MDB_DUMP(1):

MDB_DUMP(1)		MDB_DUMP(1)
LMDB 1.0.0	2026/04/28	MDB_DUMP(1)
NAME mdb_dump − LMDB environment export tool SYNOPSIS mdb_dump [−V] [−f file] [−i txnid] [−l] [−n] [−v] [−L] [−p] [−m module [−w password]] [−a \| −s subdb] envpath DESCRIPTION The mdb_dump utility reads a database and writes its contents to the standard output using a portable flat-text format understood by the mdb_load(1) utility. OPTIONS −V Write the library version number to the standard output, and exit. −f file Write to the specified file instead of to the standard output. −i txnid Perform an incremental backup. Only pages that have been modified after the given transaction ID will be written in the dump. Note: This is a raw binary dump of the database pages, not the portable output format. −l List the databases stored in the environment. Just the names will be listed, no data will be output. −n Dump an LMDB environment which does not use subdirectories. −v Use the previous environment state instead of the latest state. This may be useful if the latest state has been corrupted. −L Access the LMDB environment without any locking. If concurrent access is anticipated, the caller must manage all concurrency itself. −p If characters in either the key or data items are printing characters (as defined by isprint(3)), output them directly. 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. −m module Load the specified dynamic module to utilize cryptographic functions. This is required to operate on environments that have been configured with page-level checksums or encryption. −w password Specify the password for an encrypted environment. This is only used if a cryptography module has been loaded. −a Dump all of the subdatabases in the environment. −s subdb Dump a specific subdatabase. If no database is specified, only the main database is dumped. DIAGNOSTICS Exit status is zero if no errors occur. Errors result in a non-zero exit status and a diagnostic message being written to standard error. Dumping databases that use user-defined comparison functions will output records with the ordering imposed by those comparison functions. If mdb_load is invoked without including the -a option when reloading those records, the new databases will likely be damaged beyond repair, permitting neither record storage nor retrieval. SEE ALSO mdb_load(1) AUTHOR Howard Chu of Symas Corporation <http://www.symas.com>

MDB_DUMP(1)

LMDB 1.0.0

2026/04/28

MDB_DUMP(1)

NAME

mdb_dump − LMDB environment export tool

SYNOPSIS

mdb_dump

−V

−f

file

−i

txnid

−l

−n

−v

−L

−p

−m

module

−w

password

−a

−s

subdb

envpath

DESCRIPTION

mdb_dump

mdb_load

OPTIONS

−V: Write the library version number to the standard output, and exit.

−f file: Write to the specified file instead of to the standard output.

−i txnid: Perform an incremental backup. Only pages that have been modified after the given transaction ID will be written in the dump.
Note: This is a raw binary dump of the database pages, not the portable output format.

−l: List the databases stored in the environment. Just the names will be listed, no data will be output.

−n: Dump an LMDB environment which does not use subdirectories.

−v: Use the previous environment state instead of the latest state. This may be useful if the latest state has been corrupted.

−L: Access the LMDB environment without any locking. If concurrent access is anticipated, the caller must manage all concurrency itself.

−p: If characters in either the key or data items are printing characters (as defined by isprint(3)), output them directly. 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.

−m module: Load the specified dynamic module to utilize cryptographic functions. This is required to operate on environments that have been configured with page-level checksums or encryption.

−w password: Specify the password for an encrypted environment. This is only used if a cryptography module has been loaded.

−a: Dump all of the subdatabases in the environment.

−s subdb: Dump a specific subdatabase. If no database is specified, only the main database is dumped.

DIAGNOSTICS

Dumping databases that use user-defined comparison functions will output records with the ordering imposed by those comparison functions. If mdb_load is invoked without including the -a option when reloading those records, the new databases will likely be damaged beyond repair, permitting neither record storage nor retrieval.

AUTHOR