DB_DUMP(1) BerkeleyDB Utilities DB_DUMP(1)
NAME
db_dump - Write database file using flat-text format
SYNOPSIS
db_dump [-klNpRrV] [-d ahr] [-f output] [-h home] [-P password] [-s
database] file
db_dump [-kNpV] [-d ahr] [-f output] [-h home] -m database
db_dump185 [-p] [-f output] file
DESCRIPTION
The db_dump utility reads the database file and writes it to the stan-
dard 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 db_dump185 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.
OPTIONS
-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 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.
-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 prob-
lems, 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 argu-
ments.
-p If characters in either the key or data items are printing char-
acters (as defined by isprint(3)), use printing characters in
file to represent them. This option permits users to use stan-
dard 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.
-R Aggressively salvage data from a possibly corrupt file. The -R
flag differs from the -r option in that it will return all pos-
sible 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
-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 database
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 func-
tions 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 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 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 inter-
rupt 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.
EXIT STATUS
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 ALSO
db_archive(1) db_checkpoint(1) db_deadlock(1) db_hotbackup(1)
db_log_verify(1) db_load(1) db_printlog(1) db_recover(1) db_repli-
cate(1) db_stat(1) db_tuner(1) db_upgrade(1) db_verify(1)
BerkeleyDB 5.3.21 06 December 2016 DB_DUMP(1)
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