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分类: Oracle

2012-12-05 17:33:12

参考col_usage$中的predicate columns记录:

 

Cksxm.c

Monitor Modification Hash Table Base

modification hash table entry

modification hash table chunk

monitoring column usage element

ksxmlock_1

lock table sys.col_usage$ in exclusive mode

lock table sys.col_usage$ in exclusive mode nowait

 

update sys.col_usage$

   set equality_preds    = equality_preds +

                           decode(bitand(:flag, 1), 0, 0, 1),

       equijoin_preds    = equijoin_preds +

                           decode(bitand(:flag, 2), 0, 0, 1),

       nonequijoin_preds = nonequijoin_preds +

                           decode(bitand(:flag, 4), 0, 0, 1),

       range_preds       = range_preds + decode(bitand(:flag, 8), 0, 0, 1),

       like_preds        = like_preds + decode(bitand(:flag, 16), 0, 0, 1),

       null_preds        = null_preds + decode(bitand(:flag, 32), 0, 0, 1),

       timestamp         = :time

 where obj# = :ob jn

   and intcol# = :coln

 

insert into sys.col_usage$

  (obj#,

   intcol#,

   equality_preds,

   equijoin_preds,

   nonequijoin_preds,

   range_preds,

   like_preds,

   null_preds,

   timestamp)

values

  (:objn,

   :coln,

   decode(bitand(:flag, 1), 0, 0, 1),

   decode(bitand(:flag, 2), 0, 0, 1),

   decode(bitand(:flag, 4), 0, 0, 1),

   decode(bitand(:flag, 8), 0, 0, 1),

   decode(bitand(:flag, 16), 0, 0, 1),

   decode(bitand(:flag, 32), 0, 0, 1),

   :time)

 

使用dbms_stats的’SIZE AUTO’模式收集表上的统计信息会首先参考col_usage$中的predicate columns记录:

SQL> begin

  2

  3    dbms_stats.gather_table_stats(ownname    => 'SYS',

  4                                  tabname    => 'MACLEAN',

  5                                  method_opt => 'FOR ALL COLUMNS SIZE AUTO');

  6  end;

  7  /

 

PL/SQL procedure successfully completed.

 

============10046 level 12 trace content======================

SELECT /*+ ordered use_nl(o c cu h) index(u i_user1) index(o i_obj2)

               index(ci_obj#) index(cu i_col_usage$)

               index(h i_hh_obj#_intcol#) */

 C.NAME COL_NAME,

 C.TYPE# COL_TYPE,

 C.CHARSETFORM COL_CSF,

 C.DEFAULT$ COL_DEF,

 C.NULL$ COL_NULL,

 C.PROPERTY COL_PROP,

 C.COL # COL_UNUM,

 C.INTCOL# COL_INUM,

 C.OBJ# COL_OBJ,

 C.SCALE COL_SCALE,

 H.BUCKET_CNT H_BCNT,

 (T.ROWCNT - H.NULL_CNT) / GREATEST(H.DISTCNT, 1) H_PFREQ,

 C.LENGTH COL_LEN,

 CU.TIMES TAMP CU_TIME,

 CU.EQUALITY_PREDS CU_EP,

 CU.EQUIJOIN_PREDS CU_EJP,

 CU.RANGE_PREDS CU_RP,

 CU.LIKE_PREDS CU_LP,

 CU.NONEQUIJOIN_PREDS CU_NEJP,

 CU.NULL_PREDS NP

  FROM SYS.USE        R$ U,

       SYS.OBJ$       O,

       SYS.TAB$       T,

       SYS.COL$       C,

       SYS.COL_USAGE$ CU,

       SYS.HIST_HEAD$ H

 WHERE :B3 = '0'

   AND U.NAME = :B2

   AND O.OWNER# = U.USER#

   AND O.TYPE# = 2

   AND O.NAME = :B1

   AND O.OBJ# = T.OBJ#

   AND O.OBJ# = C.OBJ#

   AND C.OBJ# = CU.OBJ#(+)

   AND C.INTCOL# = CU.INTCOL#(+)

   AND C.OBJ# = H.OBJ#(+)

   AND C.INTCOL# = H.INTCOL#(+)

UNION ALL

SELECT /*+

ordered use_nl(c) */

 C.KQFCONAM COL_NAME,

 C.KQFCODTY COL_TYPE,

 DECODE(C.KQFCODTY, 1, 1, 0) COL_CSF,

 NULL COL_DEF,

 0 COL_NULL,

 0 COL_PROP,

 C.KQFCOCNO COL_UNUM,

 C.KQFCOC NO COL_INUM,

 O.KQFTAOBJ COL_OBJ,

 DECODE(C.KQFCODTY, 2, -127, 0) COL_SCALE,

 H.BUCKET_CNT H_BCNT,

 (ST.ROWCNT - NULL_CNT) / GREATEST(H.DISTCNT, 1) H_PFREQ,

 DECODE(C.KQFCODTY, 2, 22, C.KQFCOSIZ) COL_LEN,

 CU.TIMESTAMP CU_TIME,

 CU.EQUALITY_PREDS CU_EP,

 CU.EQUIJOIN_PREDS CU_EJP,

 CU.RANGE_PREDS CU_RP,

 CU.LIKE_PREDS CU_LP,

 CU.NONEQUIJOIN_PREDS CU _NEJP,

 CU.NULL_PREDS NP

  FROM SYS.X$KQFTA    O,

       SYS.TAB_STATS$ ST,

       SYS.X$KQFCO    C,

       SYS.COL_USAGE$ CU,

       SYS.HIST_HEAD$ H

 WHERE :B3 != '0'

   AND :B2 = 'SYS'

   AND O.KQFTANAM = :B1

   AND O.KQFTAOBJ = ST.OBJ#(+)

   AND O.KQFTAOBJ = C.KQFCOTOB

   AND C.KQFCOTOB = CU.OBJ#(+)

   AND C.KQFCOCNO = CU.INTCOL#(+)

   AND C.KQFCOTOB = H.OBJ#(+)

   AND C.KQFCOCNO = H.INTCO L#(+) oracle培训http://www.cuug.com/

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