dba_free_space视图访问变慢、消耗变高解决办法

郑全

在11g数据库版本，随着数据库的使用，垃圾数据的积累，访问dba_free_space视图的消耗会越来越高，访问耗时越来越长

建议采取以下措施，优化dba_free_space视图的访问效率

1、重建dba_free_space视图

create or replace view DBA_FREE_SPACE
    (TABLESPACE_NAME, FILE_ID, BLOCK_ID,
     BYTES, BLOCKS, RELATIVE_FNO)
as
select ts.name, fi.file#, f.block#,
       f.length * ts.blocksize, f.length, f.file#
from sys.ts$ ts, sys.fet$ f, sys.file$ fi
where ts.ts# = f.ts#
  and f.ts# = fi.ts#
  and f.file# = fi.relfile#
  and ts.bitmapped = 0
union all
select /*+ ordered use_nl(f) use_nl(fi) */
       ts.name, fi.file#, f.ktfbfebno,
       f.ktfbfeblks * ts.blocksize, f.ktfbfeblks, f.ktfbfefno
from sys.ts$ ts, sys.x$ktfbfe f, sys.file$ fi
where ts.ts# = f.ktfbfetsn
  and f.ktfbfetsn = fi.ts#
  and f.ktfbfefno = fi.relfile#
  and ts.bitmapped <> 0 and ts.online$ in (1,4) and ts.contents$ = 0
union all
select /*+ ordered use_nl(u) use_nl(fi) */
       ts.name, fi.file#, u.ktfbuebno,
       u.ktfbueblks * ts.blocksize, u.ktfbueblks, u.ktfbuefno
from sys.recyclebin$ rb, sys.ts$ ts, sys.x$ktfbue u, sys.file$ fi
where ts.ts# = rb.ts#
  and rb.ts# = fi.ts#
  and u.ktfbuefno = fi.relfile#
  and u.ktfbuesegtsn = rb.ts#
  and u.ktfbuesegfno = rb.file#
  and u.ktfbuesegbno = rb.block#
  and ts.bitmapped <> 0 and ts.online$ in (1,4) and ts.contents$ = 0
union all
select ts.name, fi.file#, u.block#,
       u.length * ts.blocksize, u.length, u.file#
from sys.ts$ ts, sys.uet$ u, sys.file$ fi, sys.recyclebin$ rb
where ts.ts# = u.ts#
  and u.ts# = fi.ts#
  and u.segfile# = fi.relfile#
  and u.ts# = rb.ts#
  and u.segfile# = rb.file#
  and u.segblock# = rb.block#
  and ts.bitmapped = 0
/


2、清空数据库回收站

sqlplus / as sysdba
purge dba_recyclebin;

说明：在11.2.0.4上测试有效