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DB_ENV->lock_stat

API Ref

#include <db.h>

int DB_ENV->lock_stat(DB_ENV *env, DB_LOCK_STAT **statp, u_int32_t flags);

int DB_ENV->lock_stat_print(DB_ENV *env, u_int32_t flags);


Description: DB_ENV->lock_stat

The DB_ENV->lock_stat method returns the locking subsystem statistics.

The DB_ENV->lock_stat method creates a statistical structure of type DB_LOCK_STAT and copies a pointer to it into a user-specified memory location.

Statistical structures are stored in allocated memory. If application-specific allocation routines have been declared (see DB_ENV->set_alloc for more information), they are used to allocate the memory; otherwise, the standard C library malloc(3) is used. The caller is responsible for deallocating the memory. To deallocate the memory, free the memory reference; references inside the returned memory need not be individually freed.

The following DB_LOCK_STAT fields will be filled in:

u_int32_t st_id;
The last allocated locker ID.
u_int32_t st_cur_maxid;
The current maximum unused locker ID.
u_int32_t st_nmodes;
The number of lock modes.
u_int32_t st_maxlocks;
The maximum number of locks possible.
u_int32_t st_maxlockers;
The maximum number of lockers possible.
u_int32_t st_maxobjects;
The maximum number of lock objects possible.
u_int32_t st_nlocks;
The number of current locks.
u_int32_t st_maxnlocks;
The maximum number of locks at any one time.
u_int32_t st_nlockers;
The number of current lockers.
u_int32_t st_maxnlockers;
The maximum number of lockers at any one time.
u_int32_t st_nobjects;
The number of current lock objects.
u_int32_t st_maxnobjects;
The maximum number of lock objects at any one time.
u_int32_t st_nrequests;
The total number of locks requested.
u_int32_t st_nreleases;
The total number of locks released.
u_int32_t st_nupgrade;
The total number of locks upgraded.
u_int32_t st_ndowngrade;
The total number of locks downgraded.
u_int32_t st_lock_wait;
The number of lock requests not immediately available due to conflicts, for which the thread of control waited.
u_int32_t st_lock_nowait;
The number of lock requests not immediately available due to conflicts, for which the thread of control did not wait.
u_int32_t st_ndeadlocks;
The number of deadlocks.
u_int32_t st_locktimeout;
Lock timeout value.
u_int32_t st_nlocktimeouts;
The number of lock requests that have timed out.
u_int32_t st_txntimeout;
Transaction timeout value.
u_int32_t st_ntxntimeouts;
The number of transactions that have timed out. This value is also a component of st_ndeadlocks, the total number of deadlocks detected.
roff_t st_regsize;
The size of the lock region, in bytes.
u_int32_t st_region_wait;
The number of times that a thread of control was forced to wait before obtaining the lock region mutex.
u_int32_t st_region_nowait;
The number of times that a thread of control was able to obtain the lock region mutex without waiting.

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

Parameters

flags
The flags parameter must be set to 0 or the following value:
DB_STAT_CLEAR
Reset statistics after returning their values.
statp
The statp parameter references memory into which a pointer to the allocated statistics structure is copied.

Errors

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

EINVAL
An invalid flag value or parameter was specified.

Description: DB_ENV->lock_stat_print

The DB_ENV->lock_stat_print method prints diagnostic information to the output channel described by the DB_ENV->set_msgfile method.

The DB_ENV->lock_stat_print method may not be called before the DB_ENV->open method has been called.

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

Parameters

flags
The flags parameter must be set by bitwise inclusively OR'ing together one or more of the following values:
DB_STAT_ALL
Display all available information.
DB_STAT_LOCK_CONF
Display the lock conflict matrix.
DB_STAT_LOCK_LOCKERS
Display the lockers within hash chains.
DB_STAT_LOCK_OBJECTS
Display the lock objects within hash chains.
DB_STAT_LOCK_PARAMS
Display the locking subsystem parameters.

Class

DB_ENV, DB_LOCK

See Also

Locking Subsystem and Related Methods

APIRef

Copyright (c) 1996-2005 Sleepycat Software, Inc. - All rights reserved.