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<title>Berkeley DB: DB_ENV->lock_stat</title>
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<h1>DB_ENV->lock_stat</h1>
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<h3><pre>
#include <db.h>
<p>
int
DB_ENV->lock_stat(DB_ENV *env, DB_LOCK_STAT **statp, u_int32_t flags);
</pre></h3>
<h1>Description</h1>
<p>The DB_ENV->lock_stat method returns the locking subsystem statistics.
<p>The <b>flags</b> value must be set to 0 or
the following value:
<p><dl compact>
<p><dt><a name="DB_STAT_CLEAR">DB_STAT_CLEAR</a><dd>Reset statistics after returning their values.
</dl>
<p>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.
<p>Statistical structures are created in allocated memory. If application-specific allocation
routines have been declared (see <a href="../api_c/env_set_alloc.html">DB_ENV->set_alloc</a> for more
information), they are used to allocate the memory; otherwise, the
library <b>malloc</b>(3) interface 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.
<p>The following DB_LOCK_STAT fields will be filled in:
<p><dl compact>
<dt>u_int32_t st_id;<dd>The last allocated locker ID.
<dt>u_int32_t st_cur_maxid;<dd>The current maximum unused locker ID.
<dt>u_int32_t st_nmodes;<dd>The number of lock modes.
<dt>u_int32_t st_maxlocks;<dd>The maximum number of locks possible.
<dt>u_int32_t st_maxlockers;<dd>The maximum number of lockers possible.
<dt>u_int32_t st_maxobjects;<dd>The maximum number of lock objects possible.
<dt>u_int32_t st_nlocks;<dd>The number of current locks.
<dt>u_int32_t st_maxnlocks;<dd>The maximum number of locks at any one time.
<dt>u_int32_t st_nlockers;<dd>The number of current lockers.
<dt>u_int32_t st_maxnlockers;<dd>The maximum number of lockers at any one time.
<dt>u_int32_t st_nobjects;<dd>The number of current lock objects.
<dt>u_int32_t st_maxnobjects;<dd>The maximum number of lock objects at any one time.
<dt>u_int32_t st_nrequests;<dd>The total number of locks requested.
<dt>u_int32_t st_nreleases;<dd>The total number of locks released.
<dt>u_int32_t st_nnowaits;<dd>The total number of lock requests failing because
<a href="../api_c/lock_vec.html#DB_LOCK_NOWAIT">DB_LOCK_NOWAIT</a> was set.
<dt>u_int32_t st_nconflicts;<dd>The total number of locks not immediately available due to conflicts.
<dt>u_int32_t st_ndeadlocks;<dd>The number of deadlocks.
<dt>u_int32_t st_locktimeout;<dd>Lock timeout value.
<dt>u_int32_t st_nlocktimeouts;<dd>The number of locks that have timed out.
<dt>u_int32_t st_txntimeout;<dd>Transaction timeout value.
<dt>u_int32_t st_ntxntimeouts;<dd>The number of transactions that have timed out. This value is also a
component of <b>st_ndeadlocks</b>, the total number of deadlocks
detected.
<dt>u_int32_t st_regsize;<dd>The size of the lock region.
<dt>u_int32_t st_region_wait;<dd>The number of times that a thread of control was forced to wait before
obtaining the region lock.
<dt>u_int32_t st_region_nowait;<dd>The number of times that a thread of control was able to obtain
the region lock without waiting.
</dl>
<p>The DB_ENV->lock_stat method returns a non-zero error value on failure and 0 on success.
<h1>Errors</h1>
<p>The DB_ENV->lock_stat method may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions.
If a catastrophic error has occurred, the DB_ENV->lock_stat method may fail and
return <a href="../ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a>,
in which case all subsequent Berkeley DB calls will fail in the same way.
<h1>Class</h1>
<a href="../api_c/env_class.html">DB_ENV</a>, <a href="../api_c/lock_class.html">DB_LOCK</a>
<h1>See Also</h1>
<a href="../api_c/lock_list.html">Locking Subsystem and Related Methods</a>
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