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615 lines
22 KiB
HTML
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
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<title>DB_ENV->lock_stat()</title>
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<link rel="stylesheet" href="apiReference.css" type="text/css" />
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<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
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<link rel="start" href="index.html" title="Berkeley DB C API Reference" />
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<link rel="up" href="lock.html" title="Chapter 6. The DB_LOCK Handle" />
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<link rel="prev" href="lockput.html" title="DB_ENV->lock_put()" />
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<link rel="next" href="lockstat_print.html" title="DB_ENV->lock_stat_print()" />
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</head>
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<body>
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<div xmlns="" class="navheader">
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<div class="libver">
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<p>Library Version 11.2.5.3</p>
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</div>
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<table width="100%" summary="Navigation header">
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<tr>
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<th colspan="3" align="center">DB_ENV->lock_stat()</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="lockput.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 6.
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The DB_LOCK Handle
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="lockstat_print.html">Next</a></td>
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</tr>
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</table>
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<hr />
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</div>
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<div class="sect1" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h2 class="title" style="clear: both"><a id="lockstat"></a>DB_ENV->lock_stat()</h2>
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</div>
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</div>
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</div>
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<pre class="programlisting">#include <db.h>
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int
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DB_ENV->lock_stat(DB_ENV *env, DB_LOCK_STAT **statp, u_int32_t flags); </pre>
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<p>
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The <code class="methodname">DB_ENV->lock_stat()</code> method returns the locking subsystem
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statistics.
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</p>
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<p>
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The <code class="methodname">DB_ENV->lock_stat()</code> method creates a statistical structure of
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type DB_LOCK_STAT and copies a pointer to it into a user-specified
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memory location.
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</p>
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<p>
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Statistical structures are stored in allocated memory. If
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application-specific allocation routines have been declared (see
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<a class="xref" href="envset_alloc.html" title="DB_ENV->set_alloc()">DB_ENV->set_alloc()</a>
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for more information), they are used to allocate the memory;
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otherwise, the standard C library <span class="bold"><strong>malloc</strong></span>(3) is used. The caller is responsible
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for deallocating the memory. To deallocate the memory, free the
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memory reference; references inside the returned memory need not be
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individually freed.
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</p>
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<p>
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The following DB_LOCK_STAT fields will be filled in:
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</p>
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<div class="itemizedlist">
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<ul type="disc">
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_cur_maxid;</strong></span>
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</p>
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<p>
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The current maximum unused locker ID.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_hash_len;</strong></span>
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</p>
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<p>
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Maximum length of a lock hash bucket.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_id;</strong></span>
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</p>
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<p>
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The last allocated locker ID.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_initlocks;</strong></span>
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</p>
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<p>
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The initial number of locks allocated in the lock
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table.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_initlockers;</strong></span>
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</p>
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<p>
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The initial number of lockers allocated in the lock
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table.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_initobjects;</strong></span>
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</p>
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<p>
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The initial number of lock objects allocated in the lock
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table.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_lock_nowait;</strong></span>
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</p>
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<p>
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The number of lock requests not immediately available due to
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conflicts, for which the thread of control did not wait.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_lock_wait;</strong></span>
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</p>
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<p>
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The number of lock requests not immediately available due to
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conflicts, for which the thread of control waited.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_lockers_nowait;</strong></span>
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</p>
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<p>
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The number of requests to allocate or deallocate a locker for which
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the thread of control did not wait.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_lockers_wait;</strong></span>
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</p>
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<p>
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The number of requests to allocate or deallocate a locker for which
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the thread of control waited.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_lockers;</strong></span>
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</p>
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<p>
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The current number of lockers allocated in the lock table.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_locks;</strong></span>
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</p>
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<p>
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The current number of locks allocated in the lock table.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_locksteals;</strong></span>
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</p>
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<p>
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The maximum number of locks stolen by an empty partition.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>db_timeout_t st_locktimeout;</strong></span>
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</p>
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<p>
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Lock timeout value.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_maxhlocks;</strong></span>
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</p>
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<p>
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The maximum number of locks in any hash bucket at any one time.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_maxhobjects;</strong></span>
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</p>
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<p>
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The maximum number of objects in any hash bucket at any one time.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_maxlockers;</strong></span>
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</p>
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<p>
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The maximum number of lockers possible.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_maxlocks;</strong></span>
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</p>
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<p>
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The maximum number of locks possible.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_maxlsteals;</strong></span>
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</p>
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<p>
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The maximum number of lock steals for any one partition.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_maxnlockers;</strong></span>
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</p>
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<p>
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The maximum number of lockers at any one time.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_maxnobjects;</strong></span>
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</p>
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<p>
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The maximum number of lock objects at any one time. Note that if there
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is more than one partition this is the sum of the maximum across all
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partitions.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_maxnlocks;</strong></span>
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</p>
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<p>
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The maximum number of locks at any one time. Note that if there is
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more than one partition, this is the sum of the maximum across all
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partitions.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_maxobjects;</strong></span>
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</p>
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<p>
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The maximum number of lock objects possible.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_maxosteals;</strong></span>
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</p>
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<p>
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The maximum number of object steals for any one partition.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_ndeadlocks;</strong></span>
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</p>
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<p>
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The number of deadlocks.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_ndowngrade;</strong></span>
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</p>
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<p>
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The total number of locks downgraded.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_nlockers;</strong></span>
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</p>
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<p>
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The number of current lockers.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_nlocks;</strong></span>
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</p>
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<p>
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The number of current locks.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_nlocktimeouts;</strong></span>
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</p>
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<p>
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The number of lock requests that have timed out.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>int st_nmodes;</strong></span>
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</p>
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<p>
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The number of lock modes.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_nobjects;</strong></span>
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</p>
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<p>
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The number of current lock objects.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_nreleases;</strong></span>
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</p>
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<p>
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The total number of locks released.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_nrequests;</strong></span>
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</p>
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<p>
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The total number of locks requested.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_ntxntimeouts;</strong></span>
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</p>
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<p>
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The number of transactions that have timed out. This value is also a
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component of <span class="bold"><strong>st_ndeadlocks</strong></span>, the total
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number of deadlocks detected.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_nupgrade;</strong></span>
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</p>
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<p>
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The total number of locks upgraded.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>u_int32_t st_objects;</strong></span>
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</p>
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<p>
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The current number of lock objects allocated in the lock
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table.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_objectsteals;</strong></span>
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</p>
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<p>
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The maximum number of objects stolen by an empty partition.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_objs_nowait;</strong></span>
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</p>
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<p>
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The number of requests to allocate or deallocate an object for which
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the thread of control did not wait.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_objs_wait;</strong></span>
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</p>
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<p>
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The number of requests to allocate or deallocate an object for which
|
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the thread of control waited.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_part_max_nowait;</strong></span>
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</p>
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<p>
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The number of times that a thread of control was able to obtain any
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one lock partition mutex without waiting.
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</p>
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</li>
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<li>
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<p>
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<span class="bold"><strong>uintmax_t st_part_max_wait;</strong></span>
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</p>
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<p>
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The maximum number of times that a thread of control was forced to
|
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wait before obtaining any one lock partition mutex.
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</p>
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</li>
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<li>
|
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<p>
|
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<span class="bold"><strong>uintmax_t st_part_nowait;</strong></span>
|
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</p>
|
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<p>
|
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The number of times that a thread of control was able to obtain the
|
||
lock partition mutex without waiting.
|
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</p>
|
||
</li>
|
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<li>
|
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<p>
|
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<span class="bold"><strong>uintmax_t st_part_wait;</strong></span>
|
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</p>
|
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<p>
|
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The number of times that a thread of control was forced to wait before
|
||
obtaining the lock partition mutex.
|
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</p>
|
||
</li>
|
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<li>
|
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<p>
|
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<span class="bold"><strong>u_int32_t st_partitions;</strong></span>
|
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</p>
|
||
<p>
|
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The number of lock table partitions.
|
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</p>
|
||
</li>
|
||
<li>
|
||
<p>
|
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<span class="bold"><strong>uintmax_t st_region_nowait;</strong></span>
|
||
</p>
|
||
<p>
|
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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="idp60673232"></a>Parameters</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="sect3" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h4 class="title"><a id="idp60630864"></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="idp60684384"></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="idp60689224"></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="idp60657744"></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="idp60691912"></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="idp60694288"></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>
|