参考：

x$bh
[B]uffer [H]eader

缓冲区头信息。通过连接x$bh和v$latch_children可以找到某个latch所保护的具体的block
select obj, dbarfil, dbablk from x$bh a, v$latch_children b where a.hladdr = b.addr

也可以找出同一个block在data buffer cache中存在多少个副本（多版本一致性读）
select dbarfil, dbablk, count(*) from x$bh group by dbarfil, dbablk having count(*) > 2

注意:x$bh.id=dba_objects.data_object_id而不是dba_objects.object_id

x$k2gte
[K]ernel [2]-phase commit [G]lobal [T]ransaction [E]ntry

x$k2gte.k2gtdses = v$session.saddr
x$k2gte.k2gtdxcb = v$transcation.addr

x$kcbwait
[K]ernel [C]ache [B]uffer [WAIT]

x$kcbfwait
[K]ernel [C]ache [B]lock [F]ile [WAIT]

select count, time, name from v$datafile df, x$kcbfwait fw where fw.indx+1 = df.file#

x$kcbwds
[K]ernel [C]ache [B]uffer [W]orking [D]ata [S]et

x$kcccf[K]ernel [C]ache [C]ontrolfile management [C]ontrol[F]ile

下面的SQL可以获得控制文件的block size
select cfnam, (cffsz+1)*cfbsz from x$kcccf. cfbsz

x$kcccp
[K]ernel [C]ache [C]ontrolfile [C]heckpoint [P]rogress

x$kccdi
[K]ernel [C]ache [C]ontrolfile management [D]atabase [i]nformation

x$kccle
[K]ernel [C]ache [C]ontrolfile [L]ogfile [S]tatistics

x$kcfio
[K]ernel [C]ache [F]ile [I]/[O]

x$kclfh
[K]ernel [C]ache [L]ock [F]ile [H]eader

x$kclfi
[K]ernel [C]ache [L]ock [F]ile [I]ndex

x$kcluh
[K]ernel [C]ache [L]ock [U]ndo [H]eader

x$kclui
[K]ernel [C]ache [L]ock [U]ndo [I]ndex

x$kcrfx
[K]ernel [c]ache [R]edo [F]ile [C]ontext

x$kdxst
[K]ernel [D]ata inde[X] [ST]atus

index_stats的基表

x$kdxhs
[K]ernel [D]ata inde[X] [H]i[S]togram

index_histogram的基表

x$kghlu
[K]ernel [G]eneric [H]eap [L]R[U]s

x$kglcursor
[K]ernel [G]eneric [L]ibrary cache [CURSOR]

v$sql和v$sqlarea的基表

x$kgllk
[K]ernel [G]eneric [L]ibrary cache [L]oc[K]

dba_kgllock的基表

x$kglob
[K]ernel [G]eneric [L]ibrary cache [OB]ject

x$kglob.kglhdadr = v$session_wait.p1raw

x$kglpn
[K]ernel [G]eneric [L]ibrary [P]i[N]

dba_kgllock的基表

x$kglst
[K]ernel [G]eneric [L]ibrary cache [ST]atus

x$kqfco
[K]ernel [Q]uery [F]ixed table [CO]lumns

x$kqfta
[K]ernel [Q]uery [F]ixed [TA]ble

x$kqfco.kqfcotab=x$kqfta.indx

x$kqfdt
[k]ernel [Q]uery [F]ixed [D]erived [T]able

x$kqfp
[K]ernel [Q]uery [F]ixed [P]rocudure

disk_and_fixed_objects的基表

x$kqfsz
[K]ernel [Q]uery [F]ixed [S]i[Z]e

x$kqfvi[K]ernel [Q]uery [F]ixed [VI]ew

x$kqfvt
[K]ernel [Q]uery [F]ixed [V]iew [T]able

x$fsled
[K]ernel [S]ervice [E]vent [D]efinition

x$kslei
[K]ernel [S]ervice [E]vent for [I]nstance

x$ksles
[K]ernel [S]ervice [E]vent for [S]ession

x$ksmfs
[K]ernel [S]ervice ]M]emory [F]ixed [S]GA

x$ksmfsv
[K]ernel [S]ervice ]M]emory [F]ixed [S]GA variables

x$ksmjs
[K]ernel [S]ervice ]M]emory [J]ava pool [S]ummary

x$ksmlru
[K]ernel [S]ervice ]M]emory [LRU]

访问该表会清空该表的内容

x$ksmls
[K]ernel [S]ervice ]M]emory [L]arge pool [S]ummary

x$ksmmem
[K]ernel [S]ervice [MEM]ory

整个SGA的内存映射。下面的SQL可以查询数据库的版本
select ksmmmval from x$ksmmem where indx = 2 （64位的oracle可能为1）

x$ksmpp
[K]ernel [S]ervice [M]emory [P]GA hea[P]

x$ksmsd
[K]ernel [S]ervice [M]emory [S]GA [D]efinition

x$ksmsp
[K]ernel [S]ervice [M]emory [S]GA] hea[P]

x$ksmspr
[K]ernel [S]ervice [M]emory [S]hared [P]ool [R]eserved

x$ksmss
[K]ernel [S]ervice [M]emory [S]hared pool [S]ummary

x$ksmup
[K]ernel [S]ervice [M]emory [U]GA hea[P]

x$ksppcv
[K]ernel [S]ervice [P]arameter [C]urrent] (session) [V]alue

x$ksppi
[K]ernel [S]ervice [P]arameter [P]arameter [I]nfo

v$parameter, v$system_parameter and v$system_parameter2的基表。通过关联x$ksppcv和x$ksppi可以查询隐含参数
select a.ksppinm Parameter, a.ksppdesc Description, b.ksppstvl "Session Value", c.ksppstvl "Instance Value"
from x$ksppi a, x$ksppcv b, x$ksppsv c
where a.indx = b.indx and a.indx = c.indx and a.ksppinm like '_%' escape '' order by 1

x$ksppsv
[K]ernel [S]ervice [P]arameter [S]ystem [V]alue

x$ksqeq
[K]ernel [S]ervice en[Q]ueue [E]n[Q]ueue

x$ksqrs
[K]ernel [S]ervice en[Q]ueue [RE]source

x$ksqst
[K]ernel [S]ervice en[Q]ueue [S]tatistics [T]ypes

x$ksulv
[K]ernel [S]ervice [U]ser [L]ocale [V]alue

x$ksulop
[K]ernel [S]ervice [U]ser [L]ong [OP]eration

x$ksupr
[K]ernel [S]ervice [U]ser [PR]ocess

x$ksuse
[K]ernel [S]ervice [U]ser [SE]ssion

x$ktcxb
[K]ernel [T]ransaction [C]ontrol object

v$transaction的基表

x$ktfbfe
[K]ernel [T]ransaction [F]ile [B]itmap [F]ree [E]xtent

LMT文件头的可用extent位图（相当于DMT的fet$）。dba_free_space的基表

x$ktfbhc
[K]ernel [T]ransaction [F]ile [B]itmap ??

每个datafile一条可用空间的记录

x$ktfbue
[K]ernel [T]ransaction [F]ile [B]itmap [U]sed [E]xtent

LMT文件头的已用extent位图（相当于DMT的uet$）

x$ktuxe
[K]ernel [T]ransaction [U]ndo transaction [E]ntry

9i之前，常用下面的语句获得当前SCN
select max(ktuxescnw * power(2, 32) + ktuxescnb) from x$ktuxe

x$kxfpsds
[K]ernel e[X]ecution [F]ast [P]rocess [S]lave [D]equeue [S]tatistics

x$kzsprv
[K]ernel security [S]ession [PR]i[V]ilege

v$enabledprivilege的基表（v$enabledprivilege是session_privs的基表）

x$kzsro
[K]ernel security [S]ession [RO]le

x$le
[L]ock [E]lement

select a.* from x$bh a, x$le b where a.le_addr = b.addr

x$le_stat
[L]ock [E]lement [STAT]us

x$message
(background process)[MESSAGE]s

x$trace
从9i开始，x$trace记录了跟踪事件的信息。下面的SQL显示了那些跟踪事件已经开启：
select event, count(*) from x$trace group by event

x$uganco
[U]ser [G]lobal [A]rea [N]etwork [CO]nnection

v$dblink的基表