| btree.3 (84306) | btree.3 (108087) |
|---|---|
| 1.\" Copyright (c) 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 16 unchanged lines hidden (view full) --- 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)btree.3 8.4 (Berkeley) 8/18/94 | 1.\" Copyright (c) 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 16 unchanged lines hidden (view full) --- 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)btree.3 8.4 (Berkeley) 8/18/94 |
| 33.\" $FreeBSD: head/lib/libc/db/man/btree.3 84306 2001-10-01 16:09:29Z ru $ | 33.\" $FreeBSD: head/lib/libc/db/man/btree.3 108087 2002-12-19 09:40:28Z ru $ |
| 34.\" 35.Dd August 18, 1994 36.Dt BTREE 3 37.Os 38.Sh NAME 39.Nm btree 40.Nd "btree database access method" 41.Sh SYNOPSIS --- 125 unchanged lines hidden (view full) --- 167is opened. 168If 169.Va compare 170is 171.Dv NULL 172(no comparison function is specified), the keys are compared 173lexically, with shorter keys considered less than longer keys. 174.It Va prefix | 34.\" 35.Dd August 18, 1994 36.Dt BTREE 3 37.Os 38.Sh NAME 39.Nm btree 40.Nd "btree database access method" 41.Sh SYNOPSIS --- 125 unchanged lines hidden (view full) --- 167is opened. 168If 169.Va compare 170is 171.Dv NULL 172(no comparison function is specified), the keys are compared 173lexically, with shorter keys considered less than longer keys. 174.It Va prefix |
| 175.Va Prefix | 175The 176.Va prefix 177element |
| 176is the prefix comparison function. 177If specified, this routine must return the number of bytes of the second key 178argument which are necessary to determine that it is greater than the first 179key argument. 180If the keys are equal, the key length should be returned. 181Note, the usefulness of this routine is very data dependent, but, in some 182data sets can produce significantly reduced tree sizes and search times. 183If --- 17 unchanged lines hidden (view full) --- 201If 202.Va lorder 203is 0 (no order is specified) the current host order is used. 204.El 205.Pp 206If the file already exists (and the 207.Dv O_TRUNC 208flag is not specified), the | 178is the prefix comparison function. 179If specified, this routine must return the number of bytes of the second key 180argument which are necessary to determine that it is greater than the first 181key argument. 182If the keys are equal, the key length should be returned. 183Note, the usefulness of this routine is very data dependent, but, in some 184data sets can produce significantly reduced tree sizes and search times. 185If --- 17 unchanged lines hidden (view full) --- 203If 204.Va lorder 205is 0 (no order is specified) the current host order is used. 206.El 207.Pp 208If the file already exists (and the 209.Dv O_TRUNC 210flag is not specified), the |
| 209values specified for the parameters | 211values specified for the |
| 210.Va flags , lorder 211and 212.Va psize | 212.Va flags , lorder 213and 214.Va psize |
| 215arguments |
|
| 213are ignored 214in favor of the values used when the tree was created. 215.Pp 216Forward sequential scans of a tree are from the least key to the greatest. 217.Pp 218Space freed up by deleting key/data pairs from the tree is never reclaimed, 219although it is normally made available for reuse. 220This means that the --- 52 unchanged lines hidden --- | 216are ignored 217in favor of the values used when the tree was created. 218.Pp 219Forward sequential scans of a tree are from the least key to the greatest. 220.Pp 221Space freed up by deleting key/data pairs from the tree is never reclaimed, 222although it is normally made available for reuse. 223This means that the --- 52 unchanged lines hidden --- |