您的位置:首页 > 数据库 > Oracle

7.Oracle杂记——数据字典dba_indexes

2017-10-27 21:35 429 查看
7.Oracle杂记——数据字典dba_indexes
视图dba_indexes是关于数据库中所有索引的描述。

查看视图结构如下:

sys@PDB1> desc dba_indexes;

 Name                                                                                                     Null?         Type

 ------------------------------------------------------------- ------------------------------------

 OWNER                                                                                                                   NOT NULL VARCHAR2(128)

 INDEX_NAME                                                                                     NOT NULL VARCHAR2(128)

 INDEX_TYPE                                                                                                                     VARCHAR2(27)

 TABLE_OWNER                                                                                  NOT NULL VARCHAR2(128)

 TABLE_NAME                                                                                     NOT NULL VARCHAR2(128)

 TABLE_TYPE                                                                                                                     VARCHAR2(11)

 UNIQUENESS                                                                                                                   VARCHAR2(9)

 COMPRESSION                                                                                                               VARCHAR2(13)

 PREFIX_LENGTH                                                                                                             NUMBER

 TABLESPACE_NAME                                                                                                     VARCHAR2(30)

 INI_TRANS                                                                                                                        NUMBER

 MAX_TRANS                                                                                                                    NUMBER

 INITIAL_EXTENT                                                                                                           NUMBER

 NEXT_EXTENT                                                                                                                 NUMBER

 MIN_EXTENTS                                                                                                                NUMBER

 MAX_EXTENTS                                                                                                               NUMBER

 PCT_INCREASE                                                                                                                NUMBER

 PCT_THRESHOLD                                                                                                                             NUMBER

 INCLUDE_COLUMN                                                                                                      NUMBER

 FREELISTS                                                                                                                         NUMBER

 FREELIST_GROUPS                                                                                                        NUMBER

 PCT_FREE                                                                                                                          NUMBER

 LOGGING                                                                                                                           VARCHAR2(3)

 BLEVEL                                                                                                                              NUMBER

 LEAF_BLOCKS                                                                                                                  NUMBER

 DISTINCT_KEYS                                                                                                              NUMBER

 AVG_LEAF_BLOCKS_PER_KEY                                                                                  NUMBER

 AVG_DATA_BLOCKS_PER_KEY                                                                                 NUMBER

 CLUSTERING_FACTOR                                                                                                  NUMBER

 STATUS                                                                                                                            VARCHAR2(8)

 NUM_ROWS                                                                                                                    NUMBER

 SAMPLE_SIZE                                                                                                                 NUMBER

 LAST_ANALYZED                                                                                                                              DATE

 DEGREE                                                                                                                            VARCHAR2(40)

 INSTANCES                                                                                                                       VARCHAR2(40)

 PARTITIONED                                                                                                                  VARCHAR2(3)

 TEMPORARY                                                                                                                    VARCHAR2(1)

 GENERATED                                                                                                                     VARCHAR2(1)

 SECONDARY                                                                                                                     VARCHAR2(1)

 BUFFER_POOL                                                                                                                VARCHAR2(7)

 FLASH_CACHE                                                                                                                 VARCHAR2(7)

 CELL_FLASH_CACHE                                                                                                     VARCHAR2(7)

 USER_STATS                                                                                                                    VARCHAR2(3)

 DURATION                                                                                                                        VARCHAR2(15)

 PCT_DIRECT_ACCESS                                                                                                   NUMBER

 ITYP_OWNER                                                                                                                  VARCHAR2(128)

 ITYP_NAME                                                                                                                     VARCHAR2(128)

 PARAMETERS                                                                                                                  VARCHAR2(1000)

 GLOBAL_STATS                                                                                                              VARCHAR2(3)

 DOMIDX_STATUS                                                                                                                           VARCHAR2(12)

 DOMIDX_OPSTATUS                                                                                                   VARCHAR2(6)

 FUNCIDX_STATUS                                                                                                        VARCHAR2(8)

 JOIN_INDEX                                                                                                                     VARCHAR2(3)

 IOT_REDUNDANT_PKEY_ELIM                                                                                 VARCHAR2(3)

 DROPPED                                                                                                                          VARCHAR2(3)

 VISIBILITY                                                                                                                         VARCHAR2(9)

 DOMIDX_MANAGEMENT                                                                                                            VARCHAR2(14)

 SEGMENT_CREATED                                                                                                    VARCHAR2(3)

 ORPHANED_ENTRIES                                                                                                   VARCHAR2(3)

 INDEXING                                                                                                                          VARCHAR2(7)

因为索引包含很多属性,所以有很多的列,当然用的时候不一定需要使用所有的属性。但是如果我们此处搞明白所有列的含义,对后续的理解也是很有帮助的,那么蛤蟆来一一说明,如果有误欢迎大家指正,具体参考《reference.pdf》:

OWNER:索引拥有者。

 INDEX_NAME:索引名字

 INDEX_TYPE:索引类型(例如B树-NORMAL,位图之类 BITMAP,簇类 CLUSTER等)

 TABLE_OWNER:索引对象的拥有者

 TABLE_NAME:索引对象的名字

 TABLE_TYPE:索引对象的类型(VIEW,TABLE,CLUSTER,SYNONYM,SEQUENCE,NEXT OBJECT等)

 UNIQUENESS       : 是否唯一

 COMPRESSION:是否压缩(ENABLED,DISABLED,ADVANCED)

 PREFIX_LENGTH:压缩键上前缀的列数量

 TABLESPACE_NAME:包含索引的表空间名字。

 INI_TRANS:事务表的初始大小由对象的INITRANS设置指定。默认是2(12C)

 MAX_TRANS        :最大的MAXTRANS条目,默认是255(12C)

 INITIAL_EXTENT:初始化区大小65536

 NEXT_EXTENT:第二个区大小1048576

 MIN_EXTENTS:段中允许的最小区大小

 MAX_EXTENTS:段中允许的最大区大小(默认2G)

 PCT_INCREASE:后面的区是前面区的增长百分比,50%,表示每个后续区间比前面的大50%。

 PCT_THRESHOLD:每个块中允许索引入口的百分比阈值

 INCLUDE_COLUMN :索引组织表主键索引中包含最后一列的列ID。

 FREELISTS:分配到这个段的进程自由列表数量。

 FREELIST_GROUPS:分配到这个段的自由列表组的数量

 PCT_FREE: 一个块中最小自由空间的百分比

 LOGGING: 索引改变是否记录到日志

 BLEVEL:B树索引等级(从根块到叶子块的深度,如果是0,说明根块和叶子块是同一个)

 LEAF_BLOCKS:索引中叶子块的数量。

 DISTINCT_KEYS:不同索引值的数量。

 AVG_LEAF_BLOCKS_PER_KEY:索引中的每个值平均在多少个叶子块中。如果是唯一和主键那么这个值恒等于1。

 AVG_DATA_BLOCKS_PER_KEY:通过索引中的一个值指向表中数据块,该数据块数量的平均值。

 CLUSTERING_FACTOR:聚集因子,表示表中行基于索引排列程度。聚集因子越接近块,那么表中很好的排序了。这种情况下,在一个叶子快中的的索引都指向同一个数据块。

 STATUS :表示一个未分区的索引是合法的还是不可用的。

 NUM_ROWS        :索引的行数量。

 SAMPLE_SIZE     :分析索引的参样大小(应该可以用此来判断统计数据)

 LAST_ANALYZED:最近索引分析的日期。

 DEGREE :每个实例扫描索引的线程数。

 INSTANCES:索引被多少实例扫描

 PARTITIONED      :索引是否分区

 TEMPORARY        :索引是否在临时表中

 GENERATED:索引名字是否是系统产生的

 SECONDARY         :索引是否通过ODCIIndexCreate方法创建的

 BUFFER_POOL:用于索引块的缓冲池(DEFAULT,KEEP,RECYCLE,NULL)

 FLASH_CACHE:数据库Smart Flash Cache的hint用于索引块

 CELL_FLASH_CACHE: Cell flash cache 的hint 用于索引块

 USER_STATS:静态统计是否直接被用户使用

 DURATION:临时表空间的持续时间(如果索引建立在临时表空间上的话)

 PCT_DIRECT_ACCESS:对于索引组织表上的secondaryinidex,行百分比的合理猜测

 ITYP_OWNER      :对于域索引,索引类型的拥有者

 ITYP_NAME:对于域索引,索引类型名字

 PARAMETERS      :对于域索引,参数字符串

 GLOBAL_STATS:索引的统计是否收集了

 DOMIDX_STATUS:域索引的状态。

 DOMIDX_OPSTATUS:域索引的操作状态

 FUNCIDX_STATUS:基于函数索引的状态

 JOIN_INDEX:索引是否是结合的

 IOT_REDUNDANT_PKEY_ELIM:在索引组织表中,冗余的主键列是否从从索引中删除

 DROPPED:索引是否已经被删除了,并在recycle中

 VISIBILITY:索引是否可见

 DOMIDX_MANAGEMENT:如果是域索引,主索引是系统管理还是用户管理

 SEGMENT_CREATED:索引段是否已经创建

 ORPHANED_ENTRIES:全局索引是否包含陈旧的入口(因为DROP/TRUNCATEPARTITION, or MODIFY PARTITION INDEXING OFF等操作

 INDEXING:全局索引是否和表解耦。PARTIAL(索引是部分的),FULL(索引会包含表的所有分区)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
内容来自用户分享和网络整理,不保证内容的准确性,如有侵权内容,可联系管理员处理 点击这里给我发消息
标签: