查看底层表从v_$parameter说起

1.首先来看一段代码

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 and
  x.ksppinm like '%_&par%'
order by
  translate(x.ksppinm, ' _', ' ')
/

2.问题

a.别人是怎么知道这个答案的？如果是你现在能按哪种方式获取？

3.

a.采用10046跟踪

eg.select count(name) from sys.v_$parameter;

STAT #7 id=2 cnt=258 pid=1 pos=1 obj=0 op='HASH JOIN  (cr=0 pr=0 pw=0 time=12104
us)'
STAT #7 id=3 cnt=1379 pid=2 pos=1 obj=0 op='FIXED TABLE FULL X$KSPPI (cr=0 pr=0 p
w=0 time=4151 us)'
STAT #7 id=4 cnt=1385 pid=2 pos=2 obj=0 op='FIXED TABLE FULL X$KSPPCV (cr=0 pr=0
pw=0 time=1391 us)'

b.将select语句拷到PL/SQL DEVELOPER，按F5后从执行计划中可查看到

c.sqlplus中采用

explain plan for sql_statement;

select * from table(dbms_xplan.display());

4.如何得知X$KSPPI和X$KSPPCV字段的意思？