oracle 查看隐含参数
v$parameter视图中查询参数的时候其实都是通过x$ksppi和x$ksppcv这两个内部视图中得到的。
可以通过如下方式查询当前实例的所有隐含参数：
select
x.ksppinm name,
y.ksppstvl value,
y.ksppstdf isdefault,
decode(bitand(y.ksppstvf,7),1,'MODIFIED',4,'SYSTEM_MOD','FALSE') ismod,
decode(bitand(y.ksppstvf,2),2,'TRUE','FALSE') isadj
from
sys.x$ksppi x,
sys.x$ksppcv y
where
x.inst_id = userenv('Instance') and
y.inst_id = userenv('Instance') and
x.indx = y.indx
order by
translate(x.ksppinm, ' _', ' ')
/
修改隐含参数的方法：alter system set "_cursor_bind_capture_interval"=5 （记得加引号）
-----下面部分给出了如何知道隐含参数查询的方法-------
我们在查看内存参数时会看到如下执行计划：
SQL> set autotrace traceonly
SQL> select * from v$parameter;
342 rows selected.
Execution Plan
----------------------------------------------------------
Plan hash value: 1128103955
------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 4414 | 1 (100)| 00:00:01 |
|* 1 | HASH JOIN | | 1 | 4414 | 1 (100)| 00:00:01 |
|* 2 | FIXED TABLE FULL| X$KSPPI | 1 | 249 | 0 (0)| 00:00:01 |
| 3 | FIXED TABLE FULL| X$KSPPCV | 100 | 406K| 0 (0)| 00:00:01 |
------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - access("X"."INDX"="Y"."INDX")
filter(TRANSLATE("KSPPINM",'_','#') NOT LIKE '#%' OR
"KSPPSTDF"='FALSE' OR BITAND("KSPPSTVF",5)>0)
2 - filter("X"."INST_ID"=USERENV('INSTANCE') AND
BITAND("KSPPIFLG",268435456)=0 AND TRANSLATE("KSPPINM",'_','#') NOT
LIKE '##%')
Statistics
----------------------------------------------------------
64 recursive calls
0 db block gets
6 consistent gets
0 physical reads
0 redo size
35905 bytes sent via SQL*Net to client
661 bytes received via SQL*Net from client
24 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
342 rows processed
SQL> desc x$ksppi;
Name Null? Type
----------------------------------------------------- -------- ------------------------------------
ADDR RAW(4)
INDX NUMBER
INST_ID NUMBER
KSPPINM VARCHAR2(80)
KSPPITY NUMBER
KSPPDESC VARCHAR2(255)
KSPPIFLG NUMBER
KSPPILRMFLG NUMBER
KSPPIHASH NUMBER
SQL> desc x$ksppcv
Name Null? Type
----------------------------------------------------- -------- ------------------------------------
ADDR RAW(4)
INDX NUMBER
INST_ID NUMBER
KSPPSTVL VARCHAR2(4000)
KSPPSTDVL VARCHAR2(4000)
KSPPSTDF VARCHAR2(9)
KSPPSTVF NUMBER
KSPPSTCMNT VARCHAR2(255)
由此可见，可以通过下面方法查询所有隐含参数
select
x.ksppinm name,
y.ksppstvl value,
y.ksppstdf isdefault,
decode(bitand(y.ksppstvf,7),1,'MODIFIED',4,'SYSTEM_MOD','FALSE') ismod,
decode(bitand(y.ksppstvf,2),2,'TRUE','FALSE') isadj
from
sys.x$ksppi x,
sys.x$ksppcv y
where
x.inst_id = userenv('Instance') and
y.inst_id = userenv('Instance') and
x.indx = y.indx
order by
translate(x.ksppinm, ' _', ' ')
/