Section: BerkeleyDB Utilities (1)
Updated: 06 December 2016
db_dump - Write database file using flat-text format
[-klNpRrV] [-b blob-dir
] [-d ahr]
] [-h home
] [-P password
] [-s database
] [-D bytes
[-kNpV] [-d ahr] [-f output] [-h home] -m database
[-p] [-f output] file
utility reads the database file
and writes it to the standard
output using a portable flat-text format understood by the db_load
argument must be a file produced using the Berkeley DB library
utility is similar to the db_dump utility, except that it reads
databases in the format used by Berkeley DB versions 1.85 and 1.86.
- -b blob-dir
Specifies the directory where BLOB data is stored for the database you are dumping.
Dump the specified database in a format helpful for debugging the Berkeley DB
Display all information.
Display only page headers.
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 library.
- -D bytes
Specifies the maximum number of bytes to dump for each key/data item found in the specified database.
This option is only valid when -da is also specified. This option overrides the value set for
the "set_data_len" parameter in your DB_CONFIG file, if any.
- -f output
Write to the specified output file instead of to the standard output.
- -h home
Specify a home directory for the database environment; by
default, the current working directory is used.
Dump record numbers from Queue and Recno databases as keys.
List the databases stored in the file.
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 password
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.
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 databases.
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.
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 database
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 database
Specify a single database to dump. If no database is specified, all
databases in the database file are dumped.
Write the library version number to the standard output, and exit.
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 db_load utility to load the database using the correct
hash, prefix, and comparison functions.
The db_dump utility output format is documented in the
Dump Output Formats section of the Berkeley DB Reference Guide.
The db_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, db_dump should always be given the chance to
detach from the environment and exit gracefully. To cause db_dump
to release all environment resources and exit cleanly, send it an
interrupt signal (SIGINT).
Even when using a Berkeley DB database environment, the db_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 db_dump utility may only be safely
run on databases that are not being modified by any other process;
otherwise, the output may be corrupt.
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