11gr2 dbwr写入慢,redo log 大量active

环境：
OS : AIX 6.1
Oracle ：Oracle 11.2.0.3 with ASM
硬件:
Server : IBM P730 16C64G
Storage ：IBM V7000 : raid5
有16组logfile group，每个redolog file 5G，运行一段时间后（大概20多个小时），发现除了current的以外，其他的状态都是active。此时系统非常慢
alert log里面有提示:
Private strand flush not complete
Current log# 1 seq# 24288 mem# 0: +data/xxxxxxx/redo01_01.log
db_writer_processes 参数是 8
目前看存储的IO性能不是很好。
大家有什么好的建议吗？

请把alert.log 和最近的AWR发给我
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Thanks
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Hi
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Archive all the active online redo logs

Hi,
in 9.2.0 and in archivelog mode, how can I archive all the active online redo logs ?
Thank you.

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How to know the delay in redo log apply on Active Dataguard 11g

Hello All,
How to know the delay in redo log apply on Active Dataguard 11g...
Do we need to wait till log switch occurs?
Or is it recommended to schedule a log switch every 15 min, no matter data is updated/inserted or not in primary?
Please suggest...
Oracle : oracle 11g Release 2
OS : RHEL 5.4
Thanks
Edited by: user1687821 on Feb 23, 2012 12:02 AM

Hello CKPT,
Thank you for the valuable information...
We have not configured databroker.
Output of the query
SELECT * FROM (
SELECT sequence#, archived, applied,
TO_CHAR(completion_time, 'RRRR/MM/DD HH24:MI') AS completed
FROM sys.v$archived_log
ORDER BY sequence# DESC)
WHERE ROWNUM <= 10
Primary...
SEQUENCE#     ARCHIVED     APPLIED     COMPLETED
29680          YES          YES     2012/02/23 01:11
29680          YES          NO     2012/02/23 01:11
29679          YES          NO     2012/02/22 23:11
29679          YES          YES     2012/02/22 23:11
29678          YES          YES     2012/02/22 23:11
29678          YES          NO     2012/02/22 23:11
29677          YES          YES     2012/02/22 22:32
29677          YES          NO     2012/02/22 22:32
29676          YES          YES     2012/02/22 22:02
29676          YES          NO     2012/02/22 22:02
Standby...
SEQUENCE# ARC APP COMPLETED
29680 YES YES 2012/02/23 01:11
29679 YES YES 2012/02/22 23:11
29678 YES YES 2012/02/22 23:11
29677 YES YES 2012/02/22 22:32
29676 YES YES 2012/02/22 22:02
29675 YES YES 2012/02/22 21:24
29674 YES YES 2012/02/22 19:24
29673 YES YES 2012/02/22 18:59
29672 YES YES 2012/02/22 17:42
29671 YES YES 2012/02/22 17:41
Primary shows yes as well as no...
Next,
From primary:-
SQL> select thread#,max(sequence#) from v$archived_log group by thread#;
THREAD#     MAX(SEQUENCE#)
1     29680
From standby:-
SQL> select thread#,max(sequence#) from v$archived_log where applied='YES' group by thread#;
THREAD# MAX(SEQUENCE#)
1 29680
What is the redo transport service you are using? is it LGWR or ARCH ?
Output of query select * from v$parameter where name like 'log_archive_dest_2' shows below value...
SERVICE=b_stdb LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=b_stdb
So is it lgwr already configured...? if yes then how do i see the delay in both servers..
Yes, the network is good as they both resides in same LAN within same rack
Thanks...

Open database if an active online redo log is missing

Hi,
Sorry for the rather long post, but I specified all the steps I performed and couldn't make it shorter :-(
I need an advice on how to open the database if an active online redo log is missing.
For test purposes I intentionally performed a shutdown abort when the redo log group 1 was in active state and then renamed its only member (REDO01.LOG) so that the database couldn't perform crash recovery using it. Then upon startup I obviously got the message:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: 'H:\ORADATA\TESTDB\REDO01.LOG'
ORA-27041: unable to open file
OSD-04002: unable to open file
O/S-Error: (OS 2) The system cannot find the file specified.Ok, so I checked the state of the logs:
{noformat}
SQL>SELECT a.GROUP#, first_change#, SEQUENCE#, a.status, SUBSTR(b.MEMBER, 1, 40) MEMBER, b.status mem_status, a.archived
2    FROM v$log a, v$logfile b
3   WHERE a.GROUP# = b.GROUP#
4 ORDER BY a.GROUP#, b.MEMBER;
GROUP# FIRST_CHANGE# SEQUENCE# STATUS           MEMBER                         MEM_STA ARC
     1        592134         29 ACTIVE           H:\ORADATA\TESTDB\REDO01.LOG           YES
     2        592268         30 CURRENT          C:\ORADATA\TESTDB\REDO02.LOG           NO
     3        592129         28 ACTIVE           C:\ORADATA\TESTDB\REDO03.LOG           YES
{noformat}Since opening the database to perform a log switch and thus change the status of the redo log group 1 from ACTIVE to INACTIVE to recreate the member isn't possible, I performed database recovery.
SQL>recover database until cancel;
ORA-00279: change 592129 generated at 02/04/2009 10:31:15 needed for thread 1
ORA-00289: suggestion : C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_28_%U_.ARC
ORA-00280: change 592129 for thread 1 is in sequence #28
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
ORA-00279: change 592134 generated at 02/04/2009 10:31:28 needed for thread 1
ORA-00289: suggestion : C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_29_%U_.ARC
ORA-00280: change 592134 for thread 1 is in sequence #29
ORA-00278: log file 'C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_28_4RLR3JS9_.ARC' no longer needed for this rec
overy
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
'C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_29_4RLR4MF3_.ARC'
ORA-00279: change 592268 generated at 02/04/2009 10:32:03 needed for thread 1
ORA-00289: suggestion : C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_30_%U_.ARC
ORA-00280: change 592268 for thread 1 is in sequence #30
ORA-00278: log file 'C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_29_4RLR4MF3_.ARC' no longer needed for this rec
overy
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
'C:\ORADATA\TESTDB\REDO02.LOG'
Log applied.
Media recovery complete.
SQL>So for log sequence #28 I accepted the proposed archived redo log in the FRA, for sequence #29 (that's the online redo log that is missing!) I manually specified its archived copy, and for sequence #30 I specified the CURRENT online redo log. And as it seems the media recovery was successful.
Next I tried to open the database but again got the error:
SQL>alter database open noresetlogs;
alter database open noresetlogs
ERROR at line 1:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: 'H:\ORADATA\TESTDB\REDO01.LOG'
ORA-27041: unable to open file
OSD-04002: unable to open file
O/S-Error: (OS 2) The system cannot find the file specified.
The status of the log groups and its members is exactly as it was in the first query I wrote above, i.e. the redo log group 1 is still ACTIVE, so it's needed for crash recovery (which I had already done manually if I understand correctly how Oracle works!). I also checked if the datafiles are inconsistent (described in metalink doc id 1015544.102):
SQL>SELECT DISTINCT CHECKPOINT_CHANGE#, FUZZY FROM V$DATAFILE_HEADER;
CHECKPOINT_CHANGE# FUZ
            592269 NOSo, everything seems ok as far as datafile consistency is concerned.
My question is: how can I rename/drop/clear/whatever the member of redo log group 1 to open the database?
I tried to rename the log file member, to add another member to it, to open the database with resetlogs, to clear the logfile group 1, but all without success:
1)
SQL>alter database clear logfile group 1;
alter database clear logfile group 1
ERROR at line 1:
ORA-01624: log 1 needed for crash recovery of instance testdb (thread 1)
ORA-00312: online log 1 thread 1: 'H:\ORADATA\TESTDB\REDO01.LOG'
2)
SQL>alter database open resetlogs;
alter database open resetlogs
ERROR at line 1:
ORA-01139: RESETLOGS option only valid after an incomplete database recovery
3)
SQL>alter database rename file 'H:\ORADATA\TESTDB\REDO01.LOG' to 'C:\ORADATA\TESTDB\REDO01.LOG';
alter database rename file 'H:\ORADATA\TESTDB\REDO01.LOG' to 'C:\ORADATA\TESTDB\REDO01.LOG'
ERROR at line 1:
ORA-01511: error in renaming log/data files
ORA-01512: error renaming log file H:\ORADATA\TESTDB\REDO01.LOG - new file C:\ORADATA\TESTDB\REDO01.LOG not found
ORA-27041: unable to open file
OSD-04002: unable to open file
O/S-Error: (OS 2) The system cannot find the file specified.
4)
SQL>alter database add logfile member 'C:\ORADATA\TESTDB\REDO01.LOG' to group 1;
alter database add logfile member 'C:\ORADATA\TESTDB\REDO01.LOG' to group 1
ERROR at line 1:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: 'H:\ORADATA\TESTDB\REDO01.LOG'
ORA-27041: unable to open file
OSD-04002: unable to open file
O/S-Error: (OS 2) The system cannot find the file specified.Sorry again for the long post and thank you in advance for any suggestion.
Regards,
Jure

You could check if the recovery was complete by (re)creating the controlfile with the resetlogs option.
<CREATE CONTROLFILE REUSE DATABASE define_db_name RESETLOGS NOARCHIVELOG
...>Thanks for the hint. If possible, could you only check if the steps I'm going to perform are ok.
I did an "alter database backup controlfile to trace;" and then extracted the create controlfile definition part. So in essence I should run the following statements:
CREATE CONTROLFILE REUSE DATABASE "TESTDB" RESETLOGS ARCHIVELOG
    MAXLOGFILES 16
    MAXLOGMEMBERS 3
    MAXDATAFILES 100
    MAXINSTANCES 8
    MAXLOGHISTORY 292
LOGFILE
GROUP 1 'C:\ORADATA\TESTDB\REDO01.LOG' SIZE 20M,
GROUP 2 'C:\ORADATA\TESTDB\REDO02.LOG' SIZE 20M,
GROUP 3 'C:\ORADATA\TESTDB\REDO03.LOG' SIZE 20M
-- STANDBY LOGFILE
DATAFILE
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\SYSTEM01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\UNDOTBS01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\SYSAUX01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\USERS01.DBF'
CHARACTER SET EE8MSWIN1250
ALTER DATABASE OPEN RESETLOGS;
ALTER TABLESPACE TEMP ADD TEMPFILE 'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\TEMP01.DBF' REUSE;Is that correct?
About the RMAN backups: Wouldn't a 'CATALOG RECOVERY AREA' populate the controlfile with backup information again (I'm not using a recovery catalog in this case)?
Thanks for the help!
Regards,
Jure

When occurs crash recovery,why use active online redo log not archived log?

If current redo log had archived, but it's still 'ACTIVE'. As we all know, archived log is just an archived copy of the current redo log which is still 'ACTIVE', they have the same data. But why use active online redo log not archived log for crash recovery?(I think, if crash recovery can use archived log, then whether the online redo log is 'ACTIVE' or not, it can be overwritten)
Quote:
Re: v$log : How redo log file can have a status ACTIVE and be already archived?
Hemant K Chitale
If your instance crashes, Oracle attempts Instance Recovery -- reading from the Online Redo Logs. It doesn't need ArchiveLogs for Instance Recovery.
TanelPoder
Whether the log is already archived or not doesn't matter here, when the instance crashes, Oracle needs some blocks from that redolog. Archivelog is just an archived copy of the redolog, so you could use either the online or achive log for the recovery, it's the same data in there (Oracle reads the log/archivelog file header when it tries to use it for recovery and validates whether it contains the changes (RBA range) in it what it needs).

Aman.... wrote:
John,
Are you sure that the instance recovery (not the media recovery) would be using the archived redo logs? Since the only thing that would be lost is the isntance, there wouldn't be any archived redo log generated from the Current redo log and the previous archived redo logs, would be already checkpointed to the data file, IMHO archived redo logs won't participate in the instance recovery process. Yep, shall watch the video but tomorrow .
Regards
Aman....
That's what I said. Or meant to say. If Oracle used archivelogs for instance recovery, it would not be possible to recover in noarchive log mode. So recovery relies exclusively on the online log.
Sorry I wasted your time, I'll try to be less ambiguous in future

All redo log groups is active

Hello dear gurus!
After shutting database with option "abort"
we have unconsisten state of datafiles.
I ask to explain :
1) - does the ARCH background processes flash whole redo buffer into redolog ?
(In other words how reached consistency if all redo log groups was in active state before shutting down ?)
2) Where buffer contents in this case are dumped ?
Thanks and best regards,
Pavel
Edited by: Pavel on Jul 19, 2012 9:49 PM

Pavel wrote:
Hello dear gurus!
After shutting database with option "abort"
we have unconsisten state of datafiles.That's expected as checkpoint didn't happen. Issue a startup and instance recovery should take care of everything.
I ask to explain :
1) - does the ARCH background processes flash whole redo buffer into redolog ?ARCH process or LGWR? How does this relates to your current question?
(In other words how reached consistency if all redo log groups was in active state before shutting down ?)As I said, issue a startup of the instance and it should take care of the things.
2) Where buffer contents in this case are dumped ?Which case? Your questions are a bit fuzzy you see. Let's stick to one question at one time and follow it shall we?
Aman....

All Redo Log groups are active.

Hi All,
In one of our production database now a days we are seeing that all redo logs become active and then everything just get hang. It happens for 15-20 minutes and after that they come normal. Database size is over 4.5 TB and it's OLTP cum MIS database. As per Unix Team at server and storage level everything is fine so what could be other reason for this?
Database version is 9.2.0.5 and O/S is AIX 5.3 Power System.
select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIME
1 1 435847 1,342,177,280 2 YES ACTIVE 1.1782E+13 13-MAR-10
2 1 435848 1,342,177,280 2 YES ACTIVE 1.1782E+13 13-MAR-10
3 1 435850 1,342,177,280 2 NO CURRENT 1.1782E+13 13-MAR-10
4 1 435844 1,342,177,280 2 YES ACTIVE 1.1782E+13 13-MAR-10
5 1 435845 1,342,177,280 2 YES ACTIVE 1.1782E+13 13-MAR-10
6 1 435846 1,342,177,280 2 YES ACTIVE 1.1782E+13 13-MAR-10
7 1 435843 1,342,177,280 2 YES ACTIVE 1.1782E+13 13-MAR-10
8 1 435849 1,342,177,280 2 YES ACTIVE 1.1782E+13 13-MAR-10
9 1 435842 1,342,177,280 2 YES INACTIVE 1.1782E+13 13-MAR-10
9 rows selected.
VMSTAT output:
vmstat 2 10
kthr memory page faults cpu
r b avm fre re pi po fr sr cy in sy cs us sy id wa
35 13 23262385 48530 0 0 0 0 0 0 27910 531516 111964 54 7 12 26
30 12 23270696 26769 0 0 0 4277 19644 0 28759 604423 106619 53 7 14 25
26 12 23269357 25691 0 0 0 8899 38750 0 28620 552550 103736 55 7 15 23
32 14 23263410 31111 0 0 0 10778 47248 0 29722 690889 112674 53 7 16 24
27 17 23268835 25011 0 0 0 10267 51727 0 30321 779933 116936 58 8 13 21
30 20 23274592 25181 0 0 0 13569 59742 0 28290 731707 109167 59 7 13 22
33 10 23280476 30823 0 0 0 15259 66334 0 28942 774600 107692 65 7 8 20
36 13 23280770 26040 0 0 0 7199 33048 0 29351 687375 98487 63 7 10 20
35 16 23277780 27758 0 0 0 7250 33003 0 30699 622788 97172 65 6 10 19
31 13 23277431 25107 0 0 0 8521 37996 0 29746 596172 89831 63 6 11 20
select event, count(*) from v$session_wait group by event order by 2;
EVENT COUNT(*)
PL/SQL lock timer 2
SQL*Net more data from client 2
jobq slave wait 3
direct path read 5
rdbms ipc message 8
enqueue 11
log file sync 11
db file parallel write 12
latch free 12
pipe get 22
PX Deq: Execution Msg 27
buffer busy waits 33
db file scattered read 39
db file sequential read 169
SQL*Net message from client 2120

Hi,
Complete output would be so long so just putting tail of that.
RECID STAMP
NAME
DEST_ID THREAD# SEQUENCE# RESETLOGS_CHANGE# RESETLOGS_TIME FIRST_CHANGE# FIRST_TIME NEXT_CHANGE# NEXT_TIME BLOCKS BLOCK_SIZE CREATOR REGISTR STA ARC APP DEL S COMPLETION_TIME
DIC DIC END BACKUP_COUNT ARCHIVAL_THREAD# ACTIVATION#
711558 713531894
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435868 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES YES NO A 13-MAR-10
NO NO NO 0 1 2142322718
711559 713531942
/arch/ora/prod/PRODDB_1_00135869.arc
1 1 435869 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711560 713531994
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435869 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES YES NO A 13-MAR-10
NO NO NO 0 1 2142322718
711561 713532090
/arch/ora/prod/PRODDB_1_00135870.arc
1 1 435870 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711562 713532149
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435870 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES YES NO A 13-MAR-10
NO NO NO 0 1 2142322718
711563 713532276
/arch/ora/prod/PRODDB_1_00135871.arc
1 1 435871 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711564 713532322
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435871 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES YES NO A 13-MAR-10
NO NO NO 0 1 2142322718
711565 713532449
/arch/ora/prod/PRODDB_1_00135872.arc
1 1 435872 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711566 713532506
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435872 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES YES NO A 13-MAR-10
NO NO NO 0 1 2142322718
711567 713532607
/arch/ora/prod/PRODDB_1_00135873.arc
1 1 435873 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711568 713532662
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435873 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES YES NO A 13-MAR-10
NO NO NO 0 1 2142322718
711569 713532773
/arch/ora/prod/PRODDB_1_00135874.arc
1 1 435874 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711570 713532832
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435874 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES YES NO A 13-MAR-10
NO NO NO 0 1 2142322718
711571 713532933
/arch/ora/prod/PRODDB_1_00135875.arc
1 1 435875 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711572 713532980
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435875 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES YES NO A 13-MAR-10
NO NO NO 0 1 2142322718
711573 713533101
/arch/ora/prod/PRODDB_1_00135876.arc
1 1 435876 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711574 713533178
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435876 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES YES NO A 13-MAR-10
NO NO NO 0 1 2142322718
711575 713533258
/arch/ora/prod/PRODDB_1_00135877.arc
1 1 435877 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711576 713533323
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435877 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES YES NO A 13-MAR-10
NO NO NO 0 1 2142322718
711577 713533366
/arch/ora/prod/PRODDB_1_00135878.arc
1 1 435878 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711578 713533419
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435878 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES YES NO A 13-MAR-10
NO NO NO 0 1 2142322718
711579 713533497
/arch/ora/prod/PRODDB_1_00135879.arc
1 1 435879 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711580 713533537
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435879 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711581 713533678
/arch/ora/prod/PRODDB_1_00135880.arc
1 1 435880 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711582 713533737
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435880 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711583 713533841
/arch/ora/prod/PRODDB_1_00135881.arc
1 1 435881 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711584 713533919
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435881 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711585 713533983
/arch/ora/prod/PRODDB_1_00135882.arc
1 1 435882 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH NO YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718
711586 713534050
(DESCRIPTION=(ADDRESS_LIST = (ADDRESS=(PROTOCOL=tcp)(HOST=ilerpstdby)(PORT=1540)))(CONNECT_DATA=(SID=ILPROD)(SERVER=DEDICATED)))
2 1 435882 8.6960E+12 24-SEP-03 1.1782E+13 13-MAR-10 1.1782E+13 13-MAR-10 2621438 512 ARCH ARCH YES YES NO NO A 13-MAR-10
NO NO NO 0 1 2142322718

10G redo log switchs with no activity

We have been testing 8i to 10G migrations and two things I have noticed that are different bwteeen the 2 databases are:
1) redo log switching occurring even though the database has no users and just sitting there. This is not happeniong in our 8i databases.
2) trace files of format instance_m001_ and instance_m000_ in ../bdump. Our 8i bdump's normally do not have trc files unless a problem occurs.
Is it normal for 10G to automatically switch redo logs with no activity and are these .trc files also normal? In general I get nervous with trc files. -quinn

Still haven't figured out the redo log switches, they seem to be slowing down, but the excess trace files are apparently cuased by a bug and can be fixed with Patch 3432729.

Upon commit, lgwr writes to redo logs but dbwr does not write to datafiles

Guys,
Upon issuing a commit statement, in which scenarios, the lgwr only writes to redo logs but the dbwr does not at all write to the datafiles?
Thanx.

The default behaviour is - on Commit, the lgwr writes to the redo logs immediately, but it may not get immediately written to the datafiles by the dbwr, but sooner or later it would (based on certain conditions). The only situation, which I can think of, when dbwr may not be able to write is datafiles is when the databases crashes, after the commit and before the DBWR could write to the datafiles.
Not sure, what you are exactly looking for, but hope this helps.
Thanks
Chandra Pabba

Filled redo log files are available to LGWR for reuse

Hi,
Oracle version:
Oracle Database 10g Release 10.2.0.4.0 -
OS:Windows XP
In oracle documentation it is mentioned that:
Filled redo log files are available to LGWR for reuse depending on whether archiving is enabled.
*> If archiving is disabled (the database is in NOARCHIVELOG mode), a filled redo log file is available after the changes recorded in it have been written to the datafiles*.
Link for Documentation is:
http://docs.oracle.com/cd/B28359_01/server.111/b28310/onlineredo001.htm
My doubt is:
Redo Records are written to datafiles also??

user12141893 wrote:
Does it mean:
Suppose:
Online redo log files contains some redo entries and database buffer cache contains some data and this data belong to redo entries of redo log files.
Now this redo log file can't be reused until those (related) blocks of database buffer cache are written into datafiles.
This is sort of correct. If the log file would be filled up , LGWR would switch over to the next log group and would initiate a Log Switch which would further trigger DBWR to start checkpointing the content protected by this log group to the data file. By the time this operation would be going on, the Log group's members would have the status of Active and once it would be complete, the status would be marked to Inactive which means that this log group and its members can be reused by LGWR.
HTH
Aman....

Doubts in Redo log

Hi,
DB: 10.2.0.4
OS: UNIX/Windows
I have some doubts in archive log generation.
*1)* Once current redo log is filed , LGWR will move to next redo log which is available with status INACTIVE , and current one will become ACTIVE.If more archive logs are generating , based on business , ACTIVE will become INACTIVE after sometime and can use for CURRENT redo log.
If no archive logs are generated , my redo log is not coming out from status ACTIVE to INACTIVE .Even i waited for 5 minutes , but i had the same status.
What will be the time to make ACTIVE to INACTIVE?. What causing to make this happen ?.
Normally , when checkpoint is happened DBWR will write the CURRENT log data to data files , right?.In ACTIVE state , has archive log generated?. Many times i seen archive log is generated even it is in ACTIVE state.
*2)* My Archive logs size (25MB) is not equal to the redo log size. Normally , when we switch the logs or any rman backup , logs will be switched automatically and how much redo is filled , same will be generated with size.
But, in my case , more archive logs are generating and many have the different size out of generated and no manual switching or rman script are running during this period.
Any idea on this?.
Thanks,
Sunand

sunand wrote:
Hi,
DB: 10.2.0.4
OS: UNIX/Windows
I have some doubts in archive log generation.
*1)* Once current redo log is filed , LGWR will move to next redo log which is available with status INACTIVE , and current one will become ACTIVE.If more archive logs are generating , based on business , ACTIVE will become INACTIVE after sometime and can use for CURRENT redo log.
If no archive logs are generated , my redo log is not coming out from status ACTIVE to INACTIVE .Even i waited for 5 minutes , but i had the same status.
What will be the time to make ACTIVE to INACTIVE?. What causing to make this happen ?.
Normally , when checkpoint is happened DBWR will write the CURRENT log data to data files , right?.In ACTIVE state , has archive log generated?. Many times i seen archive log is generated even it is in ACTIVE state.
That is wrong.DBWR process write dirty blocks from database buffer cache to datafiles but not "CURRENT log data to data files".So if your current online log group is full then ARCH process will try archiving this group to available destination and without archiving there will not happen LOG SWITCH.After archiving log switch will happen and LOG SEQUENCE NUMBER will increase then you will get new current log group.IF old group status is ACTIVE it means this group still need instance recovery.SO when you execute ALTER SYSTEM CHECKPOINT in this case status of this group will INACTIVE.
*2)* My Archive logs size (25MB) is not equal to the redo log size. Normally , when we switch the logs or any rman backup , logs will be switched automatically and how much redo is filled , same will be generated with size.
But, in my case , more archive logs are generating and many have the different size out of generated and no manual switching or rman script are running during this period.
Any idea on this?.
As you know archivelogs is a copy of online redologs,but there can be several reasons and result these size can be different.For example manual log switch or if you set ARCHIVE_LAG_TARGET != 0.Finally archive logs contains information for media recover,but online redo logs contain instance and media recovery it means these size can be different.

Redo log space requests VALUE high

SELECT name||' = '||value
FROM v$sysstat
WHERE name = 'redo log space requests';
I am noticing 40+ space requests for some of my Oracle 9.2.0.5 databases.
On another 7.3.4 DB I see this over 140 but this DB shutdown only on weekends so this cumulative value increases I presume.
I have 20MB of 5 groups already. Do I still add another 2 more groups or increase their sizes ?
I did read somewhere that I'd have to increase the log_buffer parameter. So how do we deal with this issue ? Any repercussions if I let this as it is for now ?
The cause of this would be redo logs are not big enough or otherwise ?
Thanks.

user4874781 wrote:
Thanks for your response Charles.
So if I understand this correctly ... Redolog Space requests corresponds to a either an incorrectly sized redo log file / DBWR / CKPT needs to be tuned.
Maybe I was interpreting this the wrong way. (Possibly)
" The statistic 'redo log space requests' reflects the number of times a user process waits for space in the redo log buffer. " If that is the case, if there was longer waits for this event, I was under the assumption that log_buffer needs to be increased.
http://www.idevelopment.info/data/Oracle/DBA_tips/Tuning/TUNING_6.shtml
* Yes, the waits have increased to 70 as of now (since 40 yesterday .. DB was started Saturday night and will run till weekend) Less activity as of now, since the day has just started ; so it would definitely rise by end of the day. I took a look at the above article, and I think I understand why the article is slightly confusing. With due respect to the author, the article was last modified 16-Apr-2001, which I believe is before the Oracle documentation was better clarified regarding these statistics. From:
http://download.oracle.com/docs/cd/B14117_01/server.101/b10755/stats002.htm
"redo log space requests: Number of times the active log file is full and Oracle must wait for disk space to be allocated for the redo log entries. Such space is created by performing a log switch. Log files that are small in relation to the size of the SGA or the commit rate of the work load can cause problems. When the log switch occurs, Oracle must ensure that all committed dirty buffers are written to disk before switching to a new log file. If you have a large SGA full of dirty buffers and small redo log files, a log switch must wait for DBWR to write dirty buffers to disk before continuing."
"redo log space wait time: Total elapsed waiting time for "redo log space requests" in 10s of milliseconds"
It is quite possible that the "redo log space requests" will increase with every redo log file switch, which should not be too much of a concern. You may want to focus a little more on the "redo log space wait time" statistic, which indicates how much wait time was involved waiting. You might also want to focus on the system-wide wait event interface, examining how the accumulated wait time increases from one sampling of each of the statistics to the next.
* I have 1 log switch every 11 minutes ; BTW ; I have 5 log groups of 20 MB each as of now. So I am assuming 40 MB of 4 or 5 log groups should be fine as per your suggestion ?If you have the disk space, considering that it is an ancient AIX box, you may want to set the redo log files to an even larger size, possibly 100MB (or larger). You may then want to force periodic switches of the redo log, for instance once an hour, or once every 30 minutes.
* This is an ancient AIX box with 512 MB Ram. Is the redo log located on a fast device ? I'd have to find that out ( any hints on that ? )
* Decreasing the log_buffer is possible on weekends since I'd have to bounce it for it to take effect.
I will increase the log files accordingly and hopefully the space waits will reduce. Thanks again.Someone else, possibly Sybrand, on the forums might be familiar with AIX and be able to provide you with an answer. If you are seeing system-wide increasing wait time for redo related waits, then that might be an indication that the redo logs are not located on a fast device.
Charles Hooper
IT Manager/Oracle DBA
K&M Machine-Fabricating, Inc.

Redo log space requests and Enqueue Waits

Hi all,
I am seeing an increase on the Enqueue Waits and Redo Log Space Request from 58, 274 to 192, 1245 in two weeks time respectively.
The DB is a production database and runs on an HP cluster with 4X1G ram and 550mghz cpu.
There are four Redo Log files with 200M (2 members each)which I have increased to 400M over this past weekend.
I have included below the memory structure details:
Redo Log Summary
Total System Global Area 1646094824 bytes
Fixed Size 104936 bytes
Variable Size 408989696 bytes
Database Buffers 1228800000 bytes
Redo Buffers 8200192 bytes
My question is that, who do I stop it from growing further and passing the 1:5000 ratio ?
At the moment the ratio is in the range of 1:186194.
Your input is much appreciated.
Cheers,
Seyoum.

Here is some information from Oracle's Peformance Tuning Guide.
The V$SYSSTAT statistic redo log space requests indicates how many times a server process had to wait for space in the online redo log, not for space in the redo log buffer. A significant value for this statistic and the wait events should be used as an indication that checkpoints, DBWR, or archiver activity should be tuned, not LGWR. Increasing the size of log buffer does not help.

11gr2 dbwr写入慢,redo log 大量active

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