MAN page from CentOS 8 libdb-utils-5.3.28-36.el8.i686.rpm


Section: BerkeleyDB Utilities (1)
Updated: 06 December 2016


db_dump - Write database file using flat-text format 


db_dump[-klNpRrV] [-b blob-dir] [-d ahr][-f output] [-h home] [-P password] [-s database] [-D bytes] file

db_dump[-kNpV] [-d ahr] [-f output] [-h home] -m database

db_dump185[-p] [-f output] file 


The db_dump utility reads the database file and writes it to the standardoutput using a portable flat-text format understood by the db_load utility.The file argument must be a file produced using the Berkeley DB libraryfunctions.The db_dump185 utility is similar to the db_dump utility, except that it readsdatabases 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 DBlibrary routines.
Display all information.
Display only page headers.
Do not display the free-list or pages on the free list. Thismode 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 forthe "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; bydefault, 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 beused under any other circumstances.
-P password
Specify an environment password. Although Berkeley DB utilities overwritepassword strings as soon as possible, be aware there may be a window ofvulnerability on systems where unprivileged users can see command-linearguments or where utilities are not able to overwrite the memorycontaining the command-line arguments.
If characters in either the key or data items are printing characters (asdefined by isprint(3)), use printing characters in fileto represent them. This option permits users to use standard text editorsand tools to modify the contents of databases.

Note: different systems may have different notions about what charactersare considered printing characters, and databases dumped inthis manner may be less portable to external systems.

Aggressively salvage data from a possibly corrupt file. The -Rflag differs from the -r option in that it will return allpossible data from the file at the risk of also returning already deletedor otherwise nonsensical items. Data dumped in this fashion will almostcertainly have to be edited by hand or other means before the data isready for reload into another database
Salvage data from a possibly corrupt file. When used on a uncorrupteddatabase, this option should return equivalent data to a normal dump, butmost likely in a different order.
-s database
Specify a single database to dump. If no database is specified, alldatabases 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 hashfunctions will result in new databases that use the default hashfunction. Although using the default hash function may not be optimalfor the new database, it will continue to work correctly.

Dumping and reloading Btree databases that use user-defined prefix orcomparison functions will result in new databases that use the defaultprefix and comparison functions.In this case, it is quite likely that the database will be damagedbeyond repair permitting neither record storage or retrieval.

The only available workaround for either case is to modify the sourcesfor the db_load utility to load the database using the correcthash, prefix, and comparison functions.

The db_dump utility output format is documented in theDump 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, orbecause the utility was run in a directory containing a Berkeley DBenvironment). In order to avoid environment corruption when using aBerkeley DB environment, db_dump should always be given the chance todetach from the environment and exit gracefully. To cause db_dumpto release all environment resources and exit cleanly, send it aninterrupt signal (SIGINT).

Even when using a Berkeley DB database environment, the db_dumputility does not use any kind of database locking if it is invoked withthe -d, -R, or -r arguments. If used withone of these arguments, the db_dump utility may only be safelyrun 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. 


If the -h option is not specified and the environment variableDB_HOME is set, it is used as the path of the database home, as describedin DB_ENV->open.






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