Library Version 12.1.6.0

Db::sync()
Prev | Chapter 2. The Db Handle | Next

## Db::sync()

    #include <db_cxx.h>

    int
    Db::sync(u_int32_t flags);

The `Db::sync()` method flushes any cached information to disk. This method operates on the database file level, so if the file contains multiple database handles then this method will flush to disk any information that is cached for any of those handles.

If the database is in memory only, the `Db::sync()` method has no effect and will always succeed.

It is important to understand that flushing cached information to disk only minimizes the window of opportunity for corrupted data. Although unlikely, it is possible for database corruption to happen if a system or application crash occurs while writing data to the database. To ensure that database corruption never occurs, applications must either: use transactions and logging with automatic recovery; use logging and application-specific recovery; or edit a copy of the database, and once all applications using the database have successfully called Db::close(), atomically replace the original database with the updated copy.

The `Db::sync()` 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

#### flags

The flags parameter is currently unused, and must be set to 0.

### Errors

The `Db::sync()` 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:

#### DbRepHandleDeadException or DB_REP_HANDLE_DEAD

When a client synchronizes with the master, it is possible for committed transactions to be rolled back. This invalidates all the database and cursor handles opened in the replication environment. Once this occurs, an attempt to use such a handle will throw a DbRepHandleDeadException (if your application is configured to throw exceptions), or return `DB_REP_HANDLE_DEAD`. The application will need to discard the handle and open a new one in order to continue processing.

#### DbDeadlockException or DB_REP_LOCKOUT

The operation was blocked by client/master synchronization.

DbDeadlockException is thrown if your Berkeley DB API is configured to throw exceptions. Otherwise, `DB_REP_LOCKOUT` is returned.

#### EINVAL

An invalid flag value or parameter was specified.

### Class

Db

### See Also

Database and Related Methods

Prev | Up | Next
Db::stat_print() | Home | Db::truncate()