Oracle X$ View:X$KJBL

The status of buffer locks can be checked through the table X$KJBL; it is not necessary to dump the locks with
the ORADEBUG command, in order to get to this information. The table contains the client and shadow locks.

 

 

Column name            Data type            Description
KJBLLOCKP              RAW,kjbl*            Lock pointer. Can be joined with X$LE.LE_KJBL.
KJBLGRANT              VARCHAR2 (9)         Current grant level, valid values are:
                                            KJUSERNL (0), KJUSERCR (1), KJUSERCW (2), KJUSERPR
                                            (3), KJUSERPW (4), KJUSEREX (5)
KJBLREQUEST            VARCHAR2 (9)         Request Level, valid values are:
                                            (See KJBLGRANT)
                                            KJBLROLE NUMBER Granted Role:
                                            KJBL_GRANT_N (0x00), KJBL_GRANT_S (0x01)
                                            KJBL_GRANT_X (0x02), KJBL_REQ_S (0x04),
                                            KJBL_REQ_X (0x08), KJBL_REQ_STL (0x10),
                                            KJBL_REQ_CR (0x10), KJBL_OACK (0x20),
                                            KJBL_ROLE_G (0x40), KJBL_HAS_PI (0x80)
                                            
KJBLRESP               RAW, kjbr*          Current Resource Info (Resource pointer)
KJBLNAME               VARCHAR2 (30)       Resource name in Hex notation ([id1], [id2], [Type])
KJBLNAME2              VARCHAR2 (30)       Resource name in Decimal notation (id1, id2, Type)
KJBLQUEUE              NUMBER              Grant / Convert queue:
                                           Grant Queue (0x00), Convert Queue 0x80
KJBLLOCKST             VARCHAR2 (64)       Lock state:
                                           KJUSERGRANTED (0x00), KJUSEROPENING (0x01),
                                           KJUSERCLOSING (0x02), KJUSERCANCELLING (0x04),
                                           KJUSERCVTING (0x08), KJUSERSTANDALONE (0x10),
                                           KJUSERASTDELAYED (0x20), KJUSERMSGPENDING(0x40),
                                           KJUSERFROZEN (0x80)
KJBLWRITING            NUMBER              Writing
                                           ·0, not writing; 1, writing
KJBLREQWRITE                               Write requested
                                           ·  0, no request; 1, write requested
KJBLOWNER              NUMBER              Owning instance – node id
KJBLMASTER             NUMBER              Master instance – node id
KJBLBLOCKED            NUMBER              Blocked lock? – Checks if there is a converting lock
KJBLBLOCKER            NUMBER              Blocking lock? - Checks if there is a lock held in an incompatible mode

 

 

The columns KJBLBLOCKER and KJBLBLOCKED in particular let you determine if you are waiting on
blocked lock or if you are blocking other sessions. With this table, it is also possible to determine where the
lock is mastered and the role of the lock.

Oracle X$ View:X$KJMSDP

X$KJMSDP

The table X$KJMSDP has entries for each LMS process that is configured for the instance. The default
number of LMS processes is the number of CPU’s divided by 4, but 2 as a minimum. The LMS processes are
responsible for the delivery of the GCS messages and blocks to the other instances.

 

 

Column name          Data Type               Description
ADDR                 RAW(4)                  Identifier / Address
INDX                 NUMBER                  LMS id (starts with 0)
INST_ID              NUMBER                  Instance id
PID                  NUMBER                  LMS process id (starts with 0)
FLAG                 NUMBER                  Flags:
ACTUAL_RCV           NUMBER                  Actual Global Cache Service messages received
LOGICAL_RCV          NUMBER                  Logical Global Cache Service messages received
LOGICAL_PTIME        NUMBER                  Logical Global Cache Service messages process time (ms)
SBUF_TIME            NUMBER                  Time for flushing send buffer (ms)
FC_SENT              NUMBER                  Number of flow control messages sent
NULL_REQ             NUMBER                  Number of null requests send by this process
WAIT_TICKET          NUMBER                  Number of times waited for tickets
CRB_SENT             NUMBER                  Number of CR blocks sent
CRB_STIME            NUMBER                  CR block sent time (ms)
RCVQ_TIME            NUMBER                  Receive message queue time
ERRCHK_TIME          NUMBER                  Error check time
FMSGBUFS_TIME        NUMBER                  Flush message buffer time
RCFGFRZ_TIME         NUMBER                  Reconfiguration freeze time
RCFGSYNC_TIME        NUMBER                  Reconfiguration sync time
PBATFLUSH_TIME       NUMBER                  Process batch flush time
SQFLUSH_TIME         NUMBER                  Send queue flush time
DRMSYNC_TIME         NUMBER                  DRM sync time
RCVMSG_TIME          NUMBER                  Time to receive messages
BPMSG_TIME           NUMBER                  Batch message process time
PMSG_TIME            NUMBER                  Time to process message from receiver
SCANQ_TIME           NUMBER                  Scan queue time
PDCQ_TIME            NUMBER                  Time to check down-convert queue
PTOQ_TIME            NUMBER                  Time to check deferred ping queue
FSCH_TIME            NUMBER                  Time to flush the side-channel messages
IPBAT_TIME           NUMBER                  Time for embedded batch message processing
RETRYQ_TIME          NUMBER                  Retry queue time

 

 

X$KJMSDP
As with the LMD process, it is important to check if there are waits for tickets. If this occurs, look at the
corresponding section at the description of the table X$KJMDDP for further explanation.

Know more about LOCK_SGA Parameter

Can you kindly define and explain of  lock_sga  parameter?each flatform(HP, IBM, SUN) recommended value of both parameter
and why it is recommended like that value.

 

LOCK_SGA locks the entire SGA into physical memory. It is usually advisable to lock the SGA into real (physical) memory, especially if the use of virtual memory would include storing some of the SGA using disk space. This parameter is ignored on platforms that do not support it.

Each platform has its own recommendations and support over the parameter value. Hence you would see differences in the recommendations.

+ lock_sga Only locks the entire SGA into physical memory.

+ It can be set to TRUE as long as you want to lock the entire SGA in the physical memeory and your OS supports it. As for as i know it works in all the platforms.

LOCK_SGA locks the entire SGA into physical memory. It is usually advisable to lock the SGA into real (physical) memory, especially if the use of virtual memory would include storing some of the SGA using disk space.

NOTE:: This parameter is ignored on platforms that do not support it.

+ Windows For sure doesn’t support this parameter.

+ AIX Supports it.

+ LOCK_SGA is not supported on Solaris.

+ On Hp-UX if you have mlock (OS privilege) then LOCK_SGA is not required

+ Linux also supports this parameter

You can also review

Note 577898.1 – ORA-27102 Received At Startup When LOCK_SGA Is Set Although Enough Memory Is Available.

 

lock_sga: Default value: false.
If set to true, the entire SGA will be locked into physical memory (preventing it from being paged out). This may cause problems on systems with insufficient physical memory.

The parameters (and recommendations) are Unix generic.

 

The lock_sga parameter (which default AND recommended value is false): If you have sufficient memory on the server, you may consider setting it to true. (Forcing the SGA to be locked in physical memory).
On the other hand, if lock_sga is set to true, and you do not have suffficient memory, the SGA will stay in memory, and force other processe, like server processes to swap, and hence cause performance degradation.

For both the hidden and normal configuration parameters, we do not recommend deviations from the default values, without having detailed information on your specific configruation.

If you look at all Oracle products, options, features and parameters, there are billions of combinations. We do not have a complete catalog over each recommended values for each combiantion.

Know Oracle Process OS Scheduled Priority

Can you kindly define and explain of this parameter?

_os_sched_high_priority

 

Regarding _os_sched_high_priority :

Setting LMS priority automatically via _os_sched_high_priority
It has been proven that performance is increased when LMS processes are running in the real time priority class, as opposed to the timesharing class. The parameter _os_sched_high_priority was introduced in Oracle 10g Release 2, and it allows LMS processes to be automatically configured in the real time priority class at instance startup. This feature basically obsoletes the need to manually set the real time priority for the LMS processes using a C program or the renice command.

On Unix platforms, process priority changes are normally executed under the root privilege, and the LMS process priority changes are implemented through an executable � oradism � owned by root with the setuid bit set.

The default value for _os_sched_high_priority in 10.2.0.1 is 1. With _os_sched_high_priority = 1, it means that all LMS processes are set to priority 1 in the real time class. We suggest to always set _os_sched_high_priority=1 in the init.ora, regardless of the default, and only toggle the behavior by restoring the original privileges and permissions on the oradism executable. Other possible values for this parameter are:

� If set to 0, LMS processes are not prioritized at startup, they are kept at the timesharing class as in earlier releases.

� Values higher than 1 give LMS higher priority in the real time class. Those settings are not recommended because they might cause starvation for other Oracle processes, leading to performance degradation.

If LMS processes remain in the timesharing class at instance startup, despite _os_sched_high_priority set to 1, then ownership and/or privileges for oradism may not have been set properly. To correct / verify these settings:

$ ls -l oradism

-rwsr-sr-x 1 root dba 15871 Jun 13 10:32 oradism

# chown root:dba oradism

# chmod 6755 oradism

Note about Linux process priorities:

SCHED_OTHER
static prio 0 : shows dynamic priorities with ‘ps’, ranging from 59-99

SCHED_RR / SCHED_FIFO
static prio 1 -> shows as priority 58 with ‘ps’
static prio 11 -> shows as priority 48 with ‘ps’
static prio 59 -> shows as priority 0 with ‘ps’
static prio 60 -> shows as priority -1 with ‘ps’
static prio 99 -> shows as priority -40 with ‘ps’ (highest RT priority)

On Linux, the LMS process priority can be seen via �ps �efl | grep lms�:

$ ps -efl|grep lms

0 S spommere 2201 1 0 58 0 – 285308 schedu 14:39 ? 00:00:00 ora_lms0_appsu01

0 S spommere 2205 1 0 58 0 – 285308 schedu 14:39 ? 00:00:00 ora_lms1_appsu01

In the above example, the LMS processes are running in the real-time class.

In the example below, the change in process prioritization failed, and the process priority remained at 75, because the permissions on the oradism executable were incorrectly set.

$ ps -efl | grep lms

0 S spommere 2002 1 1 75 0 – 285307 schedu 14:38 ? 00:00:00 ora_lms0_appsu01

0 S spommere 2006 1 1 75 0 – 285308 schedu 14:38 ? 00:00:00 ora_lms1_appsu01

 

Reference: internal Note 341974.1

 

Unpublished note 433105.1: ‘LMS Real Time Priority in RAC 10g Release 2 – Things to Consider Before Changing’.

_os_sched_high_priority: Default value is 1.
Setting it to 0 means that all scheduling class manipulation will be disabled.
The parameter is mainly ised in RAC systems, where you may want specific procecces like LMS to run at a higher priority.

Any underscore (hidden) parameters (like _os_sched_high_priority) should not be set unless specificly instructed by Support either via a Service Request or via a MetaLink Note. In all other cases, it’s default value should be used.
(You may see examples of notes by querying in MetaLink with the word _os_sched_high_priority).

手动递增SCN号的几种方法:How to increase System Change Number by manual

 

 

手动递增SCN号的几种方法

 

除去下面几种,还有一种方法直接修改 实例的Global Lamport SCN,在SGA中由kcsgscn变量存储,对于一个实例来说这是唯一的源SCN,所有其他的SCN均由这个source scn所驱动。 这种递增方式是直接用oradebug 修改该Global Lamport SCN kcsgscn

 

 

如果自己搞不定可以找诗檀软件专业ORACLE数据库修复团队成员帮您恢复!

诗檀软件专业数据库修复团队

服务热线 : 13764045638   QQ号:47079569    邮箱:service@parnassusdata.com

 

 

SQL> oradebug setmypid
Statement processed.

 

SQL> select to_char(current_scn,’XXXXXXXXXXXX’) from v$database;

TO_CHAR(CURRE
————-
D3E1E

SQL>
SQL> oradebug DUMPvar SGA kcsgscn
kcslf kcsgscn_ [060012658, 060012688) = 000D3E1E 00000000 00000000 00000000 0000162D 00000000 00000000 00000000 00000000 00000000 60012338 00000000

 

ORADEBUG POKE 0x060012658 4 0xfffff

poke 命令的语法

<address> <length> <value>” allows you to modify a given region of memory (length of memory is limited to size of scalar C types)

 

SQL> select current_scn from v$database;

CURRENT_SCN
———–
1048583

 

SQL> select to_char(current_scn,’XXXXXXXXXXXX’) from v$database;

TO_CHAR(CURRE
————-
10000B

SQL> oradebug DUMPvar SGA kcsgscn
kcslf kcsgscn_ [060012658, 060012688) = 00100010 00000000 00000000 00000000 0000004E 00000000 00000000 00000000 00000000 00000000 60012338 00000000

 

 

 

 

 

How to jump SCN  by manual ,  this could be a problem:

1. We can bump up the SCN by using the procedure from Note: 386830.1

 

Bump the system SCN on the primary database to fix any metadata index corruptions for both
primary and physical standby databases. Set the following parameters in the init.ora and restart
the database in restricted mode to bump the system SCN of the primary database.
For Real Application Clusters, perform the steps on only one node of the cluster. 
Init.ora syntax:
*._allow_error_simulation = TRUE
*._smu_debug_mode = 268435456
If using an spfile, Oracle recommends creating a temporary init.ora using the CREATE PFILE SQL command.
SQL> create pfile='/tmp/initTMP.ora' from spfile='';
Then add the parameters to this temporary file.
To use the temporary init.ora file when starting the instance, include the 'PFILE' clause with the STARTUP SQL command i.e.
SQL> startup restrict pfile=
WARNING: These parameters should only be used for this fix and must be removed immediately afterwards in step 2.
If the above parameters are used through multiple database restarts, a complete database rebuild will be required.
To know the system SCN has been bumped, monitor the instance's alert.log for the following message:
advance SCN to wrap base xxxx
Where xxx represents the new wrap SCN.

 

 

 

 

2.EVENT: ADJUST_SCN – Quick Reference (Doc ID 30681.1)

 

 

 

WORKAROUND:
-----------
Searched in webiv (ora-1555, ora-604 see note:1063408.6 ) suggests workaround
is to adjust serial number using event
Will try : (30681.1)
alter session set events 'IMMEDIATE trace name ADJUST_SCN level 1';
ora-600 [2256][0][1073741824][1][293672646]
ERROR:
ORA-600 [2256][a][b][c][d][e]
VERSIONS:
versions 7.3.X, 8.0.X, 8.1.X
DESCRIPTION:
This exception indicates that you attempted to ADJUST_SCN but the level
supplied would be less that the current SCN.
ARGUMENTS:
a.  Requested SCN WRAP
b.  Requested SCN BASE
c.  Current SCN WRAP
d.  Current SCN BASE = [293672646]
*4 = 1174690584
will try level 2
ora-600 2256[0][2147483648][1][293672646]
level 3
ora-600 2256[0][3221225472][1][293672646]
Now, we increase the SCN on DST7 by using the ADJUST_SCN event -
(Note: do not use this event outside of your test environment)
set the following hidden parameter in init.ora on DST7 database and bounce
the database.
_allow_error_simulation=true
Now, the SCN is increased by doing -
alter system set events 'immediate trace name adjust_scn level ';
where  translates to (n*0x40000000) as the target SCN value. ie. n = 1
will set the SCN as 0x0000.40000000. For the testcase pick a value that is
larger than the current SCN on both databases by atleast 100000 SCNs (our
earlier SCN adjust threshold value).
alter system set events 'immediate trace name adjust_scn level 2';
select to_char(current_scn, 'xxxxxxxxxxxx') from v$database;

 

 

 

3.Note 552438.1 How To Adjust the SCN using parameter _MINIMUM_GIGA_SCN

 

 

 

 

Parameter: MINIMUM_GIGA_SCN
~~~~~~~~~~~~~~~~~~~~~~~~~~~
@Oracle8i:	HIDDEN
@Identifier:	kcmmsn
@Versions:	See <IVERS.MINIMUM_GIGA_SCN>
Values:
Related:
Description:	Minimum SCN to start with in 2^30 units
~~~~~~~~~~~~
Articles:	
<Event:ADJUST_SCN>
Overview of Init.Ora Parameter Reference notes

终极方案:
使用bbed修改datafile header实现修改scn

主要是修改system01.dbf datafile header kcvfh.kcvfhckp.kcvcpscn

helpbkup_us@oracle.com
helpkern_us@oracle.com
SQL> select * from v$version;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bi
PL/SQL Release 10.2.0.1.0 - Production
CORE    10.2.0.1.0      Production
TNS for Linux: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - Production
1* select name,CHECKPOINT_CHANGE# from v$datafile
SQL> /
/s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_system_9f2flf09_.dbf                  3905523
/s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_undotbs1_9f2flf52_.dbf                3905523
/s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_sysaux_9f2flf2v_.dbf                  3905523
/s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_users_9f2flf5g_.dbf                   3905523
/s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_example_9f2fmfto_.dbf                 3905523
/s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_youchuan_9f2fqwr4_.dbf                3905523
/s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_guobao_9f2fwkkt_.dbf                  3905523
/s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_tsoa_d_bjx6j57v_.dbf                  3905523
SQL>  select to_char(3905523,'XXXXXXXXXXXXX') from dual;
TO_CHAR(390552
--------------
3B97F3
SQL> oradebug tracefile_name
/s01/oracle/product/10.2.0/db_1/admin/MACLEAN1/udump/maclean1_ora_9468.trc
[oracle@vrh8 ~]$ cp /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_system_9f2flf09_.dbf  /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_system_9f2flf09_.dbf.bak
[oracle@vrh8 ~]$ bbed filename=/s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_system_9f2flf09_.dbf password=blockedit
BBED: Release 2.0.0.0.0 - Limited Production on Tue Mar 24 16:50:39 2015
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
************* !!! For Oracle Internal Use only !!! ***************
BBED> set mode edit
MODE            Edit
BBED>  set blocksize 8192
BLOCKSIZE       8192
BBED> set block 1
BLOCK#          1
BBED> map
File: /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_system (0)
Block: 1                                     Dba:0x00000000
------------------------------------------------------------
Data File Header
struct kcvfh, 676 bytes                    @0       
ub4 tailchk                                @8188    
BBED> p kcvfh
struct kcvfh, 676 bytes                     @0       
struct kcvfhbfh, 20 bytes                @0       
ub1 type_kcbh                         @0        0x0b
ub1 frmt_kcbh                         @1        0xa2
ub1 spare1_kcbh                       @2        0x00
ub1 spare2_kcbh                       @3        0x00
ub4 rdba_kcbh                         @4        0x00400001
ub4 bas_kcbh                          @8        0x00000000
ub2 wrp_kcbh                          @12       0x0000
ub1 seq_kcbh                          @14       0x01
ub1 flg_kcbh                          @15       0x04 (KCBHFCKV)
ub2 chkval_kcbh                       @16       0x4fc6
ub2 spare3_kcbh                       @18       0x0000
struct kcvfhhdr, 76 bytes                @20      
ub4 kccfhswv                          @20       0x00000000
ub4 kccfhcvn                          @24       0x0a200100
ub4 kccfhdbi                          @28       0x157f2927
text kccfhdbn[0]                      @32      M
text kccfhdbn[1]                      @33      A
text kccfhdbn[2]                      @34      C
text kccfhdbn[3]                      @35      L
text kccfhdbn[4]                      @36      E
text kccfhdbn[5]                      @37      A
text kccfhdbn[6]                      @38      N
text kccfhdbn[7]                      @39      1
ub4 kccfhcsq                          @40       0x00000675
ub4 kccfhfsz                          @44       0x00010900
s_blkz kccfhbsz                       @48       0x00
ub2 kccfhfno                          @52       0x0001
ub2 kccfhtyp                          @54       0x0003
ub4 kccfhacid                         @56       0x00000000
ub4 kccfhcks                          @60       0x00000000
text kccfhtag[0]                      @64       
text kccfhtag[1]                      @65       
text kccfhtag[2]                      @66       
text kccfhtag[3]                      @67       
text kccfhtag[4]                      @68       
text kccfhtag[5]                      @69       
text kccfhtag[6]                      @70       
text kccfhtag[7]                      @71       
text kccfhtag[8]                      @72       
text kccfhtag[9]                      @73       
text kccfhtag[10]                     @74       
text kccfhtag[11]                     @75       
text kccfhtag[12]                     @76       
text kccfhtag[13]                     @77       
text kccfhtag[14]                     @78       
text kccfhtag[15]                     @79       
text kccfhtag[16]                     @80       
text kccfhtag[17]                     @81       
text kccfhtag[18]                     @82       
text kccfhtag[19]                     @83       
text kccfhtag[20]                     @84       
text kccfhtag[21]                     @85       
text kccfhtag[22]                     @86       
text kccfhtag[23]                     @87       
text kccfhtag[24]                     @88       
text kccfhtag[25]                     @89       
text kccfhtag[26]                     @90       
text kccfhtag[27]                     @91       
text kccfhtag[28]                     @92       
text kccfhtag[29]                     @93       
text kccfhtag[30]                     @94       
text kccfhtag[31]                     @95       
ub4 kcvfhrdb                             @96       0x00400179
struct kcvfhcrs, 8 bytes                 @100     
ub4 kscnbas                           @100      0x00000008
ub2 kscnwrp                           @104      0x0000
ub4 kcvfhcrt                             @108      0x221e01bf
ub4 kcvfhrlc                             @112      0x31dd7868
struct kcvfhrls, 8 bytes                 @116     
ub4 kscnbas                           @116      0x00080634
ub2 kscnwrp                           @120      0x0000
ub4 kcvfhbti                             @124      0x00000000
struct kcvfhbsc, 8 bytes                 @128     
ub4 kscnbas                           @128      0x00000000
ub2 kscnwrp                           @132      0x0000
ub2 kcvfhbth                             @136      0x0000
ub2 kcvfhsta                             @138      0x2000 (NONE)
struct kcvfhckp, 36 bytes                @484     
struct kcvcpscn, 8 bytes              @484     
ub4 kscnbas                        @484      0x003b97f3
ub2 kscnwrp                        @488      0x0000
ub4 kcvcptim                          @492      0x342a9561
ub2 kcvcpthr                          @496      0x0001
union u, 12 bytes                     @500     
struct kcvcprba, 12 bytes          @500     
ub4 kcrbaseq                    @500      0x00000052
ub4 kcrbabno                    @504      0x00013fc0
ub2 kcrbabof                    @508      0x0010
ub1 kcvcpetb[0]                       @512      0x02
ub1 kcvcpetb[1]                       @513      0x00
ub1 kcvcpetb[2]                       @514      0x00
ub1 kcvcpetb[3]                       @515      0x00
ub1 kcvcpetb[4]                       @516      0x00
ub1 kcvcpetb[5]                       @517      0x00
ub1 kcvcpetb[6]                       @518      0x00
ub1 kcvcpetb[7]                       @519      0x00
ub4 kcvfhcpc                             @140      0x00000087
ub4 kcvfhrts                             @144      0x3427f1a8
ub4 kcvfhccc                             @148      0x00000086
struct kcvfhbcp, 36 bytes                @152     
struct kcvcpscn, 8 bytes              @152     
ub4 kscnbas                        @152      0x00000000
ub2 kscnwrp                        @156      0x0000
ub4 kcvcptim                          @160      0x00000000
ub2 kcvcpthr                          @164      0x0000
union u, 12 bytes                     @168     
struct kcvcprba, 12 bytes          @168     
ub4 kcrbaseq                    @168      0x00000000
ub4 kcrbabno                    @172      0x00000000
ub2 kcrbabof                    @176      0x0000
ub1 kcvcpetb[0]                       @180      0x00
ub1 kcvcpetb[1]                       @181      0x00
ub1 kcvcpetb[2]                       @182      0x00
ub1 kcvcpetb[3]                       @183      0x00
ub1 kcvcpetb[4]                       @184      0x00
ub1 kcvcpetb[5]                       @185      0x00
ub1 kcvcpetb[6]                       @186      0x00
ub1 kcvcpetb[7]                       @187      0x00
ub4 kcvfhbhz                             @312      0x00000000
struct kcvfhxcd, 16 bytes                @316     
ub4 space_kcvmxcd[0]                  @316      0x00000000
ub4 space_kcvmxcd[1]                  @320      0x00000000
ub4 space_kcvmxcd[2]                  @324      0x00000000
ub4 space_kcvmxcd[3]                  @328      0x00000000
word kcvfhtsn                            @332      0
ub2 kcvfhtln                             @336      0x0006
text kcvfhtnm[0]                         @338     S
text kcvfhtnm[1]                         @339     Y
text kcvfhtnm[2]                         @340     S
text kcvfhtnm[3]                         @341     T
text kcvfhtnm[4]                         @342     E
text kcvfhtnm[5]                         @343     M
text kcvfhtnm[6]                         @344      
text kcvfhtnm[7]                         @345      
text kcvfhtnm[8]                         @346      
text kcvfhtnm[9]                         @347      
text kcvfhtnm[10]                        @348      
text kcvfhtnm[11]                        @349      
text kcvfhtnm[12]                        @350      
text kcvfhtnm[13]                        @351      
text kcvfhtnm[14]                        @352      
text kcvfhtnm[15]                        @353      
text kcvfhtnm[16]                        @354      
text kcvfhtnm[17]                        @355      
text kcvfhtnm[18]                        @356      
text kcvfhtnm[19]                        @357      
text kcvfhtnm[20]                        @358      
text kcvfhtnm[21]                        @359      
text kcvfhtnm[22]                        @360      
text kcvfhtnm[23]                        @361      
text kcvfhtnm[24]                        @362      
text kcvfhtnm[25]                        @363      
text kcvfhtnm[26]                        @364      
text kcvfhtnm[27]                        @365      
text kcvfhtnm[28]                        @366      
text kcvfhtnm[29]                        @367      
ub4 kcvfhrfn                             @368      0x00000001
struct kcvfhrfs, 8 bytes                 @372     
ub4 kscnbas                           @372      0x00000000
ub2 kscnwrp                           @376      0x0000
ub4 kcvfhrft                             @380      0x00000000
struct kcvfhafs, 8 bytes                 @384     
ub4 kscnbas                           @384      0x00000000
ub2 kscnwrp                           @388      0x0000
ub4 kcvfhbbc                             @392      0x00000000
ub4 kcvfhncb                             @396      0x00000000
ub4 kcvfhmcb                             @400      0x00000000
ub4 kcvfhlcb                             @404      0x00000000
ub4 kcvfhbcs                             @408      0x00000000
ub2 kcvfhofb                             @412      0x000a
ub2 kcvfhnfb                             @414      0x000a
ub4 kcvfhprc                             @416      0x221e01a8
struct kcvfhprs, 8 bytes                 @420     
ub4 kscnbas                           @420      0x00000001
ub2 kscnwrp                           @424      0x0000
struct kcvfhprfs, 8 bytes                @428     
ub4 kscnbas                           @428      0x00000000
ub2 kscnwrp                           @432      0x0000
ub4 kcvfhtrt                             @444      0x00000000
BBED> p kcvfhckp
struct kcvfhckp, 36 bytes                   @484     
struct kcvcpscn, 8 bytes                 @484     
ub4 kscnbas                           @484      0x003b97f3
ub2 kscnwrp                           @488      0x0000
ub4 kcvcptim                             @492      0x342a9561
ub2 kcvcpthr                             @496      0x0001
union u, 12 bytes                        @500     
struct kcvcprba, 12 bytes             @500     
ub4 kcrbaseq                       @500      0x00000052
ub4 kcrbabno                       @504      0x00013fc0
ub2 kcrbabof                       @508      0x0010
ub1 kcvcpetb[0]                          @512      0x02
ub1 kcvcpetb[1]                          @513      0x00
ub1 kcvcpetb[2]                          @514      0x00
ub1 kcvcpetb[3]                          @515      0x00
ub1 kcvcpetb[4]                          @516      0x00
ub1 kcvcpetb[5]                          @517      0x00
ub1 kcvcpetb[6]                          @518      0x00
ub1 kcvcpetb[7]                          @519      0x00
BBED> set offset 484
OFFSET          484
BBED> modify /x 0xF397
File: /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_system (0)
Block: 1                Offsets:  484 to  995           Dba:0x00000000
------------------------------------------------------------------------
f397f4f3 00000000 61952a34 01000000 52000000 c03f0100 1000a865 02000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0d000d00 0d000100 00000000 00000000 00000000 02004000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
<32 bytes per line>
BBED> set offset 486
OFFSET          486
BBED> modify /x 0x4B00
File: /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_system (0)
Block: 1                Offsets:  486 to  997           Dba:0x00000000
------------------------------------------------------------------------
4b000000 00006195 2a340100 00005200 0000c03f 01001000 a8650200 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000d00 
0d000d00 01000000 00000000 00000000 00000200 40000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
<32 bytes per line>
BBED> p kcvfhckp
struct kcvfhckp, 36 bytes                   @484     
struct kcvcpscn, 8 bytes                 @484     
ub4 kscnbas                           @484      0x004b97f3
ub2 kscnwrp                           @488      0x0000
ub4 kcvcptim                             @492      0x342a9561
ub2 kcvcpthr                             @496      0x0001
union u, 12 bytes                        @500     
struct kcvcprba, 12 bytes             @500     
ub4 kcrbaseq                       @500      0x00000052
ub4 kcrbabno                       @504      0x00013fc0
ub2 kcrbabof                       @508      0x0010
ub1 kcvcpetb[0]                          @512      0x02
ub1 kcvcpetb[1]                          @513      0x00
ub1 kcvcpetb[2]                          @514      0x00
ub1 kcvcpetb[3]                          @515      0x00
ub1 kcvcpetb[4]                          @516      0x00
ub1 kcvcpetb[5]                          @517      0x00
ub1 kcvcpetb[6]                          @518      0x00
ub1 kcvcpetb[7]                          @519      0x00
BBED> sum
Check value for File 0, Block 1:
current = 0x4fc6, required = 0x4fb6
BBED> sum apply
Check value for File 0, Block 1:
current = 0x4fb6, required = 0x4fb6
BBED> verify
DBVERIFY - Verification starting
FILE = /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_system_9f2flf09_.dbf
BLOCK = 1
DBVERIFY - Verification complete
Total Blocks Examined         : 1
Total Blocks Processed (Data) : 0
Total Blocks Failing   (Data) : 0
Total Blocks Processed (Index): 0
Total Blocks Failing   (Index): 0
Total Blocks Empty            : 0
Total Blocks Marked Corrupt   : 0
Total Blocks Influx           : 0
SQL> select file#,name,checkpoint_change# from v$datafile;
1 /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_system_9f2flf09_.dbf                  3905523
2 /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_undotbs1_9f2flf52_.dbf                3905523
3 /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_sysaux_9f2flf2v_.dbf                  3905523
4 /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_users_9f2flf5g_.dbf                   3905523
5 /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_example_9f2fmfto_.dbf                 3905523
6 /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_youchuan_9f2fqwr4_.dbf                3905523
7 /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_guobao_9f2fwkkt_.dbf                  3905523
8 /s01/oracle/product/10.2.0/db_1/oradata/MACLEAN1/datafile/o1_mf_tsoa_d_bjx6j57v_.dbf                  3905523
8 rows selected.
SQL> select file#,FUZZY,CHECKPOINT_CHANGE#        from v$datafile_header;
1 NO             4954099
2 NO             3905523
3 NO             3905523
4 NO             3905523
5 NO             3905523
6 NO             3905523
7 NO             3905523
8 NO             3905523
8 rows selected.
SQL> alter database open;
Database altered.
SQL> select file#,FUZZY,CHECKPOINT_CHANGE#        from v$datafile_header;
1 YES            4954100
2 YES            4954100
3 YES            4954100
4 YES            4954100
5 YES            4954100
6 YES            4954100
7 YES            4954100
8 YES            4954100
8 rows selected.
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup;
ORACLE instance started.
Total System Global Area  591396864 bytes
Fixed Size                  2022536 bytes
Variable Size             180355960 bytes
Database Buffers          402653184 bytes
Redo Buffers                6365184 bytes
Database mounted.
Database opened.

Know more about redo log buffer and latches

1.
The Total size of the log buffer is determined by LOG_BUFFER parameter.

2.
Only Server process may pin a data block in exclusive mode.

3.
LGWR writes to the redo log files when:

  • The redo log buffer is 1/3 full.
  • 1 MB of data have been written to the redo log buffer.
  • A 3-second time-out occurs.
  • commit!
  • before dbwr write out dirty buffers
  • A thread is closed

 

4.
the correct sequence for the LGWR algorithm is :

  1. Acquire the redo writing and redo allocation latches
  2. determine the buffer to write out
  3. Release the redo allocation latch
  4. determine how many writes are required

 

5.
In Oracle8i, the redo copy latch is always acquired regardless of the redo size.

Because the parameter LOG_SMALL_ENTRY_MAX_SIZE is obsolete, a redo copy latch is always acquired.

6.
Three most relevant redo events under normal operations:

  • Log file parallel write
  • Log buffer space
  • Log file sync

 

7.
relevant redo statistics and their purpose

  • REDO writes                                                 === Number of times the log buffer is written
  • redo blocks written                                === Number of times the log buffer is written
  • redo write time                                          === Total time required to write all the redos to disk
  • redo buffer allocation retires         === Total number of retries necessary to allocate space in the redo buffer

 

8.
Log buffer contention is typically indicated by Redo buffer allocation retries .

The buffer allocation retries indicates that a process has to continually try to allocate buffers that are not available

9.
Redo buffer allocation retries can be gathered by querying the name and value columns from V$ dynamic views:
V$sesstat
V$sysstat

10.
Stripe the redo log files across physical disks will help flush the redo buffer faster.

The redo log file write batch is 128K, so striping the redo logs across 8 disks with a stripe size of 16K could improve the write time by as much as 75%.

11.
The number of redo copy latches can be defined by setting _Log_simultaneous_copies .

The parameter begins with an underscore because in 8i it is a hidden parameter.

12.
The purpose of the redo writing latch is to: Prevent multiple processes from posting
LGWR when there is no space in the buffer .

The redo writing latch frees space in log buffer and does not want
processes writing to the buffer while space is being freed

13.
_log_io_size is set to reduce contention for the redo writing latch.

But notice that it is a hidden parameter. This is the number of used redo blocks that will automatically initiate a log write.

14.
A standby database must be refreshed following a nologging operation.

When nologging occurs, the redo logs of the standby database are not written to.

15.
log_small_entry_max_size is used to determine if a redo copy latch is required based upon the redo entry size,

however, this parameter is obsolete in Oracle8i, as a copy latch is always acquired.

_log_simultaneous_copies determines the number of redo copy latches to allocate.

Note that this is a hidden parameter in Oracle8i because it is not recommended to have more than one copy latch.

log_checkpoint_interval determines the need for a checkpoint.

How does cpu_count parameter affect instance?

Parameter cpu_count is determined by Oracle Software when instance started, But we can set it manually. This parameter can affect lots of  hidden initialization parameters,see:

SQL> select * from v$version;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi
PL/SQL Release 10.2.0.4.0 - Production
CORE    10.2.0.4.0      Production
TNS for Linux: Version 10.2.0.4.0 - Production
NLSRTL Version 10.2.0.4.0 - Production
SQL> host cat /proc/cpuinfo|grep processor
processor       : 0
processor       : 1
SQL> show parameter cpu_count
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
cpu_count                            integer     2
create table  cpu_2_parameters as 
SELECT x.ksppinm NAME, y.ksppstvl VALUE, x.ksppdesc describ
FROM SYS.x$ksppi x, SYS.x$ksppcv y
WHERE x.inst_id = USERENV ('Instance')
AND y.inst_id = USERENV ('Instance')
AND x.indx = y.indx;
SQL> alter system set cpu_count=128 scope=spfile;
System altered.
SQL> startup force;
ORACLE instance started.
Total System Global Area 1702887424 bytes
Fixed Size                  2093192 bytes
Variable Size             486543224 bytes
Database Buffers         1073741824 bytes
Redo Buffers              140509184 bytes
Database mounted.
Database opened.
SQL> show parameter cpu_count
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
cpu_count                            integer     128
SQL> create table  cpu_128_parameters as 
2  SELECT x.ksppinm NAME, y.ksppstvl VALUE, x.ksppdesc describ
3   FROM SYS.x$ksppi x, SYS.x$ksppcv y
4   WHERE x.inst_id = USERENV ('Instance')
5   AND y.inst_id = USERENV ('Instance')
6   AND x.indx = y.indx; 
Table created.
SQL> col name for a35
SQL> set linesize 200 pagesize 2000;
SQL> col "while_cpu_count=   2" for a20
SQL> col "while_cpu_count= 128" for a02
SQL>  col "while_cpu_count= 128" for a20
SQL> SELECT a.name,
2    a.value "while_cpu_count=   2",
3    b.value "while_cpu_count= 128",
4    a.describ
5  FROM cpu_2_parameters a,
6    cpu_128_parameters b
7  WHERE a.name=b.name
8  AND a.value!=b.value 
9  ORDER BY 1;
NAME                                while_cpu_count=   2 while_cpu_count= 128 DESCRIB
----------------------------------- -------------------- -------------------- --------------------------------------------------------------------------------
__db_cache_size                     33554432             536870912            Actual size of DEFAULT buffer pool for standard block size buffers
_cursor_db_buffers_pinned           445                  841                  additional number of buffers a cursor can pin at once
_db_block_buffers                   67184                126464               Number of database blocks cached in memory: hidden parameter
_db_block_lru_latches               8                    512                  number of lru latches
_enqueue_hash_chain_latches         2                    128                  enqueue hash chain latches
_enqueue_locks                      2300                 2490                 locks for managed enqueues
_flashback_generation_buffer_size   8388608              536870912            flashback generation buffer size
_log_parallelism_max                2                    8                    Maximum number of log buffer strands
_log_simultaneous_copies            4                    256                  number of simultaneous copies into redo buffer(# of copy latches)
_num_longop_child_latches           2                    128                  number of child latches for long op array
_parallel_min_message_pool          903840               1076000              minimum size of shared pool memory to reserve for pq servers
_small_table_threshold              1343                 2529                 threshold level of table size for direct reads
cpu_count                           2                    128                  number of CPUs for this instance
db_cache_size                       33554432             536870912            Size of DEFAULT buffer pool for standard block size buffers
db_writer_processes                 1                    16                   number of background database writer  processes to start
log_buffer                          6104064              136249344            redo circular buffer size
parallel_max_servers                40                   135                  maximum parallel query servers per instance
sga_max_size                        1065353216           1702887424           max total SGA size
SQL> show parameter sga_max_size
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
sga_max_size                         big integer 1016M

It looks like sga may grow while the instance has more processors. Oracle Parallel Servers can has more differ with cpu_count . Sometimes this parameter make performance issues.

[Repost]List of X$ Tables

This is a summary list of X$ Table Definitions - Last revision was 7.3.2
The main purpose of this note is to show the naming conventions.
[K]ernel Layer
[2]-Phase Commit
[G]lobal [T]ransaction [E]ntry
X$K2GTE  - Current 2PC tx
X$K2GTE2 - Current 2PC tx
[C]ache Layer
[B]uffer Management
Buffer [H]ash
X$BH - Hash Table
Buffer LRU Statistics
X$KCBCBH - [C]urrent [B]uffers (buckets) - lru_statistics
X$KCBRBH - [R]ecent [B]uffers (buckets) - lru_extended
Buffer [WAIT]s
X$KCBWAIT  - Waits by block class
X$KCBFWAIT - Waits by File
[W]orking Sets - 7.3 or higher
X$KCBWDS - Set [D]escriptors
[C]ontrol File Management
[C]ontrol [F]ile List - 7.0.16 or higher
X$KCCCF - Control File Names & status
[D]atabase [I]nformation
X$KCCDI - Database Information
Data [F]iles
X$KCCFE - File [E]ntries ( from control file )
X$KCCFN - [F]ile [N]ames
[L]og Files
X$KCCLE - Log File [E]ntries
X$KCCLH - Log [H]istory ( archive entries )
Thread Information
X$KCCRT - [R]edo [T]hread Information
[F]ile Management
X$KCFIO - File [IO] Statistics
[L]ock Manager Component ( LCK )
[H]ash and Bucket Tables - 7.0.15 to 7.1.1, and 7.2.0 or higher
X$KCLFH - File [H]ash Table
X$KCLFI - File Bucket Table
X$LE - Lock [E]lements
X$LE_STAT - Lock Conversion [STAT]istics
X$KCLFX - Lock Element [F]ree list statistics - 7.3 or higher
X$KCLLS - Per LCK free list statistics - 7.3 or higher
X$KCLQN - [N]ame (hash) table statistics - 7.3 or higher
[R]edo Component
[M]edia recovery  - kcra.h - 7.3 or higher
X$KCRMF - [F]ile context
X$KCRMT - [T]hread context
X$KCRMX - Recovery Conte[X]t
[F]ile read
X$KCRFX - File Read Conte[X]t -  7.3 or higher
Reco[V]ery Component
[F]ile [H]eaders
X$KCVFH - All file headers
X$KCVFHMRR - Files with [M]edia [R]ecovery [R]equired
X$KCVFHONL - [ONL]ine File headers
[K]ompatibility Management - 7.1.1 or higher
X$KCKCE - [C]ompatibility Segment [E]ntries
X$KCKTY - Compatibility [TY]pes
X$KCKFM - Compatibility [F]or[M]ats ( index into X$KCKCE )
[D]ata Layer
Sequence [N]umber Component
X$KDNCE - Sequence [C]ache [E]ntries - 7.2 or lower
[S]equence Enqueues - common area for enqueue objects
X$KDNSSC - [C]ache Enqueue Objects - 7.2 or lower
X$KDNSSF - [F]lush Enqueue Objects - 7.2 or lower
X$KDNST - Cache [ST]atistics - 7.2 or lower
Inde[X] Block Component
X$KDXHS - Index [H]i[S]togram
X$KDXST - Index [ST]atistics
[G]eneric Layer
[H]eap Manager
X$KGHLU - State (summary) of [L]R[U] heap(s) - defined in ksmh.h
[I]nstantiation Manager
[C]ursor [C]ache
X$KGICC - Session statistics - defined in kqlf.h
X$KGICS - System wide statistics - defined in kqlf.h
[L]ibrary Cache Manager  ( defined and mapped from kqlf )
Bind Variables
X$KKSBV - Library Object [B]ind [V]ariables
Object Cache
X$KGLOB - All [OB]jects
X$KGLTABLE   - Filter for [TABLE]s
X$KGLBODY    - Filter for [BODY] ( packages )
X$KGLTRIGGER - Filter for [TRIGGER]s
X$KGLINDEX   - Filter for [INDEX]es
X$KGLCLUSTER - Filter for [CLUSTER]s
X$KGLCURSOR  - Filter for [CURSOR]s
Cache Dependency
X$KGLDP - Object [D]e[P]endency table
X$KGLRD - [R]ead only [D]ependency table - 7.3 or higher
Object Locks
X$KGLLK - Object [L]oc[K]s
Object Names
X$KGLNA - Object [NA]mes (sql text)
X$KGLNA1 - Object [NA]mes (sql text) with newlines - 7.2.0 or higher
Object Pins
X$KGLPN - Object [P]i[N]s
Cache Statistics
X$KGLST - Library cache [ST]atistics
Translation Table
X$KGLTR - Address [TR]anslation
Access Table
X$KGLXS - Object Access Table
Authorization Table - 7.1.5 or higher
X$KGLAU - Object Authorization table
Latch Cleanup - 7.0.15 or higher
X$KGLLC - [L]atch [C]leanup for Cache/Pin Latches
[K]ompile Layer
[S]hared Objects
X$KKSAI - Cursor [A]llocation [I]nformation - 7.3.2 or higher
[L]oader
[L]ibrary
X$KLLCNT - [C]o[NT]rol Statistics
X$KLLTAB - [TAB]le Statistics
[M]ulti-Threaded Layer
[C]ircuit component
X$KMCQS - Current [Q]ueue [S]tate
X$KMCVC - [V]irtual [C]ircuit state
[M]onitor Server/dispatcher
[D]ispatcher
X$KMMDI - [D]ispatcher [I]nfo (status)
X$KMMDP - [D]ispatcher Config ( [P]rotocol info )
[S]erver
X$KMMSI - [S]erver [I]nfo ( status )
X$KMMSG - [SG]a info ( global statistics)
X$KMMRD - [R]equest timing [D]istributions
s[Q]l Version and Option Layer
Kernel [V]ersions
X$VERSION - Library versions
Kernel [O]ptions - 7.1.3 or higher
X$OPTION - Server Options
[Q]uery Layer
[D]ictionary Cache Management
X$KQDPG - [PG]a row cache cursor statistics
[F]ixed Tables/views Management
X$KQFCO - Table [CO]lumn definitions
X$KQFDT - [D]erived [T]ables
X$KQFSZ - Kernel Data structure type [S]i[Z]es
X$KQFTA - Fixed [TA]bles
X$KQFVI - Fixed [VI]ews
X$KQFVT - [V]iew [T]ext definition - 7.2.0 or higher
[R]ow Cache Management
X$KQRST - Cache [ST]atistics
X$KQRPD - [P]arent Cache [D]efinition - 7.1.5 or higher
X$KQRSD - [S]ubordinate Cache [D]efinition - 7.1.5 or higher
[S]ervice Layer
[B]ackground Management
[D]etached Process
X$KSBDD - Detached Process [D]efinition (info)
X$KSBDP - Detached [P]rocess Descriptor (name)
X$MESSAGES - Background Message table
[I]nstance [M]anagement - 7.3 or higher
X$KSIMAT - Instance [AT]tributes
X$KSIMAV - [A]ttribute [V]alues for all instances
X$KSIMSI - [S]erial and [I]nstance numbers
[L]ock Management
[E]vent Waits
X$KSLED - Event [D]escriptors
X$KSLEI - [I]nstance wide statistics since startup
X$KSLES - Current [S]ession statistics
[L]atches
X$KSLLD - Latch [D]escriptor (name)
X$KSLLT - Latch statistics [ + Child latches @ 7.3 or higher ]
X$KSLLW - Latch context ( [W]here ) descriptors - 7.3 or higher
X$KSLPO - Latch [PO]st statistics - 7.3 or higher
X$KSLWSC- No[W]ait and [S]leep [C]ount stats by Context -7.3 or higher
[M]emory Management
[C]ontext areas
X$KSMCX - E[X]tended statistics on usage - 7.3.1 or lower
Heap Areas
X$KSMSP - SGA Hea[P]
X$KSMPP - [P]GA Hea[P] - 7.3.2 and above
X$KSMUP - [U]GA Hea[P] - 7.3.2 and above
X$KSMHP - Any [H]ea[P] - 7.3.2 and above
X$KSMSPR- [S]hared [P]ool [R]eserved List - 7.1.5 or higher
[L]east recently used shared pool chunks
X$KSMLRU - LR[U] flushes from the shared pool
[S]GA Objects
X$KSMSD - Size [D]efinition for Fixed/Variable summary
X$KSMSS - Statistics (lengths) of SGA objects
SGA [MEM]ory
X$KSMMEM - map of the entire SGA - 7.2.0 or higher
X$KSMFSV - Addresses of [F]ixed [S]GA [V]ariables - 7.2.1 or higher
[P]arameter Component
X$KSPPI  - [P]arameter [I]nfo ( Names )
X$KSPPCV - [C]urrent Session [V]alues - 7.3.2 or above
X$KSPPSV - [S]ystem [V]alues - 7.3.2 or above
En[Q]ueue Management
X$KSQDN - Global [D]atabase [N]ame
X$KSQEQ - [E]n[Q]ueue Object
X$KSQRS - Enqueue [R]e[S]ource
X$KSQST - Enqueue [S]tatistics by [T]ype
[U]ser Management
[C]ost
X$KSUCF - Cost [F]unction (resource limit)
[L]icence
X$KSULL - Licence [L]imits
[L]anguage Manager
X$NLS_PARAMETERS - NLS parameters
X$KSULV - NLS [V]alid Values - 7.1.2 or higher
[MY] [ST]atistics
X$KSUMYSTA - [MY] [ST]atisics (current session)
[P]rocess Info
X$KSUPL - Process (resource) [L]imits
X$KSUPRLAT - [LAT]ch Holder
X$KSUPR - Process object
[R]esource
X$KSURU - Resource [U]sage
[S]tatistics
X$KSUSD - [D]escriptors (statistic names)
X$KSUSGSTA - [G]lobal [ST]atistics
[SE]ssions
X$KSUSECST - Session status for events
X$KSUSESTA - Session [STA]tistics
X$KSUSECON - [CON]nection Authentication - 7.2.1 or higher
X$KSUSE - [SE]ssion Info
X$KSUSIO - [S]ystem [IO] statistics per session
[T]imer
X$KSUTM - Ti[M]e in 1/100th seconds
Instance [X]
X$KSUXSINST - [INST]ance state
[T]race management
X$TRACE - Current traced events
X$TRACES - All possible traces
X$KSTEX - Code [EX]ecution - 7.2.1 or higher
E[X]ecution Management
Device/Node [A]ffinity - 7.3.2 and above
X$KSXAFA - Current File/Node Affinity
[T]ransaction Layer
Table [A]ccess [D]efinition
X$KTADM - D[M]L lock
[C]ontrol Component
X$KTCXB - Transaction O[B]ject
[S]or[T] Segments - 7.3 or higher
X$KTSTSSD - [S]ort [S]egment [D]escriptor - per tablespace statistics
[T]ablespace
X$KTTVS - [V]alid [S]aveundo
[U]ndo
X$KTURD - Inuse [D]escriptors
X$KTUXE - Transaction [E]ntry (table) - 7.3.2 or above
Performance Layer [V] - 7.0.16 or higher
[I]nformation tables
X$KVII - [I]nitialisation Instance parameters
X$KVIS - [S]izes of structure elements
X$KVIT - [T]ransitory Instance parameters
Security Layer [Z]
[D]ictionary Component
X$KZDOS - [OS] roles
[S]ecurity State
X$KZSPR - Enabled [PR]ivileges
X$KZSRO - Enabled [RO]les
[R]emote Logins - 7.1.1 or higher
X$KZSRT - [R]emote Password File [T]able entries
E[X]ecution Layer
Parallel Query (Execute [F]ast) - 7.1.1 or higher
[P]rocess and Queue Manager
Statistics - 7.1.3 or higher
X$KXFPYS - S[YS]tem Statistics
X$KXFPDP - [D]etached [P]rocess (slave) statistics
X$KXFQSROW - Table [Q]ueue Statistics - 7.3.2 or higher
[C]oordinator Component
X$KXFPCST - Query [ST]atistics
X$KXFPCMS - [M]essage [S]tatistics
X$KXFPCDS - [D]equeue [S]tatistics
[S]lave Component
X$KXFPSST - Query [ST]atistics
X$KXFPSMS - [M]essage [S]tatistics
X$KXFPCDS - [D]equeue [S]tatistics
[S]hared Cursor
X$KXSBD - [B]ind [D]ata - 7.3.2 and above
X$KXSCC - SQL [C]ursor [C]ache Data - 7.3.2 and above
[N]etwork Layer - 7.0.15 or higher
Network [CO]nnections
X$UGANCO - Current [N]etwork [CO]nnections

How to trigger ORA-00600,ORA-7445 by manual

Sometime we’d like to trigger ORA-00600/7445 internal errors for testing purpose, But it’s not easy if you don’t know a little trick like below:

declare
a exception;
pragma exception_init(a,-600);
begin
raise a;
end;
declare
*
ERROR at line 1:
ORA-00600: internal error code, arguments: [], [], [], [], [], [], [], [], [],
[], [], []
ORA-06512: at line 5
or
oradebug unit_test dbke_test dde_flow_kge_ora ouch! 0 0
7445:
select spidfrom v$processp, v$sessions
where p.addr= paddr
and sid= sys_context('USERENV','SID');
kill -SEGV $PID
or
declare
a exception;
pragma exception_init(a,-7445);
begin
raise a;
end;

VIEW:X$KCCRS-Controlfile Record Section directory (8.0 – 8.1)

View:   X$KCCRS
[K]ernel [C]ache [C]ontrolfile management
controlfile [R]ecord [S]ection directory
Column      Type           Description
--------    ----           -----------
ADDR        RAW(4)         address of this row/entry in the SGA
INDX        NUMBER         control file record type
The following are the non-circular-reuse record types:
KCCDEDBI     0             DataBase Info record
KCCDECKP     1             Checkpoint progress
KCCDERTH     2             Redo THread record
KCCDELOG     3             LOgFile record
KCCDEDBF     4             DataBase File record
KCCDENAM     5             file NAMe record
KCCDETBS     6     8.x     TaBleSpace record
KCCDERS1     7     8.0     reserved for future use. non-circular re-use
KCCDETFL     7     8.1     Temporary File record
KCCDERS2     8     8.x     reserved for future use. non-circular re-use
KCCDERMC     8     9.x     RMan Configuration record
The following are the circular-Reuse record types:
KCCDELHR     9     8.x     Log History Record
KCCDEORR    10     8.x     Offline Range Record
KCCDEALR    11     8.x     Archived Log Record
KCCDEBSR    12     8.x     Backup Set Record
KCCDEBPR    13     8.x     Backup Piece Record
KCCDEBFR    14     8.x     Backup dataFile Record
KCCDEBLR    15     8.x     Backup redoLog Record
KCCDEDCR    16     8.x     Datafile Copy Record
KCCDEFCR    17     8.x     backup dataFile Corruption Record
KCCDECCR    18     8.x     datafile Copy Corruption Record
KCCDEDLR    19     8.x     DeLeted object Record
KCCDERS3    20     8.0      reserved for future use. circular re-use.
KCCDEPCR    20     8.1     proxy copy record
KCCDERS4    21     8.x     reserved for future use. circular re-use.
KCCDENEN     6     7.3     actual # entry types in control file
KCCDEMEN    10     7.3     max possible # entry types in control file
KCCDEMNR     9     8.x     MiNimum circular-Reuse record type
KCCDEMXR    21     8.x     MaXimum circular-Reuse record type
KCCDEMAX    22     8.x     MAX # record types in current format
INST_ID     NUMBER         oracle instance number
RSLBN       NUMBER         Logical Blk Number (base 1) of section start
RSRSZ       NUMBER         Record SiZe in bytes
RSNUM       NUMBER         NUMber of usable record slots in section
RSNUS       NUMBER         circ-reuse: Number of in-USe slots in section
non-circ-reuse: highest USed slot Number
RSIOL       NUMBER         circ-reuse: Index (base 1) of OLdest (init 0)
RSILW       NUMBER         circ-reuse: Index of Last Written    (init 0)
RSRLW       NUMBER         circ-reuse: Recid of Last Written    (init 0)
non-circ-reuse: incr'd by kccicr()   (init 0)

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