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| author | Lorry Tar Creator <lorry-tar-importer@baserock.org> | 2015-02-17 17:25:57 +0000 |
|---|---|---|
| committer | <> | 2015-03-17 16:26:24 +0000 |
| commit | 780b92ada9afcf1d58085a83a0b9e6bc982203d1 (patch) | |
| tree | 598f8b9fa431b228d29897e798de4ac0c1d3d970 /docs/programmer_reference/lock_config.html | |
| parent | 7a2660ba9cc2dc03a69ddfcfd95369395cc87444 (diff) | |
| download | berkeleydb-master.tar.gz | |
Diffstat (limited to 'docs/programmer_reference/lock_config.html')
| -rw-r--r-- | docs/programmer_reference/lock_config.html | 77 |
1 files changed, 43 insertions, 34 deletions
diff --git a/docs/programmer_reference/lock_config.html b/docs/programmer_reference/lock_config.html index 7659a481..d582e11d 100644 --- a/docs/programmer_reference/lock_config.html +++ b/docs/programmer_reference/lock_config.html @@ -14,7 +14,7 @@ <body> <div xmlns="" class="navheader"> <div class="libver"> - <p>Library Version 11.2.5.3</p> + <p>Library Version 12.1.6.1</p> </div> <table width="100%" summary="Navigation header"> <tr> @@ -22,9 +22,7 @@ </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="lock.html">Prev</a> </td> - <th width="60%" align="center">Chapter 16. - The Locking Subsystem - </th> + <th width="60%" align="center">Chapter 16. The Locking Subsystem </th> <td width="20%" align="right"> <a accesskey="n" href="lock_max.html">Next</a></td> </tr> </table> @@ -38,32 +36,44 @@ </div> </div> </div> - <p>The <a href="../api_reference/C/envset_lk_detect.html" class="olink">DB_ENV->set_lk_detect()</a> method specifies that the deadlock detector -should be run whenever a lock is about to block. This option provides -for rapid detection of deadlocks at the expense of potentially frequent -invocations of the deadlock detector. On a fast processor with a highly -contentious application where response time is critical, this is a good -choice. An option argument to the <a href="../api_reference/C/envset_lk_detect.html" class="olink">DB_ENV->set_lk_detect()</a> method -indicates which lock requests should be rejected.</p> - <p>The application can limit how long it blocks on a contested resource. -The <a href="../api_reference/C/envset_timeout.html" class="olink">DB_ENV->set_timeout()</a> method specifies the length of the timeout. -This value is checked whenever deadlock detection is performed, -so the accuracy of the timeout depends upon the frequency of -deadlock detection.</p> - <p>In general, when applications are not specifying lock and transaction -timeout values, the <a href="../api_reference/C/lockdetect.html#detect_DB_LOCK_DEFAULT" class="olink">DB_LOCK_DEFAULT</a> option is probably the -correct first choice, and other options should only be selected based -on evidence that they improve transaction throughput. If an application -has long-running transactions, <a href="../api_reference/C/lockdetect.html#detect_DB_LOCK_YOUNGEST" class="olink">DB_LOCK_YOUNGEST</a> will guarantee -that transactions eventually complete, but it may do so at the expense -of a large number of lock request rejections (and therefore, transaction -aborts).</p> - <p>The alternative to using the <a href="../api_reference/C/envset_lk_detect.html" class="olink">DB_ENV->set_lk_detect()</a> method is to -explicitly perform deadlock detection using the Berkeley DB -<a href="../api_reference/C/lockdetect.html" class="olink">DB_ENV->lock_detect()</a> method.</p> - <p>The <a href="../api_reference/C/envset_lk_conflicts.html" class="olink">DB_ENV->set_lk_conflicts()</a> method allows you to specify your own -locking conflicts matrix. This is an advanced configuration option, -and is almost never necessary.</p> + <p> + The <a href="../api_reference/C/envset_lk_detect.html" class="olink">DB_ENV->set_lk_detect()</a> method specifies that the deadlock + detector should be run whenever a lock is about to block. This + option provides for rapid detection of deadlocks at the + expense of potentially frequent invocations of the deadlock + detector. On a fast processor with a highly contentious + application where response time is critical, this is a good + choice. An option argument to the <a href="../api_reference/C/envset_lk_detect.html" class="olink">DB_ENV->set_lk_detect()</a> method + indicates which lock requests should be rejected. + </p> + <p> + The application can limit how long it blocks on a contested + resource. The <a href="../api_reference/C/envset_timeout.html" class="olink">DB_ENV->set_timeout()</a> method specifies the length of + the timeout. This value is checked whenever deadlock detection + is performed, so the accuracy of the timeout depends upon the + frequency of deadlock detection. + </p> + <p> + In general, when applications are not specifying lock and + transaction timeout values, the <a href="../api_reference/C/lockdetect.html#detect_DB_LOCK_DEFAULT" class="olink">DB_LOCK_DEFAULT</a> option is + probably the correct first choice, and other options should + only be selected based on evidence that they improve + transaction throughput. If an application has long-running + transactions, <a href="../api_reference/C/lockdetect.html#detect_DB_LOCK_YOUNGEST" class="olink">DB_LOCK_YOUNGEST</a> will guarantee that + transactions eventually complete, but it may do so at the + expense of a large number of lock request rejections (and + therefore, transaction aborts). + </p> + <p> + The alternative to using the <a href="../api_reference/C/envset_lk_detect.html" class="olink">DB_ENV->set_lk_detect()</a> method is to + explicitly perform deadlock detection using the Berkeley DB + <a href="../api_reference/C/lockdetect.html" class="olink">DB_ENV->lock_detect()</a> method. + </p> + <p> + The <a href="../api_reference/C/envset_lk_conflicts.html" class="olink">DB_ENV->set_lk_conflicts()</a> method allows you to specify your + own locking conflicts matrix. This is an advanced + configuration option, and is almost never necessary. + </p> </div> <div class="navfooter"> <hr /> @@ -76,13 +86,12 @@ and is almost never necessary.</p> <td width="40%" align="right"> <a accesskey="n" href="lock_max.html">Next</a></td> </tr> <tr> - <td width="40%" align="left" valign="top">Chapter 16. - The Locking Subsystem - </td> + <td width="40%" align="left" valign="top">Chapter 16. The Locking Subsystem </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> - <td width="40%" align="right" valign="top"> Configuring locking: sizing the system</td> + <td width="40%" align="right" valign="top"> Configuring locking: sizing the + system</td> </tr> </table> </div> |