# Berkeley DB: DbEnv.set_lg_bsize
Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++

# DbEnv.set_lg_bsize

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    import com.sleepycat.db.*;

    public void set_lg_bsize(int lg_bsize)
        throws DbException;

# Description

Set the size of the in-memory log buffer, in bytes. By default, or if the value is set to 0, a size of 32K is used. The size of the log file (see DbEnv.set_lg_max) must be at least four times the size of the the in-memory log buffer.

Log information is stored in-memory until the storage space fills up or transaction commit forces the information to be flushed to stable storage. In the presence of long-running transactions or transactions producing large amounts of data, larger buffer sizes can increase throughput.

The DbEnv.set_lg_bsize method configures a database environment, not only operations performed using the specified DbEnv handle.

The DbEnv.set_lg_bsize interface may not be called after the DbEnv.open interface is called. If the database environment already exists when DbEnv.open is called, the information specified to DbEnv.set_lg_bsize will be ignored.

The DbEnv.set_lg_bsize method throws an exception that encapsulates a non-zero error value on failure.

The database environment's log buffer size may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_lg_bsize", one or more whitespace characters, and the size in bytes. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

# Errors

The DbEnv.set_lg_bsize method may fail and throw an exception encapsulating a non-zero error for the following conditions:

EINVAL
  An invalid flag value or parameter was specified.

  Called after DbEnv.open was called.

  The size of the log file is less than four times the size of the in-memory log buffer.

The DbEnv.set_lg_bsize method may fail and throw an exception for errors specified for other Berkeley DB and C library or system methods. If a catastrophic error has occurred, the DbEnv.set_lg_bsize method may fail and throw a DbRunRecoveryException, in which case all subsequent Berkeley DB calls will fail in the same way.

# Class

DbEnv, DbLogc, DbLsn

# See Also

Logging Subsystem and Related Methods`

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