<!--$Id: lock_stat.so,v 10.68 2007/06/22 16:57:15 bostic Exp $--> <!--Copyright (c) 1997,2007 Oracle. All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: DbEnv::lock_stat</title> <meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> <meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> </head> <body bgcolor=white> <table width="100%"><tr valign=top> <td> <h3>DbEnv::lock_stat</h3> </td> <td align=right> <a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a> <a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a></td> </tr></table> <hr size=1 noshade> <tt> <h3><pre> #include <db_cxx.h> <p> int DbEnv::lock_stat(DB_LOCK_STAT **statp, u_int32_t flags); <p> int DbEnv::lock_stat_print(u_int32_t flags); </pre></h3> <hr size=1 noshade> <h3>Description: DbEnv::lock_stat</h3> <p>The DbEnv::lock_stat method returns the locking subsystem statistics.</p> <p>The DbEnv::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> <p>Statistical structures are stored in allocated memory. If application-specific allocation routines have been declared (see <a href="../api_cxx/env_set_alloc.html">DbEnv::set_alloc</a> for more information), they are used to allocate the memory; otherwise, the standard C library <b>malloc</b>(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.</p> <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_nupgrade;<dd>The total number of locks upgraded. <dt>u_int32_t st_ndowngrade;<dd>The total number of locks downgraded. <dt>u_int32_t st_lock_wait;<dd>The number of lock requests not immediately available due to conflicts, for which the thread of control waited. <dt>u_int32_t st_lock_nowait;<dd>The number of lock requests not immediately available due to conflicts, for which the thread of control did not wait. <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 lock requests 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_objs_wait;<dd>The number of requests to allocate or deallocate an object for which the thread of control waited. <dt>u_int32_t st_objs_nowait;<dd>The number of requests to allocate or deallocate an object for which the thread of control did not wait. <dt>u_int32_t st_lockers_wait;<dd>The number of requests to allocate or deallocate a locker for which the thread of control waited. <dt>u_int32_t st_lockers_nowait;<dd>The number of requests to allocate or deallocate a locker for which the thread of control did not wait. <dt>u_int32_t st_locks_wait;<dd>The number of requests to allocate or deallocate a lock structure for which the thread of control waited. <dt>u_int32_t st_locks_nowait;<dd>The number of requests to allocate or deallocate a lock structure for which the thread of control did not wait. <dt>u_int32_t st_hash_len;<dd>Maximum length of a lock hash bucket. <dt>roff_t st_regsize;<dd>The size of the lock region, in bytes. <dt>u_int32_t st_region_wait;<dd>The number of times that a thread of control was forced to wait before obtaining the lock region mutex. <dt>u_int32_t st_region_nowait;<dd>The number of times that a thread of control was able to obtain the lock region mutex without waiting. </dl> <p>The DbEnv::lock_stat method may not be called before the <a href="../api_cxx/env_open.html">DbEnv::open</a> method has been called.</p> <p>The DbEnv::lock_stat method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success. </p> <h3>Parameters</h3> <dl compact> <dt><b>flags</b><dd>The <b>flags</b> parameter must be set to 0 or the following value: <dl compact> <dt><a name="DB_STAT_CLEAR">DB_STAT_CLEAR</a><dd>Reset statistics after returning their values. </dl> <dt><b>statp</b><dd>The <b>statp</b> parameter references memory into which a pointer to the allocated statistics structure is copied. </dl> <h3>Errors</h3> <p>The DbEnv::lock_stat method may fail and throw <a href="../api_cxx/except_class.html">DbException</a>, encapsulating one of the following non-zero errors, or return one of the following non-zero errors:</p> <dl compact> <dt>EINVAL<dd>An invalid flag value or parameter was specified. </dl> <hr size=1 noshade> <h3>Description: DbEnv::lock_stat_print</h3> <p>The DbEnv::lock_stat_print method displays the locking subsystem statistical information, as described for the DbEnv::lock_stat method. The information is printed to a specified output channel (see the <a href="../api_cxx/env_set_msgfile.html">DbEnv::set_msgfile</a> method for more information), or passed to an application callback function (see the <a href="../api_cxx/env_set_msgcall.html">DbEnv::set_msgcall</a> method for more information).</p> <p>The DbEnv::lock_stat_print method may not be called before the <a href="../api_cxx/env_open.html">DbEnv::open</a> method has been called.</p> <p>The DbEnv::lock_stat_print method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success. </p> <h3>Parameters</h3> <dl compact> <dt><b>flags</b><dd>The <b>flags</b> parameter must be set to 0 or by bitwise inclusively <b>OR</b>'ing together one or more of the following values: <dl compact> <dt><a name="DB_STAT_ALL">DB_STAT_ALL</a><dd>Display all available information. <dt><a name="DB_STAT_CLEAR">DB_STAT_CLEAR</a><dd>Reset statistics after displaying their values. <dt><a name="DB_STAT_LOCK_CONF">DB_STAT_LOCK_CONF</a><dd>Display the lock conflict matrix. <dt><a name="DB_STAT_LOCK_LOCKERS">DB_STAT_LOCK_LOCKERS</a><dd>Display the lockers within hash chains. <dt><a name="DB_STAT_LOCK_OBJECTS">DB_STAT_LOCK_OBJECTS</a><dd>Display the lock objects within hash chains. <dt><a name="DB_STAT_LOCK_PARAMS">DB_STAT_LOCK_PARAMS</a><dd>Display the locking subsystem parameters. </dl> </dl> <hr size=1 noshade> <h3>Class</h3> <a href="../api_cxx/env_class.html">DbEnv</a>, <a href="../api_cxx/lock_class.html">DbLock</a> <h3>See Also</h3> <a href="../api_cxx/lock_list.html">Locking Subsystem and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../api_cxx/api_core.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1>Copyright (c) 1996,2007 Oracle. 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