oracle10g系统管理之REDO日志

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: small;"><span lang="EN-US"><span style="font-family: Times New Roman;">Redo</span></span><span style="">日志</span><span lang="EN-US"><span style="font-family: Times New Roman;">2</span></span></span></p>
<p class="MsoNormal" style=""><span style="font-family: Times New Roman;"><span style="" lang="EN-US"><span style=""><span style="font-size: small;">1.</span><span style='font: 7pt "Times New Roman";'> </span></span></span><span lang="EN-US"><span style="font-size: small;">SCN</span></span></span><span style="font-size: small;"><span style="">（</span><span lang="EN-US"><span style="font-family: Times New Roman;">SYSTEM CHANGE Number</span></span><span style="">）</span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt 21pt;"><span style="font-size: small;"><span lang="EN-US"><span style="font-family: Times New Roman;">SCN</span></span><span style="">是用于标示数据库变化的唯一标识号，其数值顺序递增。每当用户执行一次事务操作时，系统会为每次事务变化生成相应的</span><span lang="EN-US"><span style="font-family: Times New Roman;">SCN</span></span><span style="">。</span></span></p>
<p class="MsoNormal" style=""><span style="" lang="EN-US"><span style=""><span style="font-family: Times New Roman;"><span style="font-size: small;">2.</span><span style='font: 7pt "Times New Roman";'> </span></span></span></span><span style=""><span style="font-size: small;">日志序列号</span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt 21pt;"><span style=""><span style="font-size: small;">进行日志切换时，改值发生变化。</span></span></p>
<p class="MsoNormal" style=""><span style="" lang="EN-US"><span style=""><span style="font-family: Times New Roman;"><span style="font-size: small;">3.</span><span style='font: 7pt "Times New Roman";'> </span></span></span></span><span style=""><span style="font-size: small;">重做线程</span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt 21pt;"><span style="font-size: small;"><span style="">由一组相关的的重做日志组成。对于单例程数据库系统来说，只有一个重做线程，但是对于</span><span lang="EN-US"><span style="font-family: Times New Roman;">RAC</span></span><span style="">来说，多个例程会同时访问数据库。并且每个例程都有独立的重做线程。</span></span></p>