NAME
db4.8_load - Load data from standard input
SYNOPSIS
db4.8_load [-nTV] [-c name=value] [-f file] [-h home] [-P password] [-t
btree | hash | queue | recno] file
db4.8_load [-r lsn | fileid] [-h home] [-P password] file
DESCRIPTION
The db4.8_load utility reads from the standard input and loads it into
the database file. The database file is created if it does not already
exist.
The input to db4.8_load must be in the output format specified by the
db4.8_dump utility, utilities, or as specified for the -T below.
OPTIONS
-c Specify configuration options ignoring any value they may have
based on the input. The command-line format is name=value. See
the Supported Keywords section below for a list of keywords
supported by the -c option.
-f Read from the specified input file instead of from the standard
input.
-h Specify a home directory for the database environment.
If a home directory is specified, the database environment is
opened using the DB_INIT_LOCK, DB_INIT_LOG, DB_INIT_MPOOL,
DB_INIT_TXN, and DB_USE_ENVIRON flags to DB_ENV->open. (This
means that db4.8_load can be used to load data into databases
while they are in use by other processes.) If the DB_ENV->open
call fails, or if no home directory is specified, the database
is still updated, but the environment is ignored; for example,
no locking is done.
-n Do not overwrite existing keys in the database when loading into
an already existing database. If a key/data pair cannot be
loaded into the database for this reason, a warning message is
displayed on the standard error output, and the key/data pair
are skipped.
-P Specify an environment password. Although Berkeley DB utilities
overwrite password strings as soon as possible, be aware there
may be a window of vulnerability on systems where unprivileged
users can see command-line arguments or where utilities are not
able to overwrite the memory containing the command-line
arguments.
-r Reset the database’s file ID or log sequence numbers (LSNs).
All database pages in transactional environments contain
references to the environment’s log records. In order to copy a
database into a different database environment, database page
references to the old environment’s log records must be reset,
otherwise data corruption can occur when the database is
modified in the new environment. The -r lsn option resets a
database’s log sequence numbers.
All databases contain an ID string used to identify the database
in the database environment cache. If a database is copied, and
used in the same environment as another file with the same ID
string, corruption can occur. The -r fileid option resets a
database’s file ID to a new value.
In both cases, the physical file specified by the file argument
is modified in-place.
-T The -T option allows non-Berkeley DB applications to easily load
text files into databases.
If the database to be created is of type Btree or Hash, or the
keyword keys is specified as set, the input must be paired lines
of text, where the first line of the pair is the key item, and
the second line of the pair is its corresponding data item. If
the database to be created is of type Queue or Recno and the
keyword keys is not set, the input must be lines of text, where
each line is a new data item for the database.
A simple escape mechanism, where newline and backslash (\)
characters are special, is applied to the text input. Newline
characters are interpreted as record separators. Backslash
characters in the text will be interpreted in one of two ways:
If the backslash character precedes another backslash character,
the pair will be interpreted as a literal backslash. If the
backslash character precedes any other character, the two
characters following the backslash will be interpreted as a
hexadecimal specification of a single character; for example,
\0a is a newline character in the ASCII character set.
For this reason, any backslash or newline characters that
naturally occur in the text input must be escaped to avoid
misinterpretation by db4.8_load.
If the -T option is specified, the underlying access method type
must be specified using the -t option.
-t Specify the underlying access method. If no -t option is
specified, the database will be loaded into a database of the
same type as was dumped; for example, a Hash database will be
created if a Hash database was dumped.
Btree and Hash databases may be converted from one to the other.
Queue and Recno databases may be converted from one to the
other. If the -k option was specified on the call to db4.8_dump
then Queue and Recno databases may be converted to Btree or
Hash, with the key being the integer record number.
-V Write the library version number to the standard output, and
exit.
The db4.8_load utility may be used with a Berkeley DB environment (as
described for the -h option, the environment variable DB_HOME, or
because the utility was run in a directory containing a Berkeley DB
environment). In order to avoid environment corruption when using a
Berkeley DB environment, db4.8_load should always be given the chance
to detach from the environment and exit gracefully. To cause
db4.8_load to release all environment resources and exit cleanly, send
it an interrupt signal (SIGINT).
The db4.8_load utility exits 0 on success, 1 if one or more key/data
pairs were not loaded into the database because the key already
existed, and >1 if an error occurs.
EXAMPLES
The db4.8_load utility can be used to load text files into databases.
For example, the following command loads the standard UNIX /etc/passwd
file into a database, with the login name as the key item and the
entire password entry as the data item:
awk -F: ’{print $1; print $0}’ < /etc/passwd | sed ’s/\\/\\\\/g’ |
db4.8_load -T -t hash passwd.db
Note that backslash characters naturally occurring in the text are
escaped to avoid interpretation as escape characters by db4.8_load.
ENVIRONMENT
DB_HOME
If the -h option is not specified and the environment variable
DB_HOME is set, it is used as the path of the database home, as
described in DB_ENV->open.
SUPPORTED KEYWORDS
The following keywords are supported for the -c command-line ption to
the db4.8_load utility. See DB->open for further discussion of these
keywords and what values should be specified.
The parenthetical listing specifies how the value part of the
name=value pair is interpreted. Items listed as (boolean) expect value
to be 1 (set) or 0 (unset). Items listed as (number) convert value to
a number. Items listed as (string) use the string value without
modification.
bt_minkey
The minimum number of keys per page.
chksum Enable page checksums.
database
The database to load.
db_lorder
The byte order for integers in the stored database metadata.
db_pagesize
The size of database pages, in bytes.
duplicates
The value of the DB_DUP flag.
dupsort
The value of the DB_DUPSORT flag.
extentsize
The size of database extents, in pages, for Queue databases
configured to use extents.
h_ffactor
The density within the Hash database.
h_nelem
The size of the Hash database.
keys Specify whether keys are present for Queue or Recno databases.
re_len Specify fixed-length records of the specified length.
re_pad Specify the fixed-length record pad character.
recnum The value of the DB_RECNUM flag.
renumber
The value of the DB_RENUMBER flag.
subdatabase
The subdatabase to load.
AUTHORS
Sleepycat Software, Inc. This manual page was created based on the HTML
documentation for db_load from Sleepycat, by Thijs Kinkhorst
<thijs@kinkhorst.com>, for the Debian system (but may be used by
others).
22 November 2009