#include <db.h>

int
DB_ENV->set_mp_max_write(DB_ENV *env, int maxwrite, db_timeout_t maxwrite_sleep);

int
DB_ENV->get_mp_max_write(DB_ENV *env, int *maxwritep, db_timeout_t *maxwrite_sleepp);

The DB_ENV->set_mp_max_write method limits the number of sequential write operations scheduled by the library when flushing dirty pages from the cache.

The database environment's maximum number of sequential write operations may also be configured using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_mp_max_write", one or more whitespace characters, and the maximum number of sequential writes and the number of microseconds to sleep, also separated by whitespace characters. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

The DB_ENV->set_mp_max_write method configures a database environment, not only operations performed using the specified DB_ENV handle.

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

• The maximum number of sequential write operations scheduled by the library when flushing dirty pages from the cache, or 0 if there is no limitation on the number of sequential write operations.

• The number of microseconds the thread of control should pause before scheduling further write operations. It must be specified as an unsigned 32-bit number of microseconds, limiting the maximum pause to roughly 71 minutes.

The DB_ENV->set_mp_max_write method may fail and return one of the following non-zero errors:

• An invalid flag value or parameter was specified.

The DB_ENV->get_mp_max_write method returns the current maximum number of sequential write operations and microseconds to pause.

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

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

• The maxwritep parameter references memory into which the maximum number of sequential write operations is copied.

• The maxwrite_sleepp parameter references memory into which the microseconds to pause before scheduling further write operations is copied.