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<!--$Id: lock_stat.so,v 10.71 2008/03/21 18:20:27 ubell Exp $--> <!--Copyright (c) 1997,2008 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> <b>DbEnv::lock_stat</b> </td> <td align=right> <a href="../../db4-devel-4.7.25/api_cxx/api_core.html"><img src="../../db4-devel-4.7.25/images/api.gif" alt="API"></a> <a href="../../db4-devel-4.7.25/ref/toc.html"><img src="../../db4-devel-4.7.25/images/ref.gif" alt="Ref"></a></td> </tr></table> <hr size=1 noshade> <tt> <b><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></b> <hr size=1 noshade> <b>Description: DbEnv::lock_stat</b> <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="../../db4-devel-4.7.25/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> <br> <b>u_int32_t st_id;</b><ul compact><li>The last allocated locker ID.</ul> <b>u_int32_t st_cur_maxid;</b><ul compact><li>The current maximum unused locker ID.</ul> <b>u_int32_t st_nmodes;</b><ul compact><li>The number of lock modes.</ul> <b>u_int32_t st_maxlocks;</b><ul compact><li>The maximum number of locks possible.</ul> <b>u_int32_t st_maxlockers;</b><ul compact><li>The maximum number of lockers possible.</ul> <b>u_int32_t st_maxobjects;</b><ul compact><li>The maximum number of lock objects possible.</ul> <b>u_int32_t st_partitions;</b><ul compact><li>The number of lock table partitions.</ul> <b>u_int32_t st_nlocks;</b><ul compact><li>The number of current locks.</ul> <b>u_int32_t st_maxnlocks;</b><ul compact><li>The maximum number of locks at any one time. Note that if there is more than one partition, this is the sum of the maximum across all partitions.</ul> <b>u_int32_t st_maxhlocks;</b><ul compact><li>The maximum number of locks in any hash bucket at any one time.</ul> <b>u_int32_t st_locksteals;</b><ul compact><li>The maximum number of locks stolen by for an empty partition.</ul> <b>u_int32_t st_maxlsteals;</b><ul compact><li>The maximum number of lock steals for any one partition.</ul> <b>u_int32_t st_nlockers;</b><ul compact><li>The number of current lockers.</ul> <b>u_int32_t st_maxnlockers;</b><ul compact><li>The maximum number of lockers at any one time.</ul> <b>u_int32_t st_nobjects;</b><ul compact><li>The number of current lock objects.</ul> <b>u_int32_t st_maxnobjects;</b><ul compact><li>The maximum number of lock objects at any one time. Note that if there is more than one partition this is the sum of the maximum across all partitions.</ul> <b>u_int32_t st_maxhobjects;</b><ul compact><li>The maximum number of objects in any hash bucket at any one time.</ul> <b>u_int32_t st_objectsteals;</b><ul compact><li>The maximum number of objects stolen by for an empty partition.</ul> <b>u_int32_t st_maxosteals;</b><ul compact><li>The maximum number of object steals for any one partition.</ul> <b>u_int32_t st_nrequests;</b><ul compact><li>The total number of locks requested.</ul> <b>u_int32_t st_nreleases;</b><ul compact><li>The total number of locks released.</ul> <b>u_int32_t st_nupgrade;</b><ul compact><li>The total number of locks upgraded.</ul> <b>u_int32_t st_ndowngrade;</b><ul compact><li>The total number of locks downgraded.</ul> <b>u_int32_t st_lock_wait;</b><ul compact><li>The number of lock requests not immediately available due to conflicts, for which the thread of control waited.</ul> <b>u_int32_t st_lock_nowait;</b><ul compact><li>The number of lock requests not immediately available due to conflicts, for which the thread of control did not wait.</ul> <b>u_int32_t st_ndeadlocks;</b><ul compact><li>The number of deadlocks.</ul> <b>u_int32_t st_locktimeout;</b><ul compact><li>Lock timeout value.</ul> <b>u_int32_t st_nlocktimeouts;</b><ul compact><li>The number of lock requests that have timed out.</ul> <b>u_int32_t st_txntimeout;</b><ul compact><li>Transaction timeout value.</ul> <b>u_int32_t st_ntxntimeouts;</b><ul compact><li>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.</ul> <b>u_int32_t st_objs_wait;</b><ul compact><li>The number of requests to allocate or deallocate an object for which the thread of control waited.</ul> <b>u_int32_t st_objs_nowait;</b><ul compact><li>The number of requests to allocate or deallocate an object for which the thread of control did not wait.</ul> <b>u_int32_t st_lockers_wait;</b><ul compact><li>The number of requests to allocate or deallocate a locker for which the thread of control waited.</ul> <b>u_int32_t st_lockers_nowait;</b><ul compact><li>The number of requests to allocate or deallocate a locker for which the thread of control did not wait.</ul> <b>u_int32_t st_hash_len;</b><ul compact><li>Maximum length of a lock hash bucket.</ul> <b>roff_t st_regsize;</b><ul compact><li>The size of the lock region, in bytes.</ul> <b>u_int32_t st_part_wait;</b><ul compact><li>The number of times that a thread of control was forced to wait before obtaining the lock partition mutex.</ul> <b>u_int32_t st_part_nowait;</b><ul compact><li>The number of times that a thread of control was able to obtain the lock partition mutex without waiting.</ul> <b>u_int32_t st_part_max_wait;</b><ul compact><li>The maximum number of times that a thread of control was forced to wait before obtaining any one lock partition mutex.</ul> <b>u_int32_t st_part_max_nowait;</b><ul compact><li>The number of times that a thread of control was able to obtain any one lock partition mutex without waiting.</ul> <b>u_int32_t st_region_wait;</b><ul compact><li>The number of times that a thread of control was forced to wait before obtaining the lock region mutex.</ul> <b>u_int32_t st_region_nowait;</b><ul compact><li>The number of times that a thread of control was able to obtain the lock region mutex without waiting.</ul> <br> <p>The DbEnv::lock_stat method may not be called before the <a href="../../db4-devel-4.7.25/api_cxx/env_open.html">DbEnv::open</a> method is 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> <b>Parameters</b> <br> <b>flags</b><ul compact><li>The <b>flags</b> parameter must be set to 0 or the following value: <br> <b><a name="DB_STAT_CLEAR">DB_STAT_CLEAR</a></b><ul compact><li>Reset statistics after returning their values.</ul> <br></ul> <b>statp</b><ul compact><li>The <b>statp</b> parameter references memory into which a pointer to the allocated statistics structure is copied.</ul> <br> <br><b>Errors</b> <p>The DbEnv::lock_stat method may fail and throw <a href="../../db4-devel-4.7.25/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> <br> <b>EINVAL</b><ul compact><li>An invalid flag value or parameter was specified.</ul> <br> <hr size=1 noshade> <b>Description: DbEnv::lock_stat_print</b> <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="../../db4-devel-4.7.25/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="../../db4-devel-4.7.25/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="../../db4-devel-4.7.25/api_cxx/env_open.html">DbEnv::open</a> method is 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> <b>Parameters</b> <br> <b>flags</b><ul compact><li>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: <br> <b><a name="DB_STAT_ALL">DB_STAT_ALL</a></b><ul compact><li>Display all available information.</ul> <b><a name="DB_STAT_CLEAR">DB_STAT_CLEAR</a></b><ul compact><li>Reset statistics after displaying their values.</ul> <b><a name="DB_STAT_LOCK_CONF">DB_STAT_LOCK_CONF</a></b><ul compact><li>Display the lock conflict matrix.</ul> <b><a name="DB_STAT_LOCK_LOCKERS">DB_STAT_LOCK_LOCKERS</a></b><ul compact><li>Display the lockers within hash chains.</ul> <b><a name="DB_STAT_LOCK_OBJECTS">DB_STAT_LOCK_OBJECTS</a></b><ul compact><li>Display the lock objects within hash chains.</ul> <b><a name="DB_STAT_LOCK_PARAMS">DB_STAT_LOCK_PARAMS</a></b><ul compact><li>Display the locking subsystem parameters.</ul> <br></ul> <br> <hr size=1 noshade> <br><b>Class</b> <a href="../../db4-devel-4.7.25/api_cxx/env_class.html">DbEnv</a>, <a href="../../db4-devel-4.7.25/api_cxx/lock_class.html">DbLock</a> <br><b>See Also</b> <a href="../../db4-devel-4.7.25/api_cxx/lock_list.html">Locking Subsystem and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../../db4-devel-4.7.25/api_cxx/api_core.html"><img src="../../db4-devel-4.7.25/images/api.gif" alt="API"></a><a href="../../db4-devel-4.7.25/ref/toc.html"><img src="../../db4-devel-4.7.25/images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1>Copyright (c) 1996,2008 Oracle. 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