bt_recnum.so

berkeley db 4.6.21的源码。berkeley db是一个简单的数据库管理系统

m4_comment([$Id: bt_recnum.so,v 10.23 2002/06/24 14:50:23 bostic Exp $])

m4_ref_title(Access Methods,
    Retrieving Btree records by logical record number,
    [retrieving Btree records by logical record @number,
    retrieving Btree records by @logical record @number],
    am_conf/bt_minkey, am_conf/h_ffactor)

m4_p([dnl
The Btree access method optionally supports retrieval by logical record
numbers.  To configure a Btree to support record numbers, call the
m4_refT(dbh_set_flags) with the m4_ref(DB_RECNUM) flag.])

m4_p([dnl
Configuring a Btree for record numbers should not be done lightly.
While often useful, it may significantly slow down the speed at which
items can be stored into the database, and can severely impact
application throughput.  Generally it should be avoided in trees with
a need for high write concurrency.])

m4_p([dnl
To retrieve by record number, use the m4_ref(DB_SET_RECNO) flag to the
m4_ref(dbh_get) and m4_refT(dbc_get)s.  The following is an example of
a routine that displays the data item for a Btree database created with
the m4_ref(DB_RECNUM) option.])

include(ref/am_conf/bt_recnum1.cs)

m4_p([dnl
To determine a key's record number, use the m4_ref(DB_GET_RECNO) flag
to the m4_refT(dbc_get).  The following is an example of a routine that
displays the record number associated with a specific key.])

include(ref/am_conf/bt_recnum2.cs)

m4_page_footer