db_dump(1) BSD General Commands Manual db_dump(1)NAMEdb_dumpSYNOPSISdb_dump [-klNpRrV] [-d ahr] [-f output] [-h home] [-P password]
[-s database] file
DESCRIPTION
The db_dump utility reads the database file file and writes it to the
standard output using a portable flat-text format understood by the
db_load utility. The file argument must be a file produced using the
Berkeley DB library functions.
The options are as follows:
-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 library.
-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 over‐
write 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.
-p
If characters in either the key or data items are printing characters
(as defined by isprint(3)), use printing characters in file to repre‐
sent 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 charac‐
ters 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 other‐
wise nonsensical items. Data dumped in this fashion will almost cer‐
tainly have to be edited by hand or other means before the data is
ready for reload into another database
-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 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, pre‐
fix, and comparison functions.
The db_dump utility output format is documented in the Dump Output For‐
mats 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 envi‐
ronment, db_dump should always be given the chance to detach from the
environment and exit gracefully. To cause db_dump to release all environ‐
ment 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.
The db_dump utility exits 0 on success, and >0 if an error occurs.
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.
SEE ALSOdb_archive(1), db_checkpoint(1), db_deadlock(1), db_load(1),
db_printlog(1), db_recover(1), db_stat(1), db_upgrade(1), db_verify(1)Darwin December 3, 2003 Darwin
