7.2.2.1 Buffer Cache Advisory StatisticsA number of statistics can be used to examine buffer cache activity. These include the following:V$DB_CACHE_ADVICEBuffer cache hit ratiobuffer cache 报告的统计统计的数据能被用于检查buffer cache的活动。7.2.2.2 Using V$DB_CACHE_ADVICEThis view is ...【阅读全文】
前面说过一个SQL语句如果进行引发排序的操作,通常会进行全部范围扫描。如下面的SQL语句:Select * from product where item_cd like ‘AB%’ and category like ‘C%’order by item_cd desc; 由于存在排序操作,因此无法进行局部范围扫描。但是我们知道,如果在字段item_cd上建立有索引的话,那么就可以...【阅读全文】