1.oracle11g查看自动收集统计信息是否开启
SQL> select client_name,status from dba_autotask_client; CLIENT_NAME Status ---------------------------------------------------------------- -------- auto optimizer stats collection ENABLED
https://blog.csdn.net/xqzhang8/article/details/72758208
2.手动分析某张表
exec dbms_stats.gather_table_ststs('ownname','tabname');
DBMS_STATS.GATHER_TABLE_STATS ( ownname VARCHAR2, tabname VARCHAR2, partname VARCHAR2, estimate_percent NUMBER, block_sample BOOLEAN, method_opt VARCHAR2, degree NUMBER, granularity VARCHAR2, cascade BOOLEAN, stattab VARCHAR2, statid VARCHAR2, statown VARCHAR2, no_invalidate BOOLEAN, force BOOLEAN); 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(默认值为FOR ALL COLUMNS SIZE AUTO): 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histograms for columns <list> SIZE <N> | REPEAT | AUTO | SKEWONLY:统计指定列的histograms.N的取值范围[1,254]; REPEAT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 thedata degree:决定并行度.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FALSE. 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)
3.对象统计信息锁定的解决办法（ORA-20005/ORA-38029）
解锁单个对象
先查出被锁定的表select table_name from user_tab_statistics where stattype_locked is not null;
然后再解锁对象
exec dbms_stats.unlock_table_stats(user,'表名');
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