分析索引

－－分析索引

analyze table th compute statistics for table for all indexes for all indexed columns;
analyze table th compute statistics for table for all indexes ;
analyze table th compute statistics for table for indexed columns;

SQL> analyze table th compute statistics;

－－

alter system flush shared_pool;

--删除统计信息
select 'analyze table ' || table_name || ' delete statistics;' from user_tables;
analyze table  table_name delete statistics;