Redolog switching

Hi Friends,
Thread 1 advanced to log sequence 30609
Current log# 2 seq# 30609 mem# 0: /oradata/dbfiles/ORCL/redo02.log
Current log# 2 seq# 30609 mem# 1: /oradata/dbfiles/ORCL/redo05.log
Current log# 2 seq# 30609 mem# 2: /oradata/dbfiles/ORCL/redo08.log
Sun Nov 11 05:27:31 2007
Thread 1 cannot allocate new log, sequence 30610
Checkpoint not complete
Current log# 2 seq# 30609 mem# 0: /oradata/dbfiles/ORCL/redo02.log
Current log# 2 seq# 30609 mem# 1: /oradata/dbfiles/ORCL/redo05.log
Current log# 2 seq# 30609 mem# 2: /oradata/dbfiles/ORCL/redo08.log
Thread 1 advanced to log sequence 30610
Current log# 3 seq# 30610 mem# 0: /oradata/dbfiles/ORCL/redo03.log
Current log# 3 seq# 30610 mem# 1: /oradata/dbfiles/ORCL/redo06.log
Current log# 3 seq# 30610 mem# 2: /oradata/dbfiles/ORCL/redo09.log
Sun Nov 11 05:27:50 2007
Thread 1 cannot allocate new log, sequence 30611
Checkpoint not complete
Current log# 3 seq# 30610 mem# 0: /oradata/dbfiles/ORCL/redo03.log
Current log# 3 seq# 30610 mem# 1: /oradata/dbfiles/ORCL/redo06.log
Current log# 3 seq# 30610 mem# 2: /oradata/dbfiles/ORCL/redo09.log
Thread 1 advanced to log sequence 30611
Current log# 1 seq# 30611 mem# 0: /oradata/dbfiles/ORCL/redo01.log
Current log# 1 seq# 30611 mem# 1: /oradata/dbfiles/ORCL/redo04.log
Current log# 1 seq# 30611 mem# 2: /oradata/dbfiles/ORCL/redo07.log
Sun Nov 11 05:28:11 2007
Thread 1 advanced to log sequence 30612
Current log# 2 seq# 30612 mem# 0: /oradata/dbfiles/ORCL/redo02.log
Current log# 2 seq# 30612 mem# 1: /oradata/dbfiles/ORCL/redo05.log
Current log# 2 seq# 30612 mem# 2: /oradata/dbfiles/ORCL/redo08.log
Sun Nov 11 05:28:23 2007
Thread 1 cannot allocate new log, sequence 30613
Checkpoint not complete
Current log# 2 seq# 30612 mem# 0: /oradata/dbfiles/ORCL/redo02.log
Current log# 2 seq# 30612 mem# 1: /oradata/dbfiles/ORCL/redo05.log
Current log# 2 seq# 30612 mem# 2: /oradata/dbfiles/ORCL/redo08.log
Thread 1 advanced to log sequence 30613
Current log# 3 seq# 30613 mem# 0: /oradata/dbfiles/ORCL/redo03.log
Current log# 3 seq# 30613 mem# 1: /oradata/dbfiles/ORCL/redo06.log
Current log# 3 seq# 30613 mem# 2: /oradata/dbfiles/ORCL/redo09.log
Sun Nov 11 05:28:44 2007
Thread 1 advanced to log sequence 30614
Current log# 1 seq# 30614 mem# 0: /oradata/dbfiles/ORCL/redo01.log
Current log# 1 seq# 30614 mem# 1: /oradata/dbfiles/ORCL/redo04.log
Current log# 1 seq# 30614 mem# 2: /oradata/dbfiles/ORCL/redo07.log
Sun Nov 11 05:29:00 2007
Thread 1 cannot allocate new log, sequence 30615
Checkpoint not complete
Current log# 1 seq# 30614 mem# 0: /oradata/dbfiles/ORCL/redo01.log
Current log# 1 seq# 30614 mem# 1: /oradata/dbfiles/ORCL/redo04.log
Current log# 1 seq# 30614 mem# 2: /oradata/dbfiles/ORCL/redo07.log
Thread 1 advanced to log sequence 30615
Current log# 2 seq# 30615 mem# 0: /oradata/dbfiles/ORCL/redo02.log
Current log# 2 seq# 30615 mem# 1: /oradata/dbfiles/ORCL/redo05.log
Current log# 2 seq# 30615 mem# 2: /oradata/dbfiles/ORCL/redo08.log
Sun Nov 11 05:29:19 2007
Thread 1 cannot allocate new log, sequence 30616
Checkpoint not complete
Current log# 2 seq# 30615 mem# 0: /oradata/dbfiles/ORCL/redo02.log
Current log# 2 seq# 30615 mem# 1: /oradata/dbfiles/ORCL/redo05.log
Current log# 2 seq# 30615 mem# 2: /oradata/dbfiles/ORCL/redo08.log
Thread 1 advanced to log sequence 30616
Current log# 3 seq# 30616 mem# 0: /oradata/dbfiles/ORCL/redo03.log
Current log# 3 seq# 30616 mem# 1: /oradata/dbfiles/ORCL/redo06.log
Current log# 3 seq# 30616 mem# 2: /oradata/dbfiles/ORCL/redo09.log
Sun Nov 11 05:29:40 2007
Thread 1 cannot allocate new log, sequence 30617
Checkpoint not complete
Current log# 3 seq# 30616 mem# 0: /oradata/dbfiles/ORCL/redo03.log
Current log# 3 seq# 30616 mem# 1: /oradata/dbfiles/ORCL/redo06.log
Current log# 3 seq# 30616 mem# 2: /oradata/dbfiles/ORCL/redo09.log
Thread 1 advanced to log sequence 30617
Current log# 1 seq# 30617 mem# 0: /oradata/dbfiles/ORCL/redo01.log
Current log# 1 seq# 30617 mem# 1: /oradata/dbfiles/ORCL/redo04.log
Current log# 1 seq# 30617 mem# 2: /oradata/dbfiles/ORCL/redo07.log
Sun Nov 11 05:29:58 2007
Thread 1 cannot allocate new log, sequence 30618
Checkpoint not complete
Current log# 1 seq# 30617 mem# 0: /oradata/dbfiles/ORCL/redo01.log
Current log# 1 seq# 30617 mem# 1: /oradata/dbfiles/ORCL/redo04.log
Current log# 1 seq# 30617 mem# 2: /oradata/dbfiles/ORCL/redo07.log
Thread 1 advanced to log sequence 30618
Current log# 2 seq# 30618 mem# 0: /oradata/dbfiles/ORCL/redo02.log
Current log# 2 seq# 30618 mem# 1: /oradata/dbfiles/ORCL/redo05.log
Current log# 2 seq# 30618 mem# 2: /oradata/dbfiles/ORCL/redo08.log
Sun Nov 11 05:30:20 2007
Thread 1 advanced to log sequence 30619
Current log# 3 seq# 30619 mem# 0: /oradata/dbfiles/ORCL/redo03.log
Current log# 3 seq# 30619 mem# 1: /oradata/dbfiles/ORCL/redo06.log
Current log# 3 seq# 30619 mem# 2: /oradata/dbfiles/ORCL/redo09.log
Sun Nov 11 05:30:33 2007
Thread 1 cannot allocate new log, sequence 30620
Checkpoint not complete
Current log# 3 seq# 30619 mem# 0: /oradata/dbfiles/ORCL/redo03.log
Current log# 3 seq# 30619 mem# 1: /oradata/dbfiles/ORCL/redo06.log
Current log# 3 seq# 30619 mem# 2: /oradata/dbfiles/ORCL/redo09.log
Thread 1 advanced to log sequence 30620
Current log# 1 seq# 30620 mem# 0: /oradata/dbfiles/ORCL/redo01.log
Current log# 1 seq# 30620 mem# 1: /oradata/dbfiles/ORCL/redo04.log
Current log# 1 seq# 30620 mem# 2: /oradata/dbfiles/ORCL/redo07.log
Sun Nov 11 05:30:56 2007
Thread 1 advanced to log sequence 30621
Current log# 2 seq# 30621 mem# 0: /oradata/dbfiles/ORCL/redo02.log
Current log# 2 seq# 30621 mem# 1: /oradata/dbfiles/ORCL/redo05.log
Current log# 2 seq# 30621 mem# 2: /oradata/dbfiles/ORCL/redo08.log
Sun Nov 11 05:31:07 2007
Thread 1 cannot allocate new log, sequence 30622
Checkpoint not complete
Current log# 2 seq# 30621 mem# 0: /oradata/dbfiles/ORCL/redo02.log
Current log# 2 seq# 30621 mem# 1: /oradata/dbfiles/ORCL/redo05.log
Current log# 2 seq# 30621 mem# 2: /oradata/dbfiles/ORCL/redo08.log
Thread 1 advanced to log sequence 30622
Current log# 3 seq# 30622 mem# 0: /oradata/dbfiles/ORCL/redo03.log
Current log# 3 seq# 30622 mem# 1: /oradata/dbfiles/ORCL/redo06.log
Current log# 3 seq# 30622 mem# 2: /oradata/dbfiles/ORCL/redo09.log
Sun Nov 11 05:31:28 2007
Thread 1 advanced to log sequence 30623
Current log# 1 seq# 30623 mem# 0: /oradata/dbfiles/ORCL/redo01.log
Current log# 1 seq# 30623 mem# 1: /oradata/dbfiles/ORCL/redo04.log
Current log# 1 seq# 30623 mem# 2: /oradata/dbfiles/ORCL/redo07.log
Sun Nov 11 05:31:40 2007
Thread 1 cannot allocate new log, sequence 30624
Checkpoint not complete
Current log# 1 seq# 30623 mem# 0: /oradata/dbfiles/ORCL/redo01.log
Current log# 1 seq# 30623 mem# 1: /oradata/dbfiles/ORCL/redo04.log
Current log# 1 seq# 30623 mem# 2: /oradata/dbfiles/ORCL/redo07.log
Thread 1 advanced to log sequence 30624
Current log# 2 seq# 30624 mem# 0: /oradata/dbfiles/ORCL/redo02.log
Current log# 2 seq# 30624 mem# 1: /oradata/dbfiles/ORCL/redo05.log
Current log# 2 seq# 30624 mem# 2: /oradata/dbfiles/ORCL/redo08.log
Sun Nov 11 06:21:18 2007
Thread 1 advanced to log sequence 30625
Current log# 3 seq# 30625 mem# 0: /oradata/dbfiles/ORCL/redo03.log
Current log# 3 seq# 30625 mem# 1: /oradata/dbfiles/ORCL/redo06.log
Current log# 3 seq# 30625 mem# 2: /oradata/dbfiles/ORCL/redo09.log
Sun Nov 11 08:26:01 2007
Thread 1 advanced to log sequence 30626
Current log# 1 seq# 30626 mem# 0: /oradata/dbfiles/ORCL/redo01.log
Current log# 1 seq# 30626 mem# 1: /oradata/dbfiles/ORCL/redo04.log
Current log# 1 seq# 30626 mem# 2: /oradata/dbfiles/ORCL/redo07.log
Sun Nov 11 10:00:26 2007
Thread 1 advanced to log sequence 30627
Current log# 2 seq# 30627 mem# 0: /oradata/dbfiles/ORCL/redo02.log
Current log# 2 seq# 30627 mem# 1: /oradata/dbfiles/ORCL/redo05.log
Current log# 2 seq# 30627 mem# 2: /oradata/dbfiles/ORCL/redo08.log
Sun Nov 11 11:40:47 2007
Thread 1 advanced to log sequence 30628
Current log# 3 seq# 30628 mem# 0: /oradata/dbfiles/ORCL/redo03.log
Current log# 3 seq# 30628 mem# 1: /oradata/dbfiles/ORCL/redo06.log
Current log# 3 seq# 30628 mem# 2: /oradata/dbfiles/ORCL/redo09.log
My alert log shows, there is no fixed time for log switch..once it will do by 1, 2 mins..once it does by one hour ..once it does by 30mins....why this behaviour???..mine is 10.2.0.1 with 8MB log file size with 3 redolog groups in archive log mode...
these are the related parameters
fast_start_mttr_target = 0
log_checkpoint_interval = 0
log_checkpoint_time_out = 1800
I can increase the redo log file size....but what my doubt is some times, it is going to switch by 30min or 1 hour, so..why is it happening....

Hi Bogey,
I guess there is some confusion some where.I didnt use much technical terms reading that you came from a different db.Anyways not an issue.
if you do not archive for lets say 5 hrs, this is letting your redo switch when it wants to and you have a disaster on your prod machine then the best you can do to recover is from your last archive log which would be 5hrs
I didnt get this.I guess you mean to say that if we dont control log switch and than it happens on its own than we have a recovery issue in case of a disaster.correct me where I am wrong.
--Would it not be a good practice to set a time for your redo log switch
Yes it will be.What we mean by having the log switch is that our data which is changed aka Dirty buffers is saved in the data files.This is to protect our work replay when we will encounter any failures in our database.Yes it willbe a good thing to control the timing of redo log switching.The reasoning for that is the smallest time we have the less we lose in case of the coplete crash.But with very frequent checkpointing the writing ios of database will go mad.And this will choke up the database very soon.The point is we dont want to choke up our media and writing ios plus we want to lose minimum.thats why the "best practise" advice is given as that 20 minutes timing is the best for "most" databases.You may want to become more less than that or greater than that( as you are 8hours).But the point is being more is not good and also the size of the redo log files should be adeqaute enough to control this switch time.Now for that it is suggested that one should use the Redo Log File Size advisor.Now in case lets suppose you have been suggested by Oracle that you use redo log of 3gig, it may be take hours to get it filled, like for example,5 hours.Means our data of 5 hours is on the stake.So for that you can use the Archive_lag_target parameter which will swtich your redo log files at the desired frequency which you think is good and safe enough for you.Search out here for this parameter.HJR has given a very nice explanation of it.I guess that might be what you are looking for.
In your case,5 hours I think is a little too big time for switching.
Aman....

Similar Messages

REDOLOG FILL UP

Is it possible to check how much percentage or bytes of redolog is taken from latest switch operation,
sometimes is necessary to check when the next redolog switching operation will be execute

Not sure why you care about when you will get a log switch, but I found the following which may be what you want :-
select
le.leseq "Current log sequence No",
100*cp.cpodr_bno/le.lesiz "Percent Full",
cp.cpodr_bno "Current Block No",
le.lesiz "Size of Log in Blocks"
from
x$kcccp cp,
x$kccle le
where
LE.leseq =CP.cpodr_seq
and bitand(le.leflg,24)=8;
From :- http://www.adp-gmbh.ch/ora/misc/x.html

Real time apply dataguard

Hello
I have some doubts about real time apply.
If a transaction occurs in production, lgwr will automatically write this transaction to standby redologs in standby database.
Is this transaction applied to standby database immediately or wait for standby redolog switch and applied as soon as standby log is archived ?

Thanks Uwe.
Eventhough you mentioned this before, I just want to ask last time to confirm:
Regarding real time apply;
When a transaction occurs in production, this transaction is not applied directly to standby database.
It is first transferred to standby redolog( by the log writer of primary) and from there to standby database immediately. (I dont know which background proces is responsible for this)
Is this right?By default, the archives are transferred(on completion) to standby database server using ARCH process and received by Remote File Server process (RFS) on standby database server. Optionally, you may choose to do the same using standby redo logs instead of archive log files (LGWR and LNS processes comes into picture). The standby redo logs are compulsory for real time apply regardless of protection mode.
If you're using SRL, then redo data is transferred to SRL and once the SRL is archived the changes are written to the database using Managed Recovery Process (MRP) and hence minimizes the data loss in case of failover and minimizes the time in case of switchover and failover.
If you're using Real Time Apply, then the standby redo log data is directly written to the database using LSP or MRP without waiting for SRL to be archived.
Regards,
S.K.
Edited by: Santosh Kumar on Sep 22, 2009 3:53 PM

"Checkpoint not complete" hangs!

Hi everyone;
I see "Checkpoint not complete" in the alertlog but normally oracle just waits seconds then checkpoints and go on... But the problem is, database sometimes hangs with this message for minutes and never respond until i checkpoint manually.
I made the necessary changes to avoid "Checkpoint not complete" message. Number of Redolog groups was increased, redolog size was increased, 5 dbwr was configured.
But the real problem is not the message, oracle cannot go over this message and hangs!!
10.2.0.1.0 - on hp-ux 11.31
Thanks for your help...
Edited by: emre baransel on Sep 18, 2009 10:27 AM

emre baransel wrote:
Hi everyone;
I see "Checkpoint not complete" in the alertlog but normally oracle just waits seconds then checkpoints and go on... But the problem is, database sometimes hangs with this message for minutes and never respond until i checkpoint manually.Oracle hangs until released the checkpoint, this is an expected behaviour to be keep data consistency :
http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/waitevents003.htm#sthref3113
Please, check the alert log file to see the time between redolog switch. Check if you have not I/O slowness on your hard drive.
I would advise the reading of Metalink note
Checkpoint Tuning and Troubleshooting Guide*
Doc ID: 147468.1*
Nicolas.

Redo log swith check

How we can check the time or Redo log swith, how i can check how much time it takes to fill one log file

Hello,
I am not sure if the user originally wanted to dicuss performance aspect of redo-log switch. He was probably more interested in knowing what can influence redo-log switch.
The reason I am replying the the latest update, is to further add to what kmcswain has commented on this thread. Its really important how often redo-log switch takes place. Switching definately have overhead on the CPU and the disk i/o, but if you do-not switch too often, there are two main concerns
1. When switch would take place, it would require more resources, as the CPU/Disk i/o would go higher in comparision to switching more often
2. Archiving would not be done till the redolog switch takes place. So there are more chances of loosing data
What I have found more pratical is to see your average CPU and disk utilizations. If you have more CPU resources available and disk i/o contention is not there, having a big redo-log would not negatiely effect your db performance. If your CPU utlilzation has fluctuations, and peak reaches anything above 90%, then investigate the fluctuations by reducing the redolog size. The fluctuations should flaten
Hope that make sense
Cheers
Sudhanshu

Logswitch

Log switch is happening very frequently (log switches every two minutes)
Archivelog logs are filling very quickly
The below message found in the alert log:
ORACLE Instance prod1
Thread 1 cannot allocate new log, sequence 5012
All online logs needed archiving

Hi,
Examine the period where you are getting high redos generation and based on that schedule some jobs at a later point in time:
We can the log switch details with the help of the below query:
Redolog switch Datewise and hourwise:
set lines 120;
set pages 999;
select to_char(first_time,'DD-MON-RR') "Date",
to_char(sum(decode(to_char(first_time,'HH24'),'00',1,0)),'99') " 00",
to_char(sum(decode(to_char(first_time,'HH24'),'01',1,0)),'99') " 01",
to_char(sum(decode(to_char(first_time,'HH24'),'02',1,0)),'99') " 02",
to_char(sum(decode(to_char(first_time,'HH24'),'03',1,0)),'99') " 03",
to_char(sum(decode(to_char(first_time,'HH24'),'04',1,0)),'99') " 04",
to_char(sum(decode(to_char(first_time,'HH24'),'05',1,0)),'99') " 05",
to_char(sum(decode(to_char(first_time,'HH24'),'06',1,0)),'99') " 06",
to_char(sum(decode(to_char(first_time,'HH24'),'07',1,0)),'99') " 07",
to_char(sum(decode(to_char(first_time,'HH24'),'08',1,0)),'99') " 08",
to_char(sum(decode(to_char(first_time,'HH24'),'09',1,0)),'99') " 09",
to_char(sum(decode(to_char(first_time,'HH24'),'10',1,0)),'99') " 10",
to_char(sum(decode(to_char(first_time,'HH24'),'11',1,0)),'99') " 11",
to_char(sum(decode(to_char(first_time,'HH24'),'12',1,0)),'99') " 12",
to_char(sum(decode(to_char(first_time,'HH24'),'13',1,0)),'99') " 13",
to_char(sum(decode(to_char(first_time,'HH24'),'14',1,0)),'99') " 14",
to_char(sum(decode(to_char(first_time,'HH24'),'15',1,0)),'99') " 15",
to_char(sum(decode(to_char(first_time,'HH24'),'16',1,0)),'99') " 16",
to_char(sum(decode(to_char(first_time,'HH24'),'17',1,0)),'99') " 17",
to_char(sum(decode(to_char(first_time,'HH24'),'18',1,0)),'99') " 18",
to_char(sum(decode(to_char(first_time,'HH24'),'19',1,0)),'99') " 19",
to_char(sum(decode(to_char(first_time,'HH24'),'20',1,0)),'99') " 20",
to_char(sum(decode(to_char(first_time,'HH24'),'21',1,0)),'99') " 21",
to_char(sum(decode(to_char(first_time,'HH24'),'22',1,0)),'99') " 22",
to_char(sum(decode(to_char(first_time,'HH24'),'23',1,0)),'99') " 23"
from v$log_history
group by to_char(first_time,'DD-MON-RR')
order by 1
Best regards,
Rafi.
http://rafioracledba.blogspot.com

AWR & ADDR Report

Hi ,
any one know how we cane read AWR report any basedline to comper ?? below some resuilts how can we now it's good or not .
Finding 2: Commits and Rollbacks
Impact is .02 active sessions, 10.04% of total activity.
Waits on event "log file sync" while performing COMMIT and ROLLBACK operations
were consuming significant database time.
Recommendation 1: Application Analysis
Estimated benefit is .02 active sessions, 10.04% of total activity.
Action
Investigate application logic for possible reduction in the number of
COMMIT operations by increasing the size of transactions.
Rationale
The application was performing 683 transactions per minute with an
average redo size of 4638 bytes per transaction.

Hello,
A Log file sync occurs when a process waits for the LGWR to confirm that the their redo has been flushed from the redo log buffer to disk.
The most common causes for this are:
1. Slow I/O subsystem on the location where the Redo Log files are stored.
2. Execessive commits. (i.e. an application inserting a lot of rows and commiting after each one)
3. Excessive switches.
Log file parallel write is the event waited for the actual write operation that the LGWR is perfoming from the log buffer to the disk. You should compare your average MS of Log File Parallel Write to yoiur Log File Sync event, and see how much of the log file Sync is actually waited on I/O. If it is a big part, then check your devices for slow I/O, and/or concurrency.
Check how many redo log switch per hour you are doing, It's possible that the increased DML activity from your load test is provoking an increse in redo switch activity due to your redolog file size. A redolog switch, ideally should not occur more often than once every 15 minutes.
Lastly, check if your application is commiting too agressively. This is likely your case. This can be derived in your AWR through your user calls/ commit ratio. At your Instance Activity part of the report check for the statistics:
user calls
user commits
user rollbacks
And then do : user calls/(user commits+user rollbacks)
This value should above 20-25, if not, your application is commiting too frequently.

Concepts about Archieving process and Check point Background process

I am still going through Oracle Architecture and presently on the background oracle process. I got struck about the function of Checkpoint process and how archieving process occurs. Any inputs from my friends here will be highly appreciated.

916438 wrote:
I am still going through Oracle Architecture and presently on the background oracle process. I got struck about the function of Checkpoint process and how archieving process occurs. Any inputs from my friends here will be highly appreciated. Checkpoint is an act of cleaning the dirty blocks from buffer cache to disks in order to make fast recovery(if happens) if crash happens. Having said this, this process will make sure that oracle has to recovery minimum numbers of dirty block on instance recovery phase. So there is periodic flushing of dirty blocks from buffer cache to disks. In this periodic time CKPT process will post to DBWR process to write out the dirty blocks to disks. This is basically called the incremental checkpointing.
In incremental checkpointing oracle will keep the record of most oldest block in controlfile and from this block (which is also called RBA), oracle will start recovering dirty blocks.
There is also a full checkpoint in oracle which happen when redolog switch
Now coming to archiving: An archive log is a copy of redo log files, it includes the sequence number and redo entries. Whenever there is a log switch (redo log files gets filled in circular fashion), then arch process will start archive filled redo log file. So during this process arch process will read the filled redo log files and make the copy of it in archive file. LGWR cannot write this filled redo file until ans unless arch process completes copying of redolog entries to archive log file.
Archive log files are required for recovery if in future we wish to recover database during media/datafile/controlfile failure.
Also see
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:19311485023372 - Checkpoint explained
http://docs.oracle.com/cd/B19306_01/server.102/b14231/archredo.htm - Archives
Edited by: 909592 on Mar 25, 2012 5:34 PM

How to fix some of the errors - result from runing EMDIAG

I ran EMDIAG got errors from the result, I was able to address some; however, there were some I am not sure how to tackle them, is there any white paper for documentation on how to fix these errors? Below is what I have from the log:
101. Jobs without any valid executions: 21
105. Scheduled job Executions with no valid steps (4348291): 1
125. Active jobs without execution info: 10
700. Obsoleted target propagation jobs (3877267): 248
verifyLOADERS
verifyMETRICS
107. Metric dependencies without details (6336199): 1
700. Outstanding cleared metric errors (8211608): 4
703. Metric errors for active metrics on Physical Standby DB (4906453): 46
705. Obsoleted metric errors for Configuration metrics: 8
800. Cleared cluster repository metric failures (5218353): 9
verifyNOTIFICATIONS
703. Old expired notifications in the queue: 576
verifyPLUGINS
verifyPOLICIES
702. Obsoleted last violations for stateless metrics (6990199): 6
verifyPROVISIONING
verifyRCA
verifyREPORTS
verifyREPOSITORY
601. Database Timezone mismatch: 1
604. Too many redolog switches: 1
605. Metric delete enabled for deleting targets: 1
806. NLS message mismatches: 3
verifyROLES
verifyTARGETS
103. Targets with property errors: 38
132. Targets not uploading any data: 10
202. Databases without a configuration snapshot: 1
602. Groups without members: 25
Thanks,

Did you check: EMDiagkit - How to Use the Repository Diagnostics [ID 421563.1]
https://support.oracle.com/CSP/ui/flash.html#tab=KBHome%28page=KBHome&id=%28%29%29,%28page=KBNavigator&id=%28bmDocTitle=EMDiagkit%20%20-%20How%20to%20Use%20the%20Repository%20Diagnostics&bmDocDsrc=KB&bmDocType=TROUBLESHOOTING&bmDocID=421563.1&viewingMode=1143&from=BOOKMARK%29%29
regards
Rob

SAP GoLive : File System Response Times and Online Redologs design

Hello,
A SAP Going Live Verification session has just been performed on our SAP Production environnement.
SAP ECC6
Oracle 10.2.0.2
Solaris 10
As usual, we received database configuration instructions, but I'm a little bit skeptical about two of them :
1/
We have been told that our file system read response times "do not meet the standard requirements"
The following datafile has ben considered having a too high average read time per block.
File name -Blocks read - Avg. read time (ms) -Total read time per datafile (ms)
/oracle/PMA/sapdata5/sr3700_10/sr3700.data10 67534 23 1553282
I'm surprised that an average read time of 23ms is considered a high value. What are exactly those "standard requirements" ?
2/
We have been asked to increase the size of the online redo logs which are already quite large (54Mb).
Actually we have BW loading that generates "Chekpoint not comlete" message every night.
I've read in sap note 79341 that :
"The disadvantage of big redo log files is the lower checkpoint frequency and the longer time Oracle needs for an instance recovery."
Frankly, I have problems undertanding this sentence.
Frequent checkpoints means more redo log file switches, means more archive redo log files generated. right ?
But how is it that frequent chekpoints should decrease the time necessary for recovery ?
Thank you.
Any useful help would be appreciated.

Hello
>> I'm surprised that an average read time of 23ms is considered a high value. What are exactly those "standard requirements" ?
The recommended ("standard") values are published at the end of sapnote #322896.
23 ms seems really a little bit high to me - for example we have round about 4 to 6 ms on our productive system (with SAN storage).
>> Frequent checkpoints means more redo log file switches, means more archive redo log files generated. right?
Correct.
>> But how is it that frequent chekpoints should decrease the time necessary for recovery ?
A checkpoint is occured on every logswitch (of the online redologfiles). On a checkpoint event the following 3 things are happening in an oracle database:
Every dirty block in the buffer cache is written down to the datafiles
The latest SCN is written (updated) into the datafile header
The latest SCN is also written to the controlfiles
If your redologfiles are larger ... checkpoints are not happening so often and in this case the dirty buffers are not written down to the datafiles (in the case of no free space in the buffer cache is needed). So if your instance crashes you need to apply more redologs to the datafiles to be in a consistent state (roll forward). If you have smaller redologfiles more log switches are occured and so the SCNs in the data file headers (and the corresponding data) are closer to the newest SCN -> ergo the recovery is faster.
But this concept does not really fit the reality because of oracle implements some algorithm to reduce the workload for the DBWR in the case of a checkpoint.
There are also several parameters (depends on the oracle version) which control that a required recovery time is kept. (for example FAST_START_MTTR_TARGET)
Regards
Stefan

How can I determine the number and sizes of redologs?

Dear all,
How can I determine the number and sizes of redologs are sufficient to allow redo log switching while hot backup is in progress?
Please advice,
Amy

Two questions here - what the OP put as the subject title and what was asked in the thread, which are different questions.
I would interpret the question in the thread to mean "how to avoid hanging due to archiving waiting for a redo log group to become available." Alert log, wait events, and user complaints would be the source of information here.

Redologs in physical standby database

The MRP process is started and the standby database is physical standby, which is running under managed standby. My Question is as below
1. Under managed recovery mode do we require the redo logs created on the physical standby database.
2. How does oracle keep the database in sync when there are no redo logs are created on the standby database.

The output is as below
SQL> select status, pid, sequence# from v$managed_standby where process like 'MRP%';
STATUS PID SEQUENCE#
WAIT_FOR_GAP 29710 88576
SQL>
The contents of alertlog ; i Just restarted the managed recovery to capture the information
RFS[1]: Archived Log: '/u02/archive/1_88817_665420030.dbf'
Sun Apr 18 18:34:26 2010
RFS[2]: No standby redo logfiles created
RFS[2]: Archived Log: '/u02/archive/1_88818_665420030.dbf'
Sun Apr 18 18:44:26 2010
RFS[3]: No standby redo logfiles created
RFS[3]: Archived Log: '/u02/archive/1_88819_665420030.dbf'
Sun Apr 18 18:54:26 2010
RFS[4]: No standby redo logfiles created
RFS[4]: Archived Log: '/u02/archive/1_88820_665420030.dbf'
Sun Apr 18 18:56:32 2010
alter database recover managed standby database cancel
Sun Apr 18 18:56:50 2010
MRP0: Background Media Recovery cancelled with status 16037
Sun Apr 18 18:56:50 2010
Errors in file /opt/home/oracle/admin/rmdp3/bdump/rmdp3_mrp0_29710.trc:
ORA-16037: user requested cancel of managed recovery operation
Recovery interrupted!
Sun Apr 18 18:56:51 2010
Waiting for MRP0 pid 29710 to terminate
Sun Apr 18 18:56:51 2010
Errors in file /opt/home/oracle/admin/rmdp3/bdump/rmdp3_mrp0_29710.trc:
ORA-16037: user requested cancel of managed recovery operation
Sun Apr 18 18:56:51 2010
MRP0: Background Media Recovery process shutdown (rmdp3)
Sun Apr 18 18:56:52 2010
Managed Standby Recovery Canceled (rmdp3)
Completed: alter database recover managed standby database cancel
Sun Apr 18 18:57:19 2010
alter database recover managed standby database disconnect
from session
Sun Apr 18 18:57:19 2010
Attempt to start background Managed Standby Recovery process (rmdp3)
MRP0 started with pid=19, OS id=2123
Sun Apr 18 18:57:19 2010
MRP0: Background Managed Standby Recovery process started (rmdp3)
Managed Standby Recovery not using Real Time Apply
Sun Apr 18 18:57:24 2010
Errors in file /opt/home/oracle/admin/rmdp3/bdump/rmdp3_mrp0_2123.trc:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: '/u03/redologs/rmdp3/redo01.log'
ORA-27037: unable to obtain file status
SVR4 Error: 2: No such file or directory
Additional information: 3
Sun Apr 18 18:57:24 2010
Errors in file /opt/home/oracle/admin/rmdp3/bdump/rmdp3_mrp0_2123.trc:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: '/u03/redologs/rmdp3/redo01.log'
ORA-27037: unable to obtain file status
SVR4 Error: 2: No such file or directory
Additional information: 3
Clearing online redo logfile 1 /u03/redologs/rmdp3/redo01.log
Clearing online log 1 of thread 1 sequence number 88818
Sun Apr 18 18:57:24 2010
Errors in file /opt/home/oracle/admin/rmdp3/bdump/rmdp3_mrp0_2123.trc:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: '/u03/redologs/rmdp3/redo01.log'
ORA-27037: unable to obtain file status
SVR4 Error: 2: No such file or directory
Additional information: 3
Sun Apr 18 18:57:24 2010
Errors in file /opt/home/oracle/admin/rmdp3/bdump/rmdp3_mrp0_2123.trc:
ORA-19527: physical standby redo log must be renamed
ORA-00312: online log 1 thread 1: '/u03/redologs/rmdp3/redo01.log'
Clearing online redo logfile 1 complete
Media Recovery Waiting for thread 1 sequence 88576
Fetching gap sequence in thread 1, gap sequence 88576-88675
FAL[client]: Error fetching gap sequence, no FAL server specified
Sun Apr 18 18:57:25 2010
Completed: alter database recover managed standby database disconnect
from session
Sun Apr 18 18:57:54 2010
FAL[client]: Failed to request gap sequence
GAP - thread 1 sequence 88576-88675
DBID 440735188 branch 665420030
FAL[client]: All defined FAL servers have been attempted.
Check that the CONTROL_FILE_RECORD_KEEP_TIME initialization
parameter is defined to a value that is sufficiently large
enough to maintain adequate log switch information to resolve
archivelog gaps.
Edited by: user11982297 on Apr 18, 2010 10:58 AM

When are Redolog files reset to zero size? Manual reset possible?

As far as I know redolog files contain all stuff which is changed during operation of an Oracle database.
However I wonder if there are events when these files are AUTOMATICALLY reset to zero.
I guess it is when I do a full offline backup.
Is this correct?
Are there any other events when this happens automatically ?
How can I manually reset/initialize Redolog files to an empty state?
Peter

What did you mean empty redo logfile?
if you mean zero size on redolog files....
We can not reset redo log files to empty (zero).
I guess it is when I do a full offline backup.That mean your database offline... no operation, so no redo log generate. but not mean you can make redo log empty anyway...
If you mean redo log file no need for instance recovery.
redo log groups have "INACTIVE" status -> is no longer needed for instance recovery. It may be in use for media recovery. It might or might not be archived.
check from v$log
UNUSED - Online redo log has never been written to. This is the state of a redo log that was just added, or just after a RESETLOGS, when it is not the current redo log.
CURRENT - Current redo log. This implies that the redo log is active. The redo log could be open or closed.
ACTIVE - Log is active but is not the current log. It is needed for crash recovery. It may be in use for block recovery. It may or may not be archived.
CLEARING - Log is being re-created as an empty log after an ALTER DATABASE CLEAR LOGFILE statement. After the log is cleared, the status changes to UNUSED.
CLEARING_CURRENT - Current log is being cleared of a closed thread. The log can stay in this status if there is some failure in the switch such as an I/O error writing the new log header.
INACTIVE - Log is no longer needed for instance recovery. It may be in use for media recovery. It might or might not be archived.;)

Best practice online redologs redundant

Oracle dbs on Unix without ASM
Few DBs have only single oracle filesystem available on unix box & have only one online redolog file available, wondering what would be the best practice to redundant them?
I know if i have multiple oracle filesystems , i can spread them there. but with only one filesystem, i can create one more redolog and put on the same filesystem.

All right here is my researchwork on this topic, make me right if i miss something, its not RAC, just single instance dbs.
Advantages
Oracle recommends that you mutliplex the online redo log files, store members on separate disk drives, Even if all
copies of the redo log are on the same disk, the redundancy can help protect against I/O errors, file corruption, and
so on.
Disadvantages
Multiplex redo log files. the database must increase the amount of I/O that it performs. Depending on your
configuration, this may impact overall database performance.
Each member in a group must be exactly the same size.
select GROUP#, MEMBER from v$logfile;
select GROUP#, MEMBERS, STATUS , BYTES from v$log;
ALTER DATABASE ADD LOGFILE MEMBER '/oracle/dbs/log2b.rdo' TO GROUP 2;
alter system switch logfile; (few times to make sure all ok)
Backout plan
alter database drop logfile member '/wmbrktst/oradata/wmbrktst/redo01.log';

Standby database online redologs

1-)
I know that online redologs are not being used in physical standby database.
Suppose I created a physical standby database with standby redologs.
As far as I know online redologs are not used in standby database,(standby redologs are used)
However, when I check the status of the online redologs in standby database I see that:
"CLEARING_CURRENT" or "CLEARING".
Their status is also changing once log switch occurs in production.
Whats the reason for this and why does this status always change, if standby online redologs are not used, their status
should not change.
2-)
What would happen if I delete the online redolog of the standby database from the operating system?
Does the status again show: clearing,clearing current?

Standby online logs are not used, but they have status CLEARING in preparation for a possible switchover/failover. So they are ready to become very fast active online logs.
I would never delete any database files on OS level, although the standby online logs are not needed when the database runs in standby role, Oracle will complain about their missing. At least when you restart the standby.
Werner

Redolog switching

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