db4.8_dump - Write database to flat-text format
db4.8_dump [-klNpRrV] [-d ahr] [-f output] [-h home] [-P password] [-s
The db4.8_dump utility reads the database file file and writes it to
the standard output using a portable flat-text format understood by the
db4.8_load utility. The file argument must be a file produced using
the Berkeley DB library functions.
-d Dump the specified database in a format helpful for debugging
the Berkeley DB library routines.
a Display all information.
h Display only page headers.
r Do not display the free-list or pages on the free list.
This mode is used by the recovery tests.
The output format of the -d option is not standard and may
change, without notice, between releases of the Berkeley DB
-f Write to the specified file instead of to the standard output.
-h Specify a home directory for the database environment; by
default, the current working directory is used.
-k Dump record numbers from Queue and Recno databases as keys.
-l List the databases stored in the file.
-N Do not acquire shared region mutexes while running. Other
problems, such as potentially fatal errors in Berkeley DB, will
be ignored as well. This option is intended only for debugging
errors, and should not be used under any other circumstances.
-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
-p If characters in either the key or data items are printing
characters (as defined by isprint(3)), use printing characters
in file to represent them. This option permits users to use
standard text editors and tools to modify the contents of
Note: different systems may have different notions about what
characters are considered printing characters, and databases
dumped in this manner may be less portable to external systems.
-R Aggressively salvage data from a possibly corrupt file. The -R
flag differs from the -r option in that it will return all
possible data from the file at the risk of also returning
already deleted or otherwise nonsensical items. Data dumped in
this fashion will almost certainly have to be edited by hand or
other means before the data is ready for reload into another
-r Salvage data from a possibly corrupt file. When used on a
uncorrupted database, this option should return equivalent data
to a normal dump, but most likely in a different order.
-s Specify a single database to dump. If no database is specified,
all databases in the database file are dumped.
-V Write the library version number to the standard output, and
Dumping and reloading Hash databases that use user-defined hash
functions will result in new databases that use the default hash
function. Although using the default hash function may not be optimal
for the new database, it will continue to work correctly.
Dumping and reloading Btree databases that use user-defined prefix or
comparison functions will result in new databases that use the default
prefix and comparison functions. In this case, it is quite likely that
the database will be damaged beyond repair permitting neither record
storage or retrieval.
The only available workaround for either case is to modify the sources
for the db4.8_load utility to load the database using the correct hash,
prefix, and comparison functions.
The db4.8_dump utility output format is documented in the Dump Output
Formats section of the Berkeley DB Reference Guide.
The db4.8_dump 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_dump should always be given the chance
to detach from the environment and exit gracefully. To cause
db4.8_dump to release all environment resources and exit cleanly, send
it an interrupt signal (SIGINT).
Even when using a Berkeley DB database environment, the db4.8_dump
utility does not use any kind of database locking if it is invoked with
the -d, -R, or -r arguments. If used with one of these arguments, the
db4.8_dump utility may only be safely run on databases that are not
being modified by any other process; otherwise, the output may be
The db4.8_dump utility exits 0 on success, and >0 if an error occurs.
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.
Sleepycat Software, Inc. This manual page was created based on the HTML
documentation for db_dump from Sleepycat, by Thijs Kinkhorst
<email@example.com>, for the Debian system (but may be used by
28 January 2005