacify gcc */
	int sverrno;

	dbp = NULL;
	/* Open the user's file -- if this fails, we're done. */
	if (fname != NULL) {
		if ((rfd = __dbopen(fname, flags, mode, NULL)) == -1)
			return NULL;
	}

	/* Create a btree in memory (backed by disk). */
	if (openinfo) {
		if (openinfo->flags & ~(R_FIXEDLEN | R_NOKEY | R_SNAPSHOT))
			goto einval;
		btopeninfo.flags = 0;
		btopeninfo.cachesize = openinfo->cachesize;
		btopeninfo.maxkeypage = 0;
		btopeninfo.minkeypage = 0;
		btopeninfo.psize = openinfo->psize;
		btopeninfo.compare = NULL;
		btopeninfo.prefix = NULL;
		btopeninfo.lorder = openinfo->lorder;
		dbp = __bt_open(openinfo->bfname,
		    O_RDWR, S_IRUSR | S_IWUSR, &btopeninfo, dflags);
	} else
		dbp = __bt_open(NULL, O_RDWR, S_IRUSR | S_IWUSR, NULL, dflags);
	if (dbp == NULL)
		goto err;

	/*
	 * Some fields in the tree structure are recno specific.  Fill them
	 * in and make the btree structure look like a recno structure.  We
	 * don't change the bt_ovflsize value, it's close enough and slightly
	 * bigger.
	 */
	t = dbp->internal;
	if (openinfo) {
		if (openinfo->flags & R_FIXEDLEN) {
			F_SET(t, R_FIXLEN);
			t->bt_reclen = openinfo->reclen;
			if (t->bt_reclen == 0)
				goto einval;
		}
		t->bt_bval = openinfo->bval;
	} else
		t->bt_bval = '\n';

	F_SET(t, R_RECNO);
	if (fname == NULL)
		F_SET(t, R_EOF | R_INMEM);
	else
		t->bt_rfd = rfd;

	if (fname != NULL) {
		/*
		 * In 4.4BSD, stat(2) returns true for ISSOCK on pipes.
		 * Unfortunately, that's not portable, so we use lseek
		 * and check the errno values.
		 */
		errno = 0;
		if (lseek(rfd, (off_t)0, SEEK_CUR) == -1 && errno == ESPIPE) {
			switch (flags & O_ACCMODE) {
			case O_RDONLY:
				F_SET(t, R_RDONLY);
				break;
			default:
				goto einval;
			}
slow:			if ((t->bt_rfp = fdopen(rfd, "r")) == NULL)
				goto err;
			F_SET(t, R_CLOSEFP);
			t->bt_irec =
			    F_ISSET(t, R_FIXLEN) ? __rec_fpipe : __rec_vpipe;
		} else {
			switch (flags & O_ACCMODE) {
			case O_RDONLY:
				F_SET(t, R_RDONLY);
				break;
			case O_RDWR:
				break;
			default:
				goto einval;
			}

			if (fstat(rfd, &sb))
				goto err;
			/*
			 * Kluge -- we'd like to test to see if the file is too
			 * big to mmap.  Since, we don't know what size or type
			 * off_t's or size_t's are, what the largest unsigned
			 * integral type is, or what random insanity the local
			 * C compiler will perpetrate, doing the comparison in
			 * a portable way is flatly impossible.  Hope that mmap
			 * fails if the file is too large.
			 */
			if (sb.st_size == 0)
				F_SET(t, R_EOF);
			else {
#ifdef MMAP_NOT_AVAILABLE
				/*
				 * XXX
				 * Mmap doesn't work correctly on many current
				 * systems.  In particular, it can fail subtly,
				 * with cache coherency problems.  Don't use it
				 * for now.
				 */
				t->bt_msize = sb.st_size;
				if ((t->bt_smap = mmap(NULL, t->bt_msize,
				    PROT_READ, MAP_FILE | MAP_PRIVATE, rfd,
				    (off_t)0)) == (caddr_t)-1)
					goto slow;
				t->bt_cmap = t->bt_smap;
				t->bt_emap = t->bt_smap + sb.st_size;
				t->bt_irec = F_ISSET(t, R_FIXLEN) ?
				    __rec_fmap : __rec_vmap;
				F_SET(t, R_MEMMAPPED);
#else
				goto slow;
#endif
			}
		}
	}

	/* Use the recno routines. */
	dbp->close = __rec_close;
	dbp->del = __rec_delete;
	dbp->fd = __rec_fd;
	dbp->get = __rec_get;
	dbp->put = __rec_put;
	dbp->seq = __rec_seq;
	dbp->sync = __rec_sync;

	/* If the root page was created, reset the flags. */
	if ((h = mpool_get(t->bt_mp, P_ROOT, 0)) == NULL)
		goto err;
	if ((h->flags & P_TYPE) == P_BLEAF) {
		F_CLR(h, P_TYPE);
		F_SET(h, P_RLEAF);
		mpool_put(t->bt_mp, h, MPOOL_DIRTY);
	} else
		mpool_put(t->bt_mp, h, 0);

	if (openinfo && openinfo->flags & R_SNAPSHOT &&
	    !F_ISSET(t, R_EOF | R_INMEM) &&
	    t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
                goto err;
	return (dbp);

einval:	errno = EINVAL;
err:	sverrno = errno;
	if (dbp != NULL)
		(void)__bt_close(dbp);
	if (fname != NULL)
		(void)close(rfd);
	errno = sverrno;
	return (NULL);
}
示例#2
0
/*
 * __REC_SYNC -- sync the recno tree to disk.
 *
 * Parameters:
 *	dbp:	pointer to access method
 *
 * Returns:
 *	RET_SUCCESS, RET_ERROR.
 */
int
__rec_sync(const DB *dbp, u_int flags)
{
	struct iovec iov[2];
	BTREE *t;
	DBT data, key;
	off_t off;
	recno_t scursor, trec;
	int status;

	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;
	}

	if (flags == R_RECNOSYNC)
		return (__bt_sync(dbp, 0));

	if (F_ISSET(t, R_RDONLY | R_INMEM) || !F_ISSET(t, R_MODIFIED))
		return (RET_SUCCESS);

	/* Read any remaining records into the tree. */
	if (!F_ISSET(t, R_EOF) && t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
		return (RET_ERROR);

	/* Rewind the file descriptor. */
	if (lseek(t->bt_rfd, (off_t)0, SEEK_SET) != 0)
		return (RET_ERROR);

	/* Save the cursor. */
	scursor = t->bt_cursor.rcursor;

	key.size = sizeof(recno_t);
	key.data = &trec;

	if (F_ISSET(t, R_FIXLEN)) {
		/*
		 * We assume that fixed length records are all fixed length.
		 * Any that aren't are either EINVAL'd or corrected by the
		 * record put code.
		 */
		status = (dbp->seq)(dbp, &key, &data, R_FIRST);
		while (status == RET_SUCCESS) {
			if (_write(t->bt_rfd, data.data, data.size) !=
			    (ssize_t)data.size)
				return (RET_ERROR);
			status = (dbp->seq)(dbp, &key, &data, R_NEXT);
		}
	} else {
		iov[1].iov_base = &t->bt_bval;
		iov[1].iov_len = 1;

		status = (dbp->seq)(dbp, &key, &data, R_FIRST);
		while (status == RET_SUCCESS) {
			iov[0].iov_base = data.data;
			iov[0].iov_len = data.size;
			if (_writev(t->bt_rfd, iov, 2) != (ssize_t)(data.size + 1))
				return (RET_ERROR);
			status = (dbp->seq)(dbp, &key, &data, R_NEXT);
		}
	}

	/* Restore the cursor. */
	t->bt_cursor.rcursor = scursor;

	if (status == RET_ERROR)
		return (RET_ERROR);
	if ((off = lseek(t->bt_rfd, (off_t)0, SEEK_CUR)) == -1)
		return (RET_ERROR);
	if (ftruncate(t->bt_rfd, off))
		return (RET_ERROR);
	F_CLR(t, R_MODIFIED);
	return (RET_SUCCESS);
}
示例#3
0
/*
 * __bt_curdel --
 *	Delete the cursor.
 *
 * Parameters:
 *	t:	tree
 *    key:	referenced key (or NULL)
 *	h:	page
 *    idx:	index on page to delete
 *
 * Returns:
 *	RET_SUCCESS, RET_ERROR.
 */
static int
__bt_curdel(BTREE *t, const DBT *key, PAGE *h, u_int idx)
{
	CURSOR *c;
	EPG e;
	PAGE *pg;
	int curcopy, status;

	/*
	 * If there are duplicates, move forward or backward to one.
	 * Otherwise, copy the key into the cursor area.
	 */
	c = &t->bt_cursor;
	F_CLR(c, CURS_AFTER | CURS_BEFORE | CURS_ACQUIRE);

	curcopy = 0;
	if (!F_ISSET(t, B_NODUPS)) {
		/*
		 * We're going to have to do comparisons.  If we weren't
		 * provided a copy of the key, i.e. the user is deleting
		 * the current cursor position, get one.
		 */
		if (key == NULL) {
			e.page = h;
			e.index = idx;
			if ((status = __bt_ret(t, &e,
			    &c->key, &c->key, NULL, NULL, 1)) != RET_SUCCESS)
				return (status);
			curcopy = 1;
			key = &c->key;
		}
		/* Check previous key, if not at the beginning of the page. */
		if (idx > 0) {
			e.page = h;
			e.index = idx - 1;
			if (__bt_cmp(t, key, &e) == 0) {
				F_SET(c, CURS_BEFORE);
				goto dup2;
			}
		}
		/* Check next key, if not at the end of the page. */
		if (idx < NEXTINDEX(h) - 1) {
			e.page = h;
			e.index = idx + 1;
			if (__bt_cmp(t, key, &e) == 0) {
				F_SET(c, CURS_AFTER);
				goto dup2;
			}
		}
		/* Check previous key if at the beginning of the page. */
		if (idx == 0 && h->prevpg != P_INVALID) {
			if ((pg = mpool_get(t->bt_mp, h->prevpg, 0)) == NULL)
				return (RET_ERROR);
			e.page = pg;
			e.index = NEXTINDEX(pg) - 1;
			if (__bt_cmp(t, key, &e) == 0) {
				F_SET(c, CURS_BEFORE);
				goto dup1;
			}
			mpool_put(t->bt_mp, pg, 0);
		}
		/* Check next key if at the end of the page. */
		if (idx == NEXTINDEX(h) - 1 && h->nextpg != P_INVALID) {
			if ((pg = mpool_get(t->bt_mp, h->nextpg, 0)) == NULL)
				return (RET_ERROR);
			e.page = pg;
			e.index = 0;
			if (__bt_cmp(t, key, &e) == 0) {
				F_SET(c, CURS_AFTER);
dup1:				mpool_put(t->bt_mp, pg, 0);
dup2:				c->pg.pgno = e.page->pgno;
				c->pg.index = e.index;
				return (RET_SUCCESS);
			}
			mpool_put(t->bt_mp, pg, 0);
		}
	}
	e.page = h;
	e.index = idx;
	if (curcopy || (status =
	    __bt_ret(t, &e, &c->key, &c->key, NULL, NULL, 1)) == RET_SUCCESS) {
		F_SET(c, CURS_ACQUIRE);
		return (RET_SUCCESS);
	}
	return (status);
}
示例#4
0
/*
 * __bt_delete
 *	Delete the item(s) referenced by a key.
 *
 * Return RET_SPECIAL if the key is not found.
 */
int
__bt_delete(const DB *dbp, const DBT *key, u_int flags)
{
	BTREE *t;
	CURSOR *c;
	PAGE *h;
	int status;

	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;
	}

	/* Check for change to a read-only tree. */
	if (F_ISSET(t, B_RDONLY)) {
		errno = EPERM;
		return (RET_ERROR);
	}

	switch (flags) {
	case 0:
		status = __bt_bdelete(t, key);
		break;
	case R_CURSOR:
		/*
		 * If flags is R_CURSOR, delete the cursor.  Must already
		 * have started a scan and not have already deleted it.
		 */
		c = &t->bt_cursor;
		if (F_ISSET(c, CURS_INIT)) {
			if (F_ISSET(c, CURS_ACQUIRE | CURS_AFTER | CURS_BEFORE))
				return (RET_SPECIAL);
			if ((h = mpool_get(t->bt_mp, c->pg.pgno, 0)) == NULL)
				return (RET_ERROR);

			/*
			 * If the page is about to be emptied, we'll need to
			 * delete it, which means we have to acquire a stack.
			 */
			if (NEXTINDEX(h) == 1)
				if (__bt_stkacq(t, &h, &t->bt_cursor))
					return (RET_ERROR);

			status = __bt_dleaf(t, NULL, h, c->pg.index);

			if (NEXTINDEX(h) == 0 && status == RET_SUCCESS) {
				if (__bt_pdelete(t, h))
					return (RET_ERROR);
			} else
				mpool_put(t->bt_mp,
				    h, status == RET_SUCCESS ? MPOOL_DIRTY : 0);
			break;
		}
		/* FALLTHROUGH */
	default:
		errno = EINVAL;
		return (RET_ERROR);
	}
	if (status == RET_SUCCESS)
		F_SET(t, B_MODIFIED);
	return (status);
}
示例#5
0
/*
 * __bt_search --
 *	Search a btree for a key.
 *
 * Parameters:
 *	t:	tree to search
 *	key:	key to find
 *	exactp:	pointer to exact match flag
 *
 * Returns:
 *	The EPG for matching record, if any, or the EPG for the location
 *	of the key, if it were inserted into the tree, is entered into
 *	the bt_cur field of the tree.  A pointer to the field is returned.
 */
EPG *
__bt_search(BTREE *t, const DBT *key, int *exactp)
{
	PAGE *h;
	indx_t base, idx, lim;
	pgno_t pg;
	int cmp;

	BT_CLR(t);
	for (pg = P_ROOT;;) {
		if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
			return (NULL);

		/* Do a binary search on the current page. */
		t->bt_cur.page = h;
		for (base = 0, lim = NEXTINDEX(h); lim; lim >>= 1) {
			t->bt_cur.index = idx = base + (lim >> 1);
			if ((cmp = __bt_cmp(t, key, &t->bt_cur)) == 0) {
				if (h->flags & P_BLEAF) {
					*exactp = 1;
					return (&t->bt_cur);
				}
				goto next;
			}
			if (cmp > 0) {
				base = idx + 1;
				--lim;
			}
		}

		/*
		 * If it's a leaf page, we're almost done.  If no duplicates
		 * are allowed, or we have an exact match, we're done.  Else,
		 * it's possible that there were matching keys on this page,
		 * which later deleted, and we're on a page with no matches
		 * while there are matches on other pages.  If at the start or
		 * end of a page, check the adjacent page.
		 */
		if (h->flags & P_BLEAF) {
			if (!F_ISSET(t, B_NODUPS)) {
				if (base == 0 &&
				    h->prevpg != P_INVALID &&
				    __bt_sprev(t, h, key, exactp))
					return (&t->bt_cur);
				if (base == NEXTINDEX(h) &&
				    h->nextpg != P_INVALID &&
				    __bt_snext(t, h, key, exactp))
					return (&t->bt_cur);
			}
			*exactp = 0;
			t->bt_cur.index = base;
			return (&t->bt_cur);
		}

		/*
		 * No match found.  Base is the smallest index greater than
		 * key and may be zero or a last + 1 index.  If it's non-zero,
		 * decrement by one, and record the internal page which should
		 * be a parent page for the key.  If a split later occurs, the
		 * inserted page will be to the right of the saved page.
		 */
		idx = base ? base - 1 : base;

next:		BT_PUSH(t, h->pgno, idx);
		pg = GETBINTERNAL(h, idx)->pgno;
		mpool_put(t->bt_mp, h, 0);
	}
}
示例#6
0
/*
 * __bt_pdelete --
 *	Delete a single page from the tree.
 *
 * Parameters:
 *	t:	tree
 *	h:	leaf page
 *
 * Returns:
 *	RET_SUCCESS, RET_ERROR.
 *
 * Side-effects:
 *	mpool_put's the page
 */
static int
__bt_pdelete(BTREE *t, PAGE *h)
{
	BINTERNAL *bi;
	PAGE *pg;
	EPGNO *parent;
	indx_t cnt, idx, *ip, offset;
	u_int32_t nksize;
	char *from;

	/*
	 * Walk the parent page stack -- a LIFO stack of the pages that were
	 * traversed when we searched for the page where the delete occurred.
	 * Each stack entry is a page number and a page index offset.  The
	 * offset is for the page traversed on the search.  We've just deleted
	 * a page, so we have to delete the key from the parent page.
	 *
	 * If the delete from the parent page makes it empty, this process may
	 * continue all the way up the tree.  We stop if we reach the root page
	 * (which is never deleted, it's just not worth the effort) or if the
	 * delete does not empty the page.
	 */
	while ((parent = BT_POP(t)) != NULL) {
		/* Get the parent page. */
		if ((pg = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
			return (RET_ERROR);

		idx = parent->index;
		bi = GETBINTERNAL(pg, idx);

		/* Free any overflow pages. */
		if (bi->flags & P_BIGKEY &&
		    __ovfl_delete(t, bi->bytes) == RET_ERROR) {
			mpool_put(t->bt_mp, pg, 0);
			return (RET_ERROR);
		}

		/*
		 * Free the parent if it has only the one key and it's not the
		 * root page. If it's the rootpage, turn it back into an empty
		 * leaf page.
		 */
		if (NEXTINDEX(pg) == 1) {
			if (pg->pgno == P_ROOT) {
				pg->lower = BTDATAOFF;
				pg->upper = t->bt_psize;
				pg->flags = P_BLEAF;
			} else {
				if (__bt_relink(t, pg) || __bt_free(t, pg))
					return (RET_ERROR);
				continue;
			}
		} else {
			/* Pack remaining key items at the end of the page. */
			nksize = NBINTERNAL(bi->ksize);
			from = (char *)pg + pg->upper;
			memmove(from + nksize, from, (char *)bi - from);
			pg->upper += nksize;

			/* Adjust indices' offsets, shift the indices down. */
			offset = pg->linp[idx];
			for (cnt = idx, ip = &pg->linp[0]; cnt--; ++ip)
				if (ip[0] < offset)
					ip[0] += nksize;
			for (cnt = NEXTINDEX(pg) - idx; --cnt; ++ip)
				ip[0] = ip[1] < offset ? ip[1] + nksize : ip[1];
			pg->lower -= sizeof(indx_t);
		}

		mpool_put(t->bt_mp, pg, MPOOL_DIRTY);
		break;
	}

	/* Free the leaf page, as long as it wasn't the root. */
	if (h->pgno == P_ROOT) {
		mpool_put(t->bt_mp, h, MPOOL_DIRTY);
		return (RET_SUCCESS);
	}
	return (__bt_relink(t, h) || __bt_free(t, h));
}
示例#7
0
/*
 * __REC_SEARCH -- Search a btree for a key.
 *
 * Parameters:
 *	t:	tree to search
 *	recno:	key to find
 *	op: 	search operation
 *
 * Returns:
 *	EPG for matching record, if any, or the EPG for the location of the
 *	key, if it were inserted into the tree.
 *
 * Returns:
 *	The EPG for matching record, if any, or the EPG for the location
 *	of the key, if it were inserted into the tree, is entered into
 *	the bt_cur field of the tree.  A pointer to the field is returned.
 */
EPG *
__rec_search(BTREE *t, recno_t recno, enum SRCHOP op)
{
	indx_t idx;
	PAGE *h;
	EPGNO *parent;
	RINTERNAL *r;
	pgno_t pg;
	indx_t top;
	recno_t total;
	int sverrno;

	BT_CLR(t);
	for (pg = P_ROOT, total = 0;;) {
		if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
			goto err;
		if (h->flags & P_RLEAF) {
			t->bt_cur.page = h;
			t->bt_cur.index = recno - total;
			return (&t->bt_cur);
		}
		for (idx = 0, top = NEXTINDEX(h);;) {
			r = GETRINTERNAL(h, idx);
			if (++idx == top || total + r->nrecs > recno)
				break;
			total += r->nrecs;
		}

		BT_PUSH(t, pg, idx - 1);
		
		pg = r->pgno;
		switch (op) {
		case SDELETE:
			--GETRINTERNAL(h, (idx - 1))->nrecs;
			mpool_put(t->bt_mp, h, MPOOL_DIRTY);
			break;
		case SINSERT:
			++GETRINTERNAL(h, (idx - 1))->nrecs;
			mpool_put(t->bt_mp, h, MPOOL_DIRTY);
			break;
		case SEARCH:
			mpool_put(t->bt_mp, h, 0);
			break;
		}

	}
	/* Try and recover the tree. */
err:	sverrno = errno;
	if (op != SEARCH)
		while  ((parent = BT_POP(t)) != NULL) {
			if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
				break;
			if (op == SINSERT)
				--GETRINTERNAL(h, parent->index)->nrecs;
			else
				++GETRINTERNAL(h, parent->index)->nrecs;
                        mpool_put(t->bt_mp, h, MPOOL_DIRTY);
                }
	errno = sverrno;
	return (NULL);
}
示例#8
0
/*
 * __bt_seqset --
 *	Set the sequential scan to a specific key.
 *
 * Parameters:
 *	t:	tree
 *	ep:	storage for returned key
 *	key:	key for initial scan position
 *	flags:	R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV
 *
 * Side effects:
 *	Pins the page the cursor references.
 *
 * Returns:
 *	RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key.
 */
static int
__bt_seqset(BTREE *t, EPG *ep, DBT *key, int flags)
{
	PAGE *h;
	pgno_t pg;
	int exact;

	/*
	 * Find the first, last or specific key in the tree and point the
	 * cursor at it.  The cursor may not be moved until a new key has
	 * been found.
	 */
	switch (flags) {
	case R_CURSOR:				/* Keyed scan. */
		/*
		 * Find the first instance of the key or the smallest key
		 * which is greater than or equal to the specified key.
		 */
		if (key->data == NULL || key->size == 0) {
			errno = EINVAL;
			return (RET_ERROR);
		}
		return (__bt_first(t, key, ep, &exact));
	case R_FIRST:				/* First record. */
	case R_NEXT:
		/* Walk down the left-hand side of the tree. */
		for (pg = P_ROOT;;) {
			if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
				return (RET_ERROR);

			/* Check for an empty tree. */
			if (NEXTINDEX(h) == 0) {
				mpool_put(t->bt_mp, h, 0);
				return (RET_SPECIAL);
			}

			if (h->flags & (P_BLEAF | P_RLEAF))
				break;
			pg = GETBINTERNAL(h, 0)->pgno;
			mpool_put(t->bt_mp, h, 0);
		}
		ep->page = h;
		ep->index = 0;
		break;
	case R_LAST:				/* Last record. */
	case R_PREV:
		/* Walk down the right-hand side of the tree. */
		for (pg = P_ROOT;;) {
			if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
				return (RET_ERROR);

			/* Check for an empty tree. */
			if (NEXTINDEX(h) == 0) {
				mpool_put(t->bt_mp, h, 0);
				return (RET_SPECIAL);
			}

			if (h->flags & (P_BLEAF | P_RLEAF))
				break;
			pg = GETBINTERNAL(h, NEXTINDEX(h) - 1)->pgno;
			mpool_put(t->bt_mp, h, 0);
		}

		ep->page = h;
		ep->index = NEXTINDEX(h) - 1;
		break;
	}
	return (RET_SUCCESS);
}
示例#9
0
/*
 * __REC_IPUT -- Add a recno item to the tree.
 *
 * Parameters:
 *	t:	tree
 *	nrec:	record number
 *	data:	data
 *
 * Returns:
 *	RET_ERROR, RET_SUCCESS
 */
int
__rec_iput(BTREE *t, recno_t nrec, const DBT *data, u_int flags)
{
    DBT tdata;
    EPG *e;
    PAGE *h;
    indx_t idx, nxtindex;
    pgno_t pg;
    uint32_t nbytes;
    int dflags, status;
    char *dest, db[NOVFLSIZE];

    /*
     * If the data won't fit on a page, store it on indirect pages.
     *
     * XXX
     * If the insert fails later on, these pages aren't recovered.
     */
    if (data->size > t->bt_ovflsize) {
        if (__ovfl_put(t, data, &pg) == RET_ERROR)
            return (RET_ERROR);
        tdata.data = db;
        tdata.size = NOVFLSIZE;
        *(pgno_t *)(void *)db = pg;
        _DBFIT(data->size, uint32_t);
        *(uint32_t *)(void *)(db + sizeof(pgno_t)) =
            (uint32_t)data->size;
        dflags = P_BIGDATA;
        data = &tdata;
    } else
        dflags = 0;

    /* __rec_search pins the returned page. */
    if ((e = __rec_search(t, nrec,
                          nrec > t->bt_nrecs || flags == R_IAFTER || flags == R_IBEFORE ?
                          SINSERT : SEARCH)) == NULL)
        return (RET_ERROR);

    h = e->page;
    idx = e->index;

    /*
     * Add the specified key/data pair to the tree.  The R_IAFTER and
     * R_IBEFORE flags insert the key after/before the specified key.
     *
     * Pages are split as required.
     */
    switch (flags) {
    case R_IAFTER:
        ++idx;
        break;
    case R_IBEFORE:
        break;
    default:
        if (nrec < t->bt_nrecs &&
                __rec_dleaf(t, h, (uint32_t)idx) == RET_ERROR) {
            mpool_put(t->bt_mp, h, 0);
            return (RET_ERROR);
        }
        break;
    }

    /*
     * If not enough room, 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 = NRLEAFDBT(data->size);
    if ((uint32_t) (h->upper - h->lower) < nbytes + sizeof(indx_t)) {
        status = __bt_split(t, h, NULL, data, dflags, nbytes,
                            (uint32_t)idx);
        if (status == RET_SUCCESS)
            ++t->bt_nrecs;
        return (status);
    }

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

    h->linp[idx] = h->upper -= nbytes;
    dest = (char *)(void *)h + h->upper;
    WR_RLEAF(dest, data, dflags);

    ++t->bt_nrecs;
    F_SET(t, B_MODIFIED);
    mpool_put(t->bt_mp, h, MPOOL_DIRTY);

    return (RET_SUCCESS);
}
示例#10
0
/*
 * __REC_PUT -- Add a recno item to the tree.
 *
 * Parameters:
 *	dbp:	pointer to access method
 *	key:	key
 *	data:	data
 *	flag:	R_CURSOR, R_IAFTER, R_IBEFORE, R_NOOVERWRITE
 *
 * Returns:
 *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key is
 *	already in the tree and R_NOOVERWRITE specified.
 */
int
__rec_put(const DB *dbp, DBT *key, const DBT *data, u_int flags)
{
    BTREE *t;
    DBT fdata, tdata;
    recno_t nrec;
    int status;

    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;
    }

    /*
     * If using fixed-length records, and the record is long, return
     * EINVAL.  If it's short, pad it out.  Use the record data return
     * memory, it's only short-term.
     */
    if (F_ISSET(t, R_FIXLEN) && data->size != t->bt_reclen) {
        if (data->size > t->bt_reclen)
            goto einval;

        if (t->bt_rdata.size < t->bt_reclen) {
            t->bt_rdata.data = t->bt_rdata.data == NULL ?
                               malloc(t->bt_reclen) :
                               realloc(t->bt_rdata.data, t->bt_reclen);
            if (t->bt_rdata.data == NULL)
                return (RET_ERROR);
            t->bt_rdata.size = t->bt_reclen;
        }
        memmove(t->bt_rdata.data, data->data, data->size);
        memset((char *)t->bt_rdata.data + data->size,
               t->bt_bval, t->bt_reclen - data->size);
        fdata.data = t->bt_rdata.data;
        fdata.size = t->bt_reclen;
    } else {
        fdata.data = data->data;
        fdata.size = data->size;
    }

    switch (flags) {
    case R_CURSOR:
        if (!F_ISSET(&t->bt_cursor, CURS_INIT))
            goto einval;
        nrec = t->bt_cursor.rcursor;
        break;
    case R_SETCURSOR:
        if ((nrec = *(recno_t *)key->data) == 0)
            goto einval;
        break;
    case R_IAFTER:
        if ((nrec = *(recno_t *)key->data) == 0) {
            nrec = 1;
            flags = R_IBEFORE;
        }
        break;
    case 0:
    case R_IBEFORE:
        if ((nrec = *(recno_t *)key->data) == 0)
            goto einval;
        break;
    case R_NOOVERWRITE:
        if ((nrec = *(recno_t *)key->data) == 0)
            goto einval;
        if (nrec <= t->bt_nrecs)
            return (RET_SPECIAL);
        break;
    default:
einval:
        errno = EINVAL;
        return (RET_ERROR);
    }

    /*
     * Make sure that records up to and including the put record are
     * already in the database.  If skipping records, create empty ones.
     */
    if (nrec > t->bt_nrecs) {
        if (!F_ISSET(t, R_EOF | R_INMEM) &&
                t->bt_irec(t, nrec) == RET_ERROR)
            return (RET_ERROR);
        if (nrec > t->bt_nrecs + 1) {
            if (F_ISSET(t, R_FIXLEN)) {
                if ((tdata.data =
                            (void *)malloc(t->bt_reclen)) == NULL)
                    return (RET_ERROR);
                tdata.size = t->bt_reclen;
                memset(tdata.data, t->bt_bval, tdata.size);
            } else {
                tdata.data = NULL;
                tdata.size = 0;
            }
            while (nrec > t->bt_nrecs + 1)
                if (__rec_iput(t,
                               t->bt_nrecs, &tdata, 0) != RET_SUCCESS)
                    return (RET_ERROR);
            if (F_ISSET(t, R_FIXLEN))
                free(tdata.data);
        }
    }

    if ((status = __rec_iput(t, nrec - 1, &fdata, flags)) != RET_SUCCESS)
        return (status);

    if (flags == R_SETCURSOR)
        t->bt_cursor.rcursor = nrec;

    F_SET(t, R_MODIFIED);
    return (__rec_ret(t, NULL, nrec, key, NULL));
}
示例#11
0
/*
 * __BT_SPLIT -- Split the tree.
 *
 * Parameters:
 *	t:	tree
 *	sp:	page to split
 *	key:	key to insert
 *	data:	data to insert
 *	flags:	BIGKEY/BIGDATA flags
 *	ilen:	insert length
 *	skip:	index to leave open
 *
 * Returns:
 *	RET_ERROR, RET_SUCCESS
 */
int
__bt_split(BTREE *t, PAGE *sp, const DBT *key, const DBT *data, int flags,
    size_t ilen, u_int32_t argskip)
{
	BINTERNAL *bi;
	BLEAF *bl, *tbl;
	DBT a, b;
	EPGNO *parent;
	PAGE *h, *l, *r, *lchild, *rchild;
	indx_t nxtindex;
	u_int16_t skip;
	u_int32_t n, nbytes, nksize;
	int parentsplit;
	char *dest;

	/*
	 * Split the page into two pages, l and r.  The split routines return
	 * a pointer to the page into which the key should be inserted and with
	 * skip set to the offset which should be used.  Additionally, l and r
	 * are pinned.
	 */
	skip = argskip;
	h = sp->pgno == P_ROOT ?
	    bt_root(t, sp, &l, &r, &skip, ilen) :
	    bt_page(t, sp, &l, &r, &skip, ilen);
	if (h == NULL)
		return (RET_ERROR);

	/*
	 * Insert the new key/data pair into the leaf page.  (Key inserts
	 * always cause a leaf page to split first.)
	 */
	h->linp[skip] = h->upper -= ilen;
	dest = (char *)h + h->upper;
	if (F_ISSET(t, R_RECNO))
		WR_RLEAF(dest, data, flags)
	else
		WR_BLEAF(dest, key, data, flags)

	/* If the root page was split, make it look right. */
	if (sp->pgno == P_ROOT &&
	    (F_ISSET(t, R_RECNO) ?
	    bt_rroot(t, sp, l, r) : bt_broot(t, sp, l, r)) == RET_ERROR)
		goto err2;

	/*
	 * Now we walk the parent page stack -- a LIFO stack of the pages that
	 * were traversed when we searched for the page that split.  Each stack
	 * entry is a page number and a page index offset.  The offset is for
	 * the page traversed on the search.  We've just split a page, so we
	 * have to insert a new key into the parent page.
	 *
	 * If the insert into the parent page causes it to split, may have to
	 * continue splitting all the way up the tree.  We stop if the root
	 * splits or the page inserted into didn't have to split to hold the
	 * new key.  Some algorithms replace the key for the old page as well
	 * as the new page.  We don't, as there's no reason to believe that the
	 * first key on the old page is any better than the key we have, and,
	 * in the case of a key being placed at index 0 causing the split, the
	 * key is unavailable.
	 *
	 * There are a maximum of 5 pages pinned at any time.  We keep the left
	 * and right pages pinned while working on the parent.   The 5 are the
	 * two children, left parent and right parent (when the parent splits)
	 * and the root page or the overflow key page when calling bt_preserve.
	 * This code must make sure that all pins are released other than the
	 * root page or overflow page which is unlocked elsewhere.
	 */
	while ((parent = BT_POP(t)) != NULL) {
		lchild = l;
		rchild = r;

		/* Get the parent page. */
		if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
			goto err2;

		/*
		 * The new key goes ONE AFTER the index, because the split
		 * was to the right.
		 */
		skip = parent->index + 1;

		/*
		 * Calculate the space needed on the parent page.
		 *
		 * Prefix trees: space hack when inserting into BINTERNAL
		 * pages.  Retain only what's needed to distinguish between
		 * the new entry and the LAST entry on the page to its left.
		 * If the keys compare equal, retain the entire key.  Note,
		 * we don't touch overflow keys, and the entire key must be
		 * retained for the next-to-left most key on the leftmost
		 * page of each level, or the search will fail.  Applicable
		 * ONLY to internal pages that have leaf pages as children.
		 * Further reduction of the key between pairs of internal
		 * pages loses too much information.
		 */
		switch (rchild->flags & P_TYPE) {
		case P_BINTERNAL:
			bi = GETBINTERNAL(rchild, 0);
			nbytes = NBINTERNAL(bi->ksize);
			break;
		case P_BLEAF:
			bl = GETBLEAF(rchild, 0);
			nbytes = NBINTERNAL(bl->ksize);
			if (t->bt_pfx && !(bl->flags & P_BIGKEY) &&
			    (h->prevpg != P_INVALID || skip > 1)) {
				tbl = GETBLEAF(lchild, NEXTINDEX(lchild) - 1);
				a.size = tbl->ksize;
				a.data = tbl->bytes;
				b.size = bl->ksize;
				b.data = bl->bytes;
				nksize = t->bt_pfx(&a, &b);
				n = NBINTERNAL(nksize);
				if (n < nbytes) {
#ifdef STATISTICS
					bt_pfxsaved += nbytes - n;
#endif
					nbytes = n;
				} else
					nksize = 0;
			} else
				nksize = 0;
			break;
		case P_RINTERNAL:
		case P_RLEAF:
			nbytes = NRINTERNAL;
			break;
		default:
			abort();
		}

		/* Split the parent page if necessary or shift the indices. */
		if ((u_int32_t)(h->upper - h->lower) < nbytes + sizeof(indx_t)) {
			sp = h;
			h = h->pgno == P_ROOT ?
			    bt_root(t, h, &l, &r, &skip, nbytes) :
			    bt_page(t, h, &l, &r, &skip, nbytes);
			if (h == NULL)
				goto err1;
			parentsplit = 1;
		} else {
			if (skip < (nxtindex = NEXTINDEX(h)))
				memmove(h->linp + skip + 1, h->linp + skip,
				    (nxtindex - skip) * sizeof(indx_t));
			h->lower += sizeof(indx_t);
			parentsplit = 0;
		}

		/* Insert the key into the parent page. */
		switch (rchild->flags & P_TYPE) {
		case P_BINTERNAL:
			h->linp[skip] = h->upper -= nbytes;
			dest = (char *)h + h->linp[skip];
			memmove(dest, bi, nbytes);
			((BINTERNAL *)dest)->pgno = rchild->pgno;
			break;
		case P_BLEAF:
			h->linp[skip] = h->upper -= nbytes;
			dest = (char *)h + h->linp[skip];
			WR_BINTERNAL(dest, nksize ? nksize : bl->ksize,
			    rchild->pgno, bl->flags & P_BIGKEY);
			memmove(dest, bl->bytes, nksize ? nksize : bl->ksize);
			if (bl->flags & P_BIGKEY) {
				pgno_t pgno;
				memcpy(&pgno, bl->bytes, sizeof(pgno));
				if (bt_preserve(t, pgno) == RET_ERROR)
					goto err1;
			}
			break;
		case P_RINTERNAL:
			/*
			 * Update the left page count.  If split
			 * added at index 0, fix the correct page.
			 */
			if (skip > 0)
				dest = (char *)h + h->linp[skip - 1];
			else
				dest = (char *)l + l->linp[NEXTINDEX(l) - 1];
			((RINTERNAL *)dest)->nrecs = rec_total(lchild);
			((RINTERNAL *)dest)->pgno = lchild->pgno;

			/* Update the right page count. */
			h->linp[skip] = h->upper -= nbytes;
			dest = (char *)h + h->linp[skip];
			((RINTERNAL *)dest)->nrecs = rec_total(rchild);
			((RINTERNAL *)dest)->pgno = rchild->pgno;
			break;
		case P_RLEAF:
			/*
			 * Update the left page count.  If split
			 * added at index 0, fix the correct page.
			 */
			if (skip > 0)
				dest = (char *)h + h->linp[skip - 1];
			else
				dest = (char *)l + l->linp[NEXTINDEX(l) - 1];
			((RINTERNAL *)dest)->nrecs = NEXTINDEX(lchild);
			((RINTERNAL *)dest)->pgno = lchild->pgno;

			/* Update the right page count. */
			h->linp[skip] = h->upper -= nbytes;
			dest = (char *)h + h->linp[skip];
			((RINTERNAL *)dest)->nrecs = NEXTINDEX(rchild);
			((RINTERNAL *)dest)->pgno = rchild->pgno;
			break;
		default:
			abort();
		}

		/* Unpin the held pages. */
		if (!parentsplit) {
			mpool_put(t->bt_mp, h, MPOOL_DIRTY);
			break;
		}

		/* If the root page was split, make it look right. */
		if (sp->pgno == P_ROOT &&
		    (F_ISSET(t, R_RECNO) ?
		    bt_rroot(t, sp, l, r) : bt_broot(t, sp, l, r)) == RET_ERROR)
			goto err1;

		mpool_put(t->bt_mp, lchild, MPOOL_DIRTY);
		mpool_put(t->bt_mp, rchild, MPOOL_DIRTY);
	}

	/* Unpin the held pages. */
	mpool_put(t->bt_mp, l, MPOOL_DIRTY);
	mpool_put(t->bt_mp, r, MPOOL_DIRTY);

	/* Clear any pages left on the stack. */
	return (RET_SUCCESS);

	/*
	 * If something fails in the above loop we were already walking back
	 * up the tree and the tree is now inconsistent.  Nothing much we can
	 * do about it but release any memory we're holding.
	 */
err1:	mpool_put(t->bt_mp, lchild, MPOOL_DIRTY);
	mpool_put(t->bt_mp, rchild, MPOOL_DIRTY);

err2:	mpool_put(t->bt_mp, l, 0);
	mpool_put(t->bt_mp, r, 0);
	__dbpanic(t->bt_dbp);
	return (RET_ERROR);
}
示例#12
0
/*
 * BT_BROOT -- Fix up the btree root page after it has been split.
 *
 * Parameters:
 *	t:	tree
 *	h:	root page
 *	l:	left page
 *	r:	right page
 *
 * Returns:
 *	RET_ERROR, RET_SUCCESS
 */
static int
bt_broot(BTREE *t, PAGE *h, PAGE *l, PAGE *r)
{
	BINTERNAL *bi;
	BLEAF *bl;
	u_int32_t nbytes;
	char *dest;

	/*
	 * If the root page was a leaf page, change it into an internal page.
	 * We copy the key we split on (but not the key's data, in the case of
	 * a leaf page) to the new root page.
	 *
	 * The btree comparison code guarantees that the left-most key on any
	 * level of the tree is never used, so it doesn't need to be filled in.
	 */
	nbytes = NBINTERNAL(0);
	h->linp[0] = h->upper = t->bt_psize - nbytes;
	dest = (char *)h + h->upper;
	WR_BINTERNAL(dest, 0, l->pgno, 0);

	switch (h->flags & P_TYPE) {
	case P_BLEAF:
		bl = GETBLEAF(r, 0);
		nbytes = NBINTERNAL(bl->ksize);
		__PAST_END(h->linp, 1) = h->upper -= nbytes;
		dest = (char *)h + h->upper;
		WR_BINTERNAL(dest, bl->ksize, r->pgno, 0);
		memmove(dest, bl->bytes, bl->ksize);

		/*
		 * If the key is on an overflow page, mark the overflow chain
		 * so it isn't deleted when the leaf copy of the key is deleted.
		 */
	if (bl->flags & P_BIGKEY) {
			pgno_t pgno;
			memcpy(&pgno, bl->bytes, sizeof(pgno));
			if (bt_preserve(t, pgno) == RET_ERROR)
				return (RET_ERROR);
		}
		break;
	case P_BINTERNAL:
		bi = GETBINTERNAL(r, 0);
		nbytes = NBINTERNAL(bi->ksize);
		__PAST_END(h->linp, 1) = h->upper -= nbytes;
		dest = (char *)h + h->upper;
		memmove(dest, bi, nbytes);
		((BINTERNAL *)dest)->pgno = r->pgno;
		break;
	default:
		abort();
	}

	/* There are two keys on the page. */
	h->lower = BTDATAOFF + 2 * sizeof(indx_t);

	/* Unpin the root page, set to btree internal page. */
	h->flags &= ~P_TYPE;
	h->flags |= P_BINTERNAL;
	mpool_put(t->bt_mp, h, MPOOL_DIRTY);

	return (RET_SUCCESS);
}
示例#13
0
/*
 * BT_PAGE -- Split a non-root page of a btree.
 *
 * Parameters:
 *	t:	tree
 *	h:	root page
 *	lp:	pointer to left page pointer
 *	rp:	pointer to right page pointer
 *	skip:	pointer to index to leave open
 *	ilen:	insert length
 *
 * Returns:
 *	Pointer to page in which to insert or NULL on error.
 */
static PAGE *
bt_page(BTREE *t, PAGE *h, PAGE **lp, PAGE **rp, indx_t *skip, size_t ilen)
{
	PAGE *l, *r, *tp;
	pgno_t npg;

#ifdef STATISTICS
	++bt_split;
#endif
	/* Put the new right page for the split into place. */
	if ((r = __bt_new(t, &npg)) == NULL)
		return (NULL);
	r->pgno = npg;
	r->lower = BTDATAOFF;
	r->upper = t->bt_psize;
	r->nextpg = h->nextpg;
	r->prevpg = h->pgno;
	r->flags = h->flags & P_TYPE;

	/*
	 * If we're splitting the last page on a level because we're appending
	 * a key to it (skip is NEXTINDEX()), it's likely that the data is
	 * sorted.  Adding an empty page on the side of the level is less work
	 * and can push the fill factor much higher than normal.  If we're
	 * wrong it's no big deal, we'll just do the split the right way next
	 * time.  It may look like it's equally easy to do a similar hack for
	 * reverse sorted data, that is, split the tree left, but it's not.
	 * Don't even try.
	 */
	if (h->nextpg == P_INVALID && *skip == NEXTINDEX(h)) {
#ifdef STATISTICS
		++bt_sortsplit;
#endif
		h->nextpg = r->pgno;
		r->lower = BTDATAOFF + sizeof(indx_t);
		*skip = 0;
		*lp = h;
		*rp = r;
		return (r);
	}

	/* Put the new left page for the split into place. */
	if ((l = (PAGE *)calloc(1, t->bt_psize)) == NULL) {
		mpool_put(t->bt_mp, r, 0);
		return (NULL);
	}
	l->pgno = h->pgno;
	l->nextpg = r->pgno;
	l->prevpg = h->prevpg;
	l->lower = BTDATAOFF;
	l->upper = t->bt_psize;
	l->flags = h->flags & P_TYPE;

	/* Fix up the previous pointer of the page after the split page. */
	if (h->nextpg != P_INVALID) {
		if ((tp = mpool_get(t->bt_mp, h->nextpg, 0)) == NULL) {
			free(l);
			/* XXX mpool_free(t->bt_mp, r->pgno); */
			return (NULL);
		}
		tp->prevpg = r->pgno;
		mpool_put(t->bt_mp, tp, MPOOL_DIRTY);
	}

	/*
	 * Split right.  The key/data pairs aren't sorted in the btree page so
	 * it's simpler to copy the data from the split page onto two new pages
	 * instead of copying half the data to the right page and compacting
	 * the left page in place.  Since the left page can't change, we have
	 * to swap the original and the allocated left page after the split.
	 */
	tp = bt_psplit(t, h, l, r, skip, ilen);

	/* Move the new left page onto the old left page. */
	memmove(h, l, t->bt_psize);
	if (tp == l)
		tp = h;
	free(l);

	*lp = h;
	*rp = r;
	return (tp);
}
示例#14
0
文件: bt_seq.c 项目: 3bu1/crossbridge
/*
 * __bt_first --
 *	Find the first entry.
 *
 * Parameters:
 *	t:	the tree
 *    key:	the key
 *  erval:	return EPG
 * exactp:	pointer to exact match flag
 *
 * Returns:
 *	The first entry in the tree greater than or equal to key,
 *	or RET_SPECIAL if no such key exists.
 */
static int
__bt_first(BTREE *t, const DBT *key, EPG *erval, int *exactp)
{
	PAGE *h;
	EPG *ep, save;
	pgno_t pg;

	/*
	 * Find any matching record; __bt_search pins the page.
	 *
	 * If it's an exact match and duplicates are possible, walk backwards
	 * in the tree until we find the first one.  Otherwise, make sure it's
	 * a valid key (__bt_search may return an index just past the end of a
	 * page) and return it.
	 */
	if ((ep = __bt_search(t, key, exactp)) == NULL)
		return (0);
	if (*exactp) {
		if (F_ISSET(t, B_NODUPS)) {
			*erval = *ep;
			return (RET_SUCCESS);
		}

		/*
		 * Walk backwards, as long as the entry matches and there are
		 * keys left in the tree.  Save a copy of each match in case
		 * we go too far.
		 */
		save = *ep;
		h = ep->page;
		do {
			if (save.page->pgno != ep->page->pgno) {
				mpool_put(t->bt_mp, save.page, 0);
				save = *ep;
			} else
				save.index = ep->index;

			/*
			 * Don't unpin the page the last (or original) match
			 * was on, but make sure it's unpinned if an error
			 * occurs.
			 */
			if (ep->index == 0) {
				if (h->prevpg == P_INVALID)
					break;
				if (h->pgno != save.page->pgno)
					mpool_put(t->bt_mp, h, 0);
				if ((h = mpool_get(t->bt_mp,
				    h->prevpg, 0)) == NULL) {
					if (h->pgno == save.page->pgno)
						mpool_put(t->bt_mp,
						    save.page, 0);
					return (RET_ERROR);
				}
				ep->page = h;
				ep->index = NEXTINDEX(h);
			}
			--ep->index;
		} while (__bt_cmp(t, key, ep) == 0);

		/*
		 * Reach here with the last page that was looked at pinned,
		 * which may or may not be the same as the last (or original)
		 * match page.  If it's not useful, release it.
		 */
		if (h->pgno != save.page->pgno)
			mpool_put(t->bt_mp, h, 0);

		*erval = save;
		return (RET_SUCCESS);
	}

	/* If at the end of a page, find the next entry. */
	if (ep->index == NEXTINDEX(ep->page)) {
		h = ep->page;
		pg = h->nextpg;
		mpool_put(t->bt_mp, h, 0);
		if (pg == P_INVALID)
			return (RET_SPECIAL);
		if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
			return (RET_ERROR);
		ep->index = 0;
		ep->page = h;
	}
	*erval = *ep;
	return (RET_SUCCESS);
}
示例#15
0
/*
 * __bt_stkacq --
 *	Acquire a stack so we can delete a cursor entry.
 *
 * Parameters:
 *	  t:	tree
 *	 hp:	pointer to current, pinned PAGE pointer
 *	  c:	pointer to the cursor
 *
 * Returns:
 *	0 on success, 1 on failure
 */
static int
__bt_stkacq(BTREE *t, PAGE **hp, CURSOR *c)
{
	BINTERNAL *bi;
	EPG *e;
	EPGNO *parent;
	PAGE *h;
	indx_t idx;
	pgno_t pgno;
	recno_t nextpg, prevpg;
	int exact, level;

	/*
	 * Find the first occurrence of the key in the tree.  Toss the
	 * currently locked page so we don't hit an already-locked page.
	 */
	h = *hp;
	mpool_put(t->bt_mp, h, 0);
	if ((e = __bt_search(t, &c->key, &exact)) == NULL)
		return (1);
	h = e->page;

	/* See if we got it in one shot. */
	if (h->pgno == c->pg.pgno)
		goto ret;

	/*
	 * Move right, looking for the page.  At each move we have to move
	 * up the stack until we don't have to move to the next page.  If
	 * we have to change pages at an internal level, we have to fix the
	 * stack back up.
	 */
	while (h->pgno != c->pg.pgno) {
		if ((nextpg = h->nextpg) == P_INVALID)
			break;
		mpool_put(t->bt_mp, h, 0);

		/* Move up the stack. */
		for (level = 0; (parent = BT_POP(t)) != NULL; ++level) {
			/* Get the parent page. */
			if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
				return (1);

			/* Move to the next index. */
			if (parent->index != NEXTINDEX(h) - 1) {
				idx = parent->index + 1;
				BT_PUSH(t, h->pgno, idx);
				break;
			}
			mpool_put(t->bt_mp, h, 0);
		}

		/* Restore the stack. */
		while (level--) {
			/* Push the next level down onto the stack. */
			bi = GETBINTERNAL(h, idx);
			pgno = bi->pgno;
			BT_PUSH(t, pgno, 0);

			/* Lose the currently pinned page. */
			mpool_put(t->bt_mp, h, 0);

			/* Get the next level down. */
			if ((h = mpool_get(t->bt_mp, pgno, 0)) == NULL)
				return (1);
			idx = 0;
		}
		mpool_put(t->bt_mp, h, 0);
		if ((h = mpool_get(t->bt_mp, nextpg, 0)) == NULL)
			return (1);
	}

	if (h->pgno == c->pg.pgno)
		goto ret;

	/* Reacquire the original stack. */
	mpool_put(t->bt_mp, h, 0);
	if ((e = __bt_search(t, &c->key, &exact)) == NULL)
		return (1);
	h = e->page;

	/*
	 * Move left, looking for the page.  At each move we have to move
	 * up the stack until we don't have to change pages to move to the
	 * next page.  If we have to change pages at an internal level, we
	 * have to fix the stack back up.
	 */
	while (h->pgno != c->pg.pgno) {
		if ((prevpg = h->prevpg) == P_INVALID)
			break;
		mpool_put(t->bt_mp, h, 0);

		/* Move up the stack. */
		for (level = 0; (parent = BT_POP(t)) != NULL; ++level) {
			/* Get the parent page. */
			if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
				return (1);

			/* Move to the next index. */
			if (parent->index != 0) {
				idx = parent->index - 1;
				BT_PUSH(t, h->pgno, idx);
				break;
			}
			mpool_put(t->bt_mp, h, 0);
		}

		/* Restore the stack. */
		while (level--) {
			/* Push the next level down onto the stack. */
			bi = GETBINTERNAL(h, idx);
			pgno = bi->pgno;

			/* Lose the currently pinned page. */
			mpool_put(t->bt_mp, h, 0);

			/* Get the next level down. */
			if ((h = mpool_get(t->bt_mp, pgno, 0)) == NULL)
				return (1);

			idx = NEXTINDEX(h) - 1;
			BT_PUSH(t, pgno, idx);
		}
		mpool_put(t->bt_mp, h, 0);
		if ((h = mpool_get(t->bt_mp, prevpg, 0)) == NULL)
			return (1);
	}


ret:	mpool_put(t->bt_mp, h, 0);
	return ((*hp = mpool_get(t->bt_mp, c->pg.pgno, 0)) == NULL);
}
示例#16
0
文件: rec_seq.c 项目: aharri/obase
/*
 * __REC_SEQ -- Recno sequential scan interface.
 *
 * Parameters:
 *	dbp:	pointer to access method
 *	key:	key for positioning and return value
 *	data:	data return value
 *	flags:	R_CURSOR, R_FIRST, R_LAST, R_NEXT, R_PREV.
 *
 * Returns:
 *	RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key.
 */
int
__rec_seq(const DB *dbp, DBT *key, DBT *data, u_int flags)
{
	BTREE *t;
	EPG *e;
	recno_t nrec;
	int status;

	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 ((nrec = *(recno_t *)key->data) == 0)
			goto einval;
		break;
	case R_NEXT:
		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
			nrec = t->bt_cursor.rcursor + 1;
			break;
		}
		/* FALLTHROUGH */
	case R_FIRST:
		nrec = 1;
		break;
	case R_PREV:
		if (F_ISSET(&t->bt_cursor, CURS_INIT)) {
			if ((nrec = t->bt_cursor.rcursor - 1) == 0)
				return (RET_SPECIAL);
			break;
		}
		/* FALLTHROUGH */
	case R_LAST:
		if (!F_ISSET(t, R_EOF | R_INMEM) &&
		    t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
			return (RET_ERROR);
		nrec = t->bt_nrecs;
		break;
	default:
einval:		errno = EINVAL;
		return (RET_ERROR);
	}
	
	if (t->bt_nrecs == 0 || nrec > t->bt_nrecs) {
		if (!F_ISSET(t, R_EOF | R_INMEM) &&
		    (status = t->bt_irec(t, nrec)) != RET_SUCCESS)
			return (status);
		if (t->bt_nrecs == 0 || nrec > t->bt_nrecs)
			return (RET_SPECIAL);
	}

	if ((e = __rec_search(t, nrec - 1, SEARCH)) == NULL)
		return (RET_ERROR);

	F_SET(&t->bt_cursor, CURS_INIT);
	t->bt_cursor.rcursor = nrec;

	status = __rec_ret(t, e, nrec, key, data);
	if (F_ISSET(t, B_DB_LOCK))
		mpool_put(t->bt_mp, e->page, 0);
	else
		t->bt_pinned = e->page;
	return (status);
}
示例#17
0
/*
 * __bt_bdelete --
 *	Delete all key/data pairs matching the specified key.
 *
 * Parameters:
 *	  t:	tree
 *	key:	key to delete
 *
 * Returns:
 *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
 */
static int
__bt_bdelete(BTREE *t, const DBT *key)
{
	EPG *e;
	PAGE *h;
	int deleted, exact, redo;

	deleted = 0;

	/* Find any matching record; __bt_search pins the page. */
loop:	if ((e = __bt_search(t, key, &exact)) == NULL)
		return (deleted ? RET_SUCCESS : RET_ERROR);
	if (!exact) {
		mpool_put(t->bt_mp, e->page, 0);
		return (deleted ? RET_SUCCESS : RET_SPECIAL);
	}

	/*
	 * Delete forward, then delete backward, from the found key.  If
	 * there are duplicates and we reach either side of the page, do
	 * the key search again, so that we get them all.
	 */
	redo = 0;
	h = e->page;
	do {
		if (__bt_dleaf(t, key, h, e->index)) {
			mpool_put(t->bt_mp, h, 0);
			return (RET_ERROR);
		}
		if (F_ISSET(t, B_NODUPS)) {
			if (NEXTINDEX(h) == 0) {
				if (__bt_pdelete(t, h))
					return (RET_ERROR);
			} else
				mpool_put(t->bt_mp, h, MPOOL_DIRTY);
			return (RET_SUCCESS);
		}
		deleted = 1;
	} while (e->index < NEXTINDEX(h) && __bt_cmp(t, key, e) == 0);

	/* Check for right-hand edge of the page. */
	if (e->index == NEXTINDEX(h))
		redo = 1;

	/* Delete from the key to the beginning of the page. */
	while (e->index-- > 0) {
		if (__bt_cmp(t, key, e) != 0)
			break;
		if (__bt_dleaf(t, key, h, e->index) == RET_ERROR) {
			mpool_put(t->bt_mp, h, 0);
			return (RET_ERROR);
		}
		if (e->index == 0)
			redo = 1;
	}

	/* Check for an empty page. */
	if (NEXTINDEX(h) == 0) {
		if (__bt_pdelete(t, h))
			return (RET_ERROR);
		goto loop;
	}

	/* Put the page. */
	mpool_put(t->bt_mp, h, MPOOL_DIRTY);

	if (redo)
		goto loop;
	return (RET_SUCCESS);
}
示例#18
0
/*
 * __bt_seqadvance --
 *	Advance the sequential scan.
 *
 * Parameters:
 *	t:	tree
 *	flags:	R_NEXT, R_PREV
 *
 * Side effects:
 *	Pins the page the new key/data record is on.
 *
 * Returns:
 *	RET_ERROR, RET_SUCCESS or RET_SPECIAL if there's no next key.
 */
static int
__bt_seqadv(BTREE *t, EPG *ep, int flags)
{
	CURSOR *c;
	PAGE *h;
	indx_t idx;
	pgno_t pg;
	int exact;

	/*
	 * There are a couple of states that we can be in.  The cursor has
	 * been initialized by the time we get here, but that's all we know.
	 */
	c = &t->bt_cursor;

	/*
	 * The cursor was deleted where there weren't any duplicate records,
	 * so the key was saved.  Find out where that key would go in the
	 * current tree.  It doesn't matter if the returned key is an exact
	 * match or not -- if it's an exact match, the record was added after
	 * the delete so we can just return it.  If not, as long as there's
	 * a record there, return it.
	 */
	if (F_ISSET(c, CURS_ACQUIRE))
		return (__bt_first(t, &c->key, ep, &exact));

	/* Get the page referenced by the cursor. */
	if ((h = mpool_get(t->bt_mp, c->pg.pgno, 0)) == NULL)
		return (RET_ERROR);

	/*
	 * Find the next/previous record in the tree and point the cursor at
	 * it.  The cursor may not be moved until a new key has been found.
	 */
	switch (flags) {
	case R_NEXT:			/* Next record. */
		/*
		 * The cursor was deleted in duplicate records, and moved
		 * forward to a record that has yet to be returned.  Clear
		 * that flag, and return the record.
		 */
		if (F_ISSET(c, CURS_AFTER))
			goto usecurrent;
		idx = c->pg.index;
		if (++idx == NEXTINDEX(h)) {
			pg = h->nextpg;
			mpool_put(t->bt_mp, h, 0);
			if (pg == P_INVALID)
				return (RET_SPECIAL);
			if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
				return (RET_ERROR);
			idx = 0;
		}
		break;
	case R_PREV:			/* Previous record. */
		/*
		 * The cursor was deleted in duplicate records, and moved
		 * backward to a record that has yet to be returned.  Clear
		 * that flag, and return the record.
		 */
		if (F_ISSET(c, CURS_BEFORE)) {
usecurrent:		F_CLR(c, CURS_AFTER | CURS_BEFORE);
			ep->page = h;
			ep->index = c->pg.index;
			return (RET_SUCCESS);
		}
		idx = c->pg.index;
		if (idx == 0) {
			pg = h->prevpg;
			mpool_put(t->bt_mp, h, 0);
			if (pg == P_INVALID)
				return (RET_SPECIAL);
			if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
				return (RET_ERROR);
			idx = NEXTINDEX(h) - 1;
		} else
			--idx;
		break;
	}

	ep->page = h;
	ep->index = idx;
	return (RET_SUCCESS);
}
示例#19
0
/*
 * BT_STAT -- Gather/print the tree statistics
 *
 * Parameters:
 *	dbp:	pointer to the DB
 */
void
__bt_stat(DB *dbp)
{
	extern unsigned long bt_cache_hit, bt_cache_miss, bt_pfxsaved, bt_rootsplit;
	extern unsigned long bt_sortsplit, bt_split;
	BTREE *t;
	PAGE *h;
	pgno_t i, pcont, pinternal, pleaf;
	unsigned long ifree, lfree, nkeys;
	int levels;

	t = dbp->internal;
	pcont = pinternal = pleaf = 0;
	nkeys = ifree = lfree = 0;
	for (i = P_ROOT; (h = mpool_get(t->bt_mp, i, 0)) != NULL; ++i) {
		switch (h->flags & P_TYPE) {
		case P_BINTERNAL:
		case P_RINTERNAL:
			++pinternal;
			ifree += h->upper - h->lower;
			break;
		case P_BLEAF:
		case P_RLEAF:
			++pleaf;
			lfree += h->upper - h->lower;
			nkeys += NEXTINDEX(h);
			break;
		case P_OVERFLOW:
			++pcont;
			break;
		}
		(void)mpool_put(t->bt_mp, h, 0);
	}

	/* Count the levels of the tree. */
	for (i = P_ROOT, levels = 0 ;; ++levels) {
		h = mpool_get(t->bt_mp, i, 0);
		if (h->flags & (P_BLEAF|P_RLEAF)) {
			if (levels == 0)
				levels = 1;
			(void)mpool_put(t->bt_mp, h, 0);
			break;
		}
		i = F_ISSET(t, R_RECNO) ?
		    GETRINTERNAL(h, 0)->pgno :
		    GETBINTERNAL(h, 0)->pgno;
		(void)mpool_put(t->bt_mp, h, 0);
	}

	(void)fprintf(stderr, "%d level%s with %ld keys",
	    levels, levels == 1 ? "" : "s", nkeys);
	if (F_ISSET(t, R_RECNO))
		(void)fprintf(stderr, " (%ld header count)", (long)t->bt_nrecs);
	(void)fprintf(stderr,
	    "\n%lu pages (leaf %ld, internal %ld, overflow %ld)\n",
	    (long)pinternal + pleaf + pcont, (long)pleaf, (long)pinternal,
	    (long)pcont);
	(void)fprintf(stderr, "%ld cache hits, %ld cache misses\n",
	    bt_cache_hit, bt_cache_miss);
	(void)fprintf(stderr, "%ld splits (%ld root splits, %ld sort splits)\n",
	    bt_split, bt_rootsplit, bt_sortsplit);
	pleaf *= t->bt_psize - BTDATAOFF;
	if (pleaf)
		(void)fprintf(stderr,
		    "%.0f%% leaf fill (%ld bytes used, %ld bytes free)\n",
		    ((double)(pleaf - lfree) / pleaf) * 100,
		    pleaf - lfree, lfree);
	pinternal *= t->bt_psize - BTDATAOFF;
	if (pinternal)
		(void)fprintf(stderr,
		    "%.0f%% internal fill (%ld bytes used, %ld bytes free\n",
		    ((double)(pinternal - ifree) / pinternal) * 100,
		    pinternal - ifree, ifree);
	if (bt_pfxsaved)
		(void)fprintf(stderr, "prefix checking removed %lu bytes.\n",
		    bt_pfxsaved);
}