<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>DB_ENV->lock_stat()</title> <link rel="stylesheet" href="apiReference.css" type="text/css" /> <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> <link rel="start" href="index.html" title="Berkeley DB C API Reference" /> <link rel="up" href="lock.html" title="Chapter 6. The DB_LOCK Handle" /> <link rel="prev" href="lockput.html" title="DB_ENV->lock_put()" /> <link rel="next" href="lockstat_print.html" title="DB_ENV->lock_stat_print()" /> </head> <body> <div xmlns="" class="navheader"> <div class="libver"> <p>Library Version 11.2.5.3</p> </div> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">DB_ENV->lock_stat()</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="lockput.html">Prev</a> </td> <th width="60%" align="center">Chapter 6. The DB_LOCK Handle </th> <td width="20%" align="right"> <a accesskey="n" href="lockstat_print.html">Next</a></td> </tr> </table> <hr /> </div> <div class="sect1" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h2 class="title" style="clear: both"><a id="lockstat"></a>DB_ENV->lock_stat()</h2> </div> </div> </div> <pre class="programlisting">#include <db.h> int DB_ENV->lock_stat(DB_ENV *env, DB_LOCK_STAT **statp, u_int32_t flags); </pre> <p> The <code class="methodname">DB_ENV->lock_stat()</code> method returns the locking subsystem statistics. </p> <p> The <code class="methodname">DB_ENV->lock_stat()</code> 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 class="xref" href="envset_alloc.html" title="DB_ENV->set_alloc()">DB_ENV->set_alloc()</a> for more information), they are used to allocate the memory; otherwise, the standard C library <span class="bold"><strong>malloc</strong></span>(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> <div class="itemizedlist"> <ul type="disc"> <li> <p> <span class="bold"><strong>u_int32_t st_cur_maxid;</strong></span> </p> <p> The current maximum unused locker ID. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_hash_len;</strong></span> </p> <p> Maximum length of a lock hash bucket. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_id;</strong></span> </p> <p> The last allocated locker ID. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_initlocks;</strong></span> </p> <p> The initial number of locks allocated in the lock table. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_initlockers;</strong></span> </p> <p> The initial number of lockers allocated in the lock table. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_initobjects;</strong></span> </p> <p> The initial number of lock objects allocated in the lock table. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_lock_nowait;</strong></span> </p> <p> The number of lock requests not immediately available due to conflicts, for which the thread of control did not wait. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_lock_wait;</strong></span> </p> <p> The number of lock requests not immediately available due to conflicts, for which the thread of control waited. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_lockers_nowait;</strong></span> </p> <p> The number of requests to allocate or deallocate a locker for which the thread of control did not wait. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_lockers_wait;</strong></span> </p> <p> The number of requests to allocate or deallocate a locker for which the thread of control waited. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_lockers;</strong></span> </p> <p> The current number of lockers allocated in the lock table. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_locks;</strong></span> </p> <p> The current number of locks allocated in the lock table. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_locksteals;</strong></span> </p> <p> The maximum number of locks stolen by an empty partition. </p> </li> <li> <p> <span class="bold"><strong>db_timeout_t st_locktimeout;</strong></span> </p> <p> Lock timeout value. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_maxhlocks;</strong></span> </p> <p> The maximum number of locks in any hash bucket at any one time. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_maxhobjects;</strong></span> </p> <p> The maximum number of objects in any hash bucket at any one time. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_maxlockers;</strong></span> </p> <p> The maximum number of lockers possible. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_maxlocks;</strong></span> </p> <p> The maximum number of locks possible. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_maxlsteals;</strong></span> </p> <p> The maximum number of lock steals for any one partition. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_maxnlockers;</strong></span> </p> <p> The maximum number of lockers at any one time. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_maxnobjects;</strong></span> </p> <p> 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. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_maxnlocks;</strong></span> </p> <p> 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. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_maxobjects;</strong></span> </p> <p> The maximum number of lock objects possible. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_maxosteals;</strong></span> </p> <p> The maximum number of object steals for any one partition. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_ndeadlocks;</strong></span> </p> <p> The number of deadlocks. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_ndowngrade;</strong></span> </p> <p> The total number of locks downgraded. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_nlockers;</strong></span> </p> <p> The number of current lockers. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_nlocks;</strong></span> </p> <p> The number of current locks. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_nlocktimeouts;</strong></span> </p> <p> The number of lock requests that have timed out. </p> </li> <li> <p> <span class="bold"><strong>int st_nmodes;</strong></span> </p> <p> The number of lock modes. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_nobjects;</strong></span> </p> <p> The number of current lock objects. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_nreleases;</strong></span> </p> <p> The total number of locks released. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_nrequests;</strong></span> </p> <p> The total number of locks requested. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_ntxntimeouts;</strong></span> </p> <p> The number of transactions that have timed out. This value is also a component of <span class="bold"><strong>st_ndeadlocks</strong></span>, the total number of deadlocks detected. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_nupgrade;</strong></span> </p> <p> The total number of locks upgraded. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_objects;</strong></span> </p> <p> The current number of lock objects allocated in the lock table. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_objectsteals;</strong></span> </p> <p> The maximum number of objects stolen by an empty partition. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_objs_nowait;</strong></span> </p> <p> The number of requests to allocate or deallocate an object for which the thread of control did not wait. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_objs_wait;</strong></span> </p> <p> The number of requests to allocate or deallocate an object for which the thread of control waited. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_part_max_nowait;</strong></span> </p> <p> The number of times that a thread of control was able to obtain any one lock partition mutex without waiting. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_part_max_wait;</strong></span> </p> <p> The maximum number of times that a thread of control was forced to wait before obtaining any one lock partition mutex. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_part_nowait;</strong></span> </p> <p> The number of times that a thread of control was able to obtain the lock partition mutex without waiting. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_part_wait;</strong></span> </p> <p> The number of times that a thread of control was forced to wait before obtaining the lock partition mutex. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_partitions;</strong></span> </p> <p> The number of lock table partitions. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_region_nowait;</strong></span> </p> <p> The number of times that a thread of control was able to obtain the lock region mutex without waiting. </p> </li> <li> <p> <span class="bold"><strong>uintmax_t st_region_wait;</strong></span> </p> <p> The number of times that a thread of control was forced to wait before obtaining the lock region mutex. </p> </li> <li> <p> <span class="bold"><strong>roff_t st_regsize;</strong></span> </p> <p> The region size, in bytes. </p> </li> <li> <p> <span class="bold"><strong>u_int32_t st_tablesize;</strong></span> </p> <p> The size of the object hash table. </p> </li> <li> <p> <span class="bold"><strong>db_timeout_t st_txntimeout;</strong></span> </p> <p> Transaction timeout value. </p> </li> </ul> </div> <p> The <code class="methodname">DB_ENV->lock_stat()</code> method may not be called before the <a class="xref" href="envopen.html" title="DB_ENV->open()">DB_ENV->open()</a> method is called. </p> <p> The <code class="methodname">DB_ENV->lock_stat()</code> method returns a non-zero error value on failure and 0 on success. </p> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp52651568"></a>Parameters</h3> </div> </div> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp52671496"></a>statp</h4> </div> </div> </div> <p> The <span class="bold"><strong>statp</strong></span> parameter references memory into which a pointer to the allocated statistics structure is copied. </p> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp52716272"></a>flags</h4> </div> </div> </div> <p> The <span class="bold"><strong>flags</strong></span> parameter must be set to 0 or the following value: </p> <div class="itemizedlist"> <ul type="disc"> <li> <p><a id="stat_DB_STAT_CLEAR"></a> <code class="literal">DB_STAT_CLEAR</code> </p> <p> Reset statistics after returning their values. </p> </li> </ul> </div> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp52721408"></a>Errors</h3> </div> </div> </div> <p> The <code class="methodname">DB_ENV->lock_stat()</code> <span> <span> method may fail and return one of the following non-zero errors: </span> </span> </p> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp52671752"></a>EINVAL</h4> </div> </div> </div> <p> An invalid flag value or parameter was specified. </p> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp52711328"></a>Class</h3> </div> </div> </div> <p> <a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a>, <a class="link" href="lock.html" title="Chapter 6. The DB_LOCK Handle">DB_LOCK</a> </p> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp52726296"></a>See Also</h3> </div> </div> </div> <p> <a class="xref" href="lock.html#locklist" title="Locking Subsystem and Related Methods">Locking Subsystem and Related Methods</a> </p> </div> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="lockput.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="lock.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="lockstat_print.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">DB_ENV->lock_put() </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> DB_ENV->lock_stat_print()</td> </tr> </table> </div> </body> </html>