Oracle 12C R2-新特性-跟踪索引使用情况V$INDEX_USAGE_INFO

12.2中新增了新的视图V$INDEX_USAGE_INFO，提供索引在数据库中使用的情况。从而可以看出索引是否被使用以及使用率。这些信息有助于评估索引的策略。

SQL> desc V$INDEX_USAGE_INFO
 Name	   Null?    Type
 ----------------------------------------- -------- ----------------------------
 INDEX_STATS_ENABLED	    NUMBER
 INDEX_STATS_COLLECTION_TYPE	    NUMBER
 ACTIVE_ELEM_COUNT	    NUMBER
 ALLOC_ELEM_COUNT	    NUMBER
 MAX_ELEM_COUNT     NUMBER
 FLUSH_COUNT	    NUMBER
 TOTAL_FLUSH_DURATION	    NUMBER
 LAST_FLUSH_TIME	    TIMESTAMP(3)
 STATUS_MSG	    VARCHAR2(256)
 CON_ID     NUMBER
 
SQL> select INDEX_STATS_ENABLED,ACTIVE_ELEM_COUNT,CON_ID FROM V$INDEX_USAGE_INFO;
INDEX_STATS_ENABLED   ACTIVE_ELEM_COUNT	  CON_ID

------------------- ----------------- ----------
  1	    0	       1

NDEX_STATS_ENABLED：0: Index statistics are disabled 1: Index statistics are enabled
更多信息参考官方文档：
http://docs.oracle.com/database/122/REFRN/V-INDEX_USAGE_INFO.htm#REFRN-GUID-247622FE-A377-4DD3-BD93-067407D68AE0