Library Version 11.2.5.3

DB_ENV->set_backup_config()
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DB_ENV->set_backup_config()

#include <db.h>
 
DB_ENV->set_backup_config(DB_ENV, db_backup_config_t option, 
                          u_int32_t value);

The DB_ENV->set_backup_config() method configures tuning parameters for the hot backup APIs. See the DB_ENV->backup() and DB_ENV->dbbackup() methods for a description of the hot backup APIs.

The DB_ENV->set_backup_config() method configures operations performed using the specified DB_ENV handle, not all operations performed on the underlying database environment.

The DB_ENV->set_backup_config() method may be called at any time during the life of the application.

The DB_ENV->set_backup_config() method returns a non-zero error value on failure and 0 on success.

Parameters

option

The option parameter identifies the backup parameter to be modified. It must be one of the following:

  • DB_BACKUP_WRITE_DIRECT

    Turning this on causes direct I/O to be used when writing pages to the disk. For some environments, direct I/O can provide faster write throughput, but usually it is slower because the OS buffer pool offers asynchronous activity.

    By default, this option is turned off.

  • DB_BACKUP_READ_COUNT

    Configures the number of pages to read before pausing. Increasing this value increases the amount of I/O the backup process performs for any given time interval. If your application is already heavily I/O bound, setting this value to a lower number may help to improve your overall data throughput by reducing the I/O demands placed on your system.

    By default, all pages are read without a pause.

  • DB_BACKUP_READ_SLEEP

    Configures the number of microseconds to sleep between batches of reads. Increasing this value decreases the amount of I/O the backup process performs for any given time interval. If your application is already heavily I/O bound, setting this value to a higher number may help to improve your overall data throughput by reducing the I/O demands placed on your system.

  • DB_BACKUP_SIZE

    Configures the size of the buffer, in bytes, to read from the database. Default is 1 megabyte.

value

The value parameter sets the configuration value for the option identified by the option parameter. For those options which can only be turned on or off, this parameter should be set to 0 for off and 1 for on. Otherwise, set this parameter to an integer value that represents the number of units for which you are configuring the backup APIs.

Class

DB_ENV,

See Also

Database Environments and Related Methods, DB_ENV->get_backup_config(), DB_ENV->backup(), DB_ENV->dbbackup()

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