Oracle 收集统计值 收集统计信息

--收集Oracle统计信息BEGIN  DBMS_STATS.GATHER_TABLE_STATS(OWNNAME          => 'OWNER_NAME',  --数据库用户名                                TABNAME          => 'TABLE_NAME',  --表名                                PARTNAME         => 'PARTITION_NAME',  --分区名                                ESTIMATE_PERCENT => DBMS_STATS.AUTO_SAMPLE_SIZE,                                METHOD_OPT       => 'for all columns size repeat',                                DEGREE           => DBMS_STATS.AUTO_DEGREE,                                CASCADE          => TRUE);END;--查询表的统计信息SELECT *  FROM DBA_TAB_STATISTICS S WHERE S.OWNER = 'OWNER_NAME'   --数据库用户名   AND S.TABLE_NAME = 'TABLE_NAME'  --表名 ORDER BY S.LAST_ANALYZED DESC;--Oracle统计信息DBMS_STATS.gather_table_stats    (ownname varchar2,     tabname varchar2,     partname varchar2 default null,     estimate_percent number default   to_estimate_percent_type(get_param('ESTIMATE_PERCENT')),     block_sample boolean default FALSE,     method_opt varchar2 default get_param('METHOD_OPT'),     degree number default to_degree_type(get_param('DEGREE')),     granularity varchar2 default get_param('GRANULARITY'),     cascade boolean default to_cascade_type(get_param('CASCADE')),     stattab varchar2 default null, statid varchar2 default null,     statown varchar2 default null,     no_invalidate boolean default to_no_invalidate_type(get_param('NO_INVALIDATE')),     stattype varchar2 default 'DATA',     force boolean default FALSE);/*参数说明:ownname:   要分析表的拥有者tabname:   要分析的表名.partname: 分区的名字,只对分区表或分区索引有用.estimate_percent:采样行的百分比,取值范围[0.000001,100],null为全部分析,不采样. 常量:DBMS_STATS.AUTO_SAMPLE_SIZE是默认值,由oracle决定最佳取采样值.block_sapmple:是否用块采样代替行采样.method_opt:    决定histograms信息是怎样被统计的.method_opt的取值如下:for all columns:统计所有列的histograms.for all indexed columns:统计所有indexed列的histograms.for all hidden columns:统计你看不到列的histogramsfor columns <list> SIZE <N> | REPEAT | AUTO | SKEWONLY:                                              统计指定列的histograms.N的取值范围[1,254]; R                                              EPEAT上次统计过的histograms;                                              AUTO由oracle决定N的大小;                                              SKEWONLY multiple end-points with the same value which is what we define by "                                                         there is skew in the datadegree:              设置收集统计信息的并行度.默认值为null.granularity:Granularity of statistics to collect ,only pertinent if the table is partitioned.cascade:       是收集索引的信息.默认为falase.stattab        指定要存储统计信息的表,statid如果多个表的统计信息存储在同一个stattab中用于进行区分.statown存储统计信息表的拥有者.以上三个参数若不指定,                     统计信息会直接更新到数据字典.no_invalidate: Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors                         immediately if set to FALSE.force:         即使表锁住了也收集统计信息*/--例子:execute dbms_stats.gather_table_stats(ownname => 'owner',                                      tabname => 'table_name' ,                                      estimate_percent => null ,                                      method_opt => 'for all indexed columns' ,                                      cascade => true);--GATHER_INDEX_STATS--==========================BEGINSYS.DBMS_STATS.GATHER_INDEX_STATS (OwnName => 'ABC',                                   IndName => 'IDX_FUNC_ABC',                                   Estimate_Percent => 10,                                   Degree => SYS.DBMS_STATS.DEFAULT_DEGREE,                                   No_Invalidate => FALSE);END;