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DbEnv::lsn_reset()
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## DbEnv::lsn_reset()

    #include <db_cxx.h>

    int
    DbEnv::lsn_reset(const char *file, u_int32_t flags);

The `DbEnv::lsn_reset()` method allows database files to be moved from one transactional database environment to another.

Database pages in transactional database environments contain references to the environment's log files (that is, log sequence numbers, or LSNs). Copying or moving a database file from one database environment to another, and then modifying it, can result in data corruption if the LSNs are not first cleared.

Note that LSNs should be reset before moving or copying the database file into a new database environment, rather than moving or copying the database file and then resetting the LSNs. Berkeley DB has consistency checks that may be triggered if an application calls `DbEnv::lsn_reset()` on a database in a new environment when the database LSNs still reflect the old environment.

The `DbEnv::lsn_reset()` method modifies the physical file, in-place. Applications should not reset LSNs in files that are currently in use.

The `DbEnv::lsn_reset()` method is a non-atomic operation. If the operation fails, it is possible for the database to be in an inconsistent state.

The `DbEnv::lsn_reset()` method may be called at any time during the life of the application.

The `DbEnv::lsn_reset()` method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success.

### Parameters

#### file

The name of the physical file in which the LSNs are to be cleared.

#### flags

The flags parameter must be set to 0 or the following value:

- `DB_ENCRYPT`

  The file contains encrypted databases.

### Errors

The `DbEnv::lsn_reset()` method may fail and throw a DbException exception, encapsulating one of the following non-zero errors, or return one of the following non-zero errors:

#### EINVAL

An invalid flag value or parameter was specified.

### Class

DbEnv

### See Also

Database Environments and Related Methods

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