Events of waiting "log file parallel write" / "log file sync", in CREATE INDEX

Similar Questions

• "redo the write time" includes "log file parallel write".

  IO performance Guru Christian said in his blog:
  
  http://christianbilien.WordPress.com/2008/02/12/the-%E2%80%9Clog-file-sync%E2%80%9D-wait-event-is-not-always-spent-waiting-for-an-IO/
  
  Waiting for synchronization of log file can be divided into:
  1. the 'writing time again': this is the total elapsed time of the writing of the redo log buffer in the log during recovery (in centisecondes).
  2. the 'parallel log writing' is actually the time for the e/s of journal writing complete
  3. the LGWR may have some post processing to do, signals, then the foreground process on hold that Scripture is complete. The foreground process is finally awake upward by the dispatcher of system. This completes pending "journal of file synchronization.
  
  In his mind, there is no overlap between "redo write time" and "log file parallel write.
  
  But in the metalink 34592.1:
  
  Waiting for synchronization of log file may be broken down into the following:
  1 awakening LGWR if idle
  2 LGWR gathers again to be written and issue the e/s
  3. the time for the IO journal writing complete
  4 LGWR I/O post processing
  ...
  
  Notes on adjustment according to log file sync component breakdown above:
  Steps 2 and 3 are accumulated in the statistic "redo write time". (that is found in the SEO Title Statspack and AWR)
  Step 3 is the wait event "log file parallel write. (Note.34583.1: "log file parallel write" reference Note :) )
  
  MetaLink said there is overlap as "remake the writing time" include steps 2 and and "log file parallel write" don't understand step 3, so time to "log file parallel write" is only part of the time of 'redo write time. Won't the metalink note, or I missed something?
  

• synchronization of log file much larger than log file parallel write

  Hi all

  average of log file sync wait is 30 ms log file parallel write is only 10 ms, this mean? What are the main reasons for this difference?

  Sincerely yours.

  A. U.

  Hello

  average of log file sync wait is 30 ms log file parallel write is only 10 ms, this mean? What are the main reasons for this difference?

  Essentially, when newspaper writer writes, several session may be waiting. During 10 ms of time, you can have a written lgwr and sessions of 3 user waiting on the 'log file sync '.

  Kind regards

  Franck.

• log file parallel write

  Hello
  on the 11g R2. I have the following:

  SQL> select  total_waits, time_waited from v$system_event where event='log file parallel write';
  
  TOTAL_WAITS TIME_WAITED
  ----------- -----------
        74144       28100

  Is it too or not? These valuses, which should be compared?
  
  
  Thank you.

  Hello

  You can refer to http://docs.oracle.com/cd/E11882_01/server.112/e16638/instance_tune.htm#PFGRF94563 .

  What is the current size of the redo log files?

  Anand

• long log file sync waits

  Hello
  
  I am trying to improve the performance of a 10.2.0.5 database who is suffering from the high value of the log file sync wait. AWR reports show that it is almost never less than 20% of the time of database, normally it is 20-30%, and it is consistently above not-idle wait event. Many sessions he takes 80-90% of the time or more.
  
  Log file parallel write is an order of magnitude lower, probably isn't an I/O problem. The database performs about 100 commits per second, the ratio of user-call-to-commit is about 20, again generated 500 k/s, log buffer is big 14 MB. There are about 6-7 journal file switches per hour on average.
  
  There are several oddities on log file sync wait here and I'd appreciate any help unravel them:
  
  1) there are almost two file sync wait events in the log by a posting on average (number of parallel expectations of log file is about the same number of validations). Why?
  (2) according to the ASH, nearly half of log file sync waits take near Ms. 97.7 is something special reason for this pic?
  (3) approximately 0.5% of the log file sync waits captured by ASH see the multisecond wait times. No idea where they may come from or how to diagnose this kind of problem?
  
  Some parts of an AWR report below, please let me know if anything else is needed.
  
  Best regards
  Nikolai
  

  Cache Sizes
  ~~~~~~~~~~~                       Begin        End
                               ---------- ----------
                 Buffer Cache:    44,592M    44,672M  Std Block Size:        16K
             Shared Pool Size:     3,104M     3,024M      Log Buffer:    14,288K
  
  Load Profile
  ~~~~~~~~~~~~                            Per Second       Per Transaction
                                     ---------------       ---------------
                    Redo size:            545,833.77              6,659.29
                Logical reads:            225,711.23              2,753.73
                Block changes:              1,788.11                 21.82
               Physical reads:              1,195.98                 14.59
              Physical writes:                119.02                  1.45
                   User calls:              2,368.64                 28.90
                       Parses:                737.35                  9.00
                  Hard parses:                 94.58                  1.15
                        Sorts:                261.75                  3.19
                       Logons:                  5.93                  0.07
                     Executes:              1,796.12                 21.91
                 Transactions:                 81.97
  
  Top 5 Timed Events                                         Avg %Total
  ~~~~~~~~~~~~~~~~~~                                        wait   Call
  Event                                 Waits    Time (s)   (ms)   Time Wait Class
  ------------------------------ ------------ ----------- ------ ------ ----------
  CPU time                                         23,580          19.8           
  log file sync                       491,840      21,976     45   18.5     Commit
  db file sequential read           1,902,069      12,604      7   10.6   User I/O
  read by other session               743,414       4,159      6    3.5   User I/O
  log file parallel write             220,772       3,069     14    2.6 System I/O
  
            -------------------------------------------------------------       
  
  Instance Activity Stats            ******************
  
  Statistic                                     Total     per Second     per Trans
  -------------------------------- ------------------ -------------- -------------
  Cached Commit SCN referenced                 11,130            3.1           0.0
  Commit SCN cached                                 3            0.0           0.0
  DB time                                  12,547,531        3,483.3          42.5
  DBWR checkpoint buffers written             145,437           40.4           0.5
  DBWR checkpoints                                  6            0.0           0.0
  ...
  IMU CR rollbacks                              2,566            0.7           0.0
  IMU Flushes                                  36,411           10.1           0.1
  IMU Redo allocation size                187,480,124       52,045.3         635.0
  IMU commits                                 255,350           70.9           0.9
  IMU contention                               11,998            3.3           0.0
  IMU ktichg flush                                 11            0.0           0.0
  IMU pool not allocated                        4,295            1.2           0.0
  IMU recursive-transaction flush                 175            0.1           0.0
  IMU undo allocation size              2,029,937,952      563,519.5       6,875.1
  IMU- failed to get a private str              4,295            1.2           0.0
  ...
  background checkpoints completed                  6            0.0           0.0
  background checkpoints started                    6            0.0           0.0
  background timeouts                          11,400            3.2           0.0
  ...
  change write time                             9,398            2.6           0.0
  cleanout - number of ktugct call             54,233           15.1           0.2
  cleanouts and rollbacks - consis              9,436            2.6           0.0
  cleanouts only - consistent read              2,028            0.6           0.0
  ...
  
  Instance Activity Stats            *******************
  
  Statistic                                     Total     per Second     per Trans
  -------------------------------- ------------------ -------------- -------------
  commit batch performed                           61            0.0           0.0
  commit batch requested                           61            0.0           0.0
  commit batch/immediate performed                 94            0.0           0.0
  commit batch/immediate requested                 94            0.0           0.0
  commit cleanout failures: block                  51            0.0           0.0
  commit cleanout failures: buffer                 14            0.0           0.0
  commit cleanout failures: callba              8,632            2.4           0.0
  commit cleanout failures: cannot             10,575            2.9           0.0
  commit cleanouts                            991,186          275.2           3.4
  commit cleanouts successfully co            971,914          269.8           3.3
  commit immediate performed                       33            0.0           0.0
  commit immediate requested                       33            0.0           0.0
  commit txn count during cleanout             61,737           17.1           0.2
  ...
  redo blocks written                       4,078,889        1,132.3          13.8
  redo buffer allocation retries                  177            0.1           0.0
  redo entries                              1,924,106          534.1           6.5
  redo log space requests                         174            0.1           0.0
  redo log space wait time                      2,333            0.7           0.0
  redo ordering marks                           4,553            1.3           0.0
  redo size                             1,966,229,700      545,833.8       6,659.3
  redo subscn max counts                       38,227           10.6           0.1
  redo synch time                           2,233,166          619.9           7.6
  redo synch writes                           352,935           98.0           1.2
  redo wastage                             56,259,980       15,618.0         190.5
  redo write time                             316,495           87.9           1.1
  redo writer latching time                        19            0.0           0.0
  redo writes                                 220,866           61.3           0.8
  rollback changes - undo records                 134            0.0           0.0
  rollbacks only - consistent read             11,242            3.1           0.0
  ...
  
  ...
  transaction rollbacks                            94            0.0           0.0
  transaction tables consistent re                 25            0.0           0.0
  transaction tables consistent re              8,704            2.4           0.0
  undo change vector size               1,176,156,772      326,506.2       3,983.5
  user I/O wait time                        2,039,881          566.3           6.9
  user calls                                8,532,422        2,368.6          28.9
  user commits                                295,139           81.9           1.0
  user rollbacks                                  122            0.0           0.0
  ...
            -------------------------------------------------------------       

  High "log file synchronization" waits arise also when LGWR is unable to get the CPU to republish on the boy that the log write is complete. The boy expected this event until LGWR may be a sign but if LGWR is unable to get the CPU, it is unable to signal quite quickly.

  8 processors for 1 hour is 28 800 seconds. 7 UC is an odd number. This is equivalent to 25 200 seconds available. Your AWR shows that Oracle has represented time seconds 23 580 CPU. So, your server is probably encounter situations where processes are unable to get the CPU.

  You can pin or renice LGWR - but you need to check with Oracle Support if this is doable on your platform or supported.

  What you need to do is to adjust the sessions that make very high logical reads (a simple rule is 10 k blocks per CPU per second and you hit 225 K blocks for 7 processors!) to reduce the logical reads and CPU consumption.
  OR add more CPU.

  Hemant K Collette
  http://hemantoracledba.blogspot.com

  Hemant K Collette

• log file sync wait

  Hello world

  DB 11.2.0.1 - hearts 32 - 64 GB of RAM

  I have a database of 1.5 million records are inserting all hours into it. This database is suffering too log sync wait. Googling the question I found that the reason is the way enforcement is the insertion of data in the database that has an insert preceded a commit after each of them. Currently, we are unable to change the method of insertion to use batch inserts instead. The number of files in the database redolog is 22 each of size 200 MB and the log_buffer is about 150 MB.

  is there a solution to reduce the number of log file sync waits?

  I tried to increase the size of log file to roll forward to 700 MB of each, but there was once some claim buffer waits. the SGA is 38 GB.

  Thanks for any guidance

  concerning

  You could try commit year writing setting method. In the example here,.

  One of the ways to eliminate the log_file_sync awaits

  I eliminate log file sync.

• How to cancel the installation of event on my computer files

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  assuming that I have 5 pc as my host, I want that they cannot delete all files, but can create a file or a folder and can change?

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  I am trying to use the PSR as a domain user, but get the following error message when you try to save my record:

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  If I run the present when logged in as a domain administrator, I can record without problem.  But when logged in as a domain user, I get the error.  I tried "Run as Administrator" as well as "Run as different user", enter the domain administrator credentials, but still get the error.
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  Hello Giblits,

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• Broker configuration files not be created at the level of the BONE

  DB version: 12.1.0.2 on Oracle Linux 6.7

  Type: Physical standby

  I'm trying to set up data guard broker for my own DB. Primary and standby phyical are autonomous DBs.

  As the first step, I tried to create a broker configuration files in the following locations. But it is not created is at the level of the BONE.

  No idea why?

  SQL > ALTER SYSTEM SET DG_BROKER_CONFIG_FILE1 = ' / oradata/DG_BROKER/dr1APGCMS.dat' scope = both;

  Modified system.

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  Modified system.

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  $ ls-l /oradata/DG_BROKER/dr1APGCMS.dat

  method: cannot access the /oradata/DG_BROKER/dr1APGCMS.dat: no such file or directory

  $

  $

  $ ls-l /datastore/DG_BROKER/dr2APGCMS.dat

  method: cannot access the /datastore/DG_BROKER/dr2APGCMS.dat: no such file or directory

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  Modified system.

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  Oracle 7577 1 0 22:43?        00:00:00 ora_dmon_APGCMS

  -extract from the primary alerts log

  ALTER SYSTEM SET dg_broker_config_file1='/oradata/DG_BROKER/dr1APGCMS.dat' SCOPE = BOTH;

  Sat Dec 26 22:41:49 2015

  ALTER SYSTEM SET dg_broker_config_file2='/datastore/DG_BROKER/dr2APGCMS.dat' SCOPE = BOTH;

  Sat Dec 26 22:43:39 2015

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  Sat Dec 26 22:43:39 2015

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  Sat Dec 26 22:43:39 2015

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  Sat Dec 26 22:43:42 2015

  From Data Guard Broker (MICHAEL)

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  INSV started with pid = 43, OS id = 7579

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• Unable to turn on Creative Cloud File Sync

  I can't turn on Creative Cloud File Sync. On a Mac equipped with Mavericks, I go to the creative cloud icon and click on it, then the assets. It takes me to the files tab and gives me a big blue button that says "Start Sync". If I click it, the app will blink briefly, and then I'm back to the tab of the files with the big blue button "Start Sync". If I click it again, I get an icon of spinning for about five minutes, and then I am to the app once again, with the big blue button.

  LHillVisualAdvan,

  Please check the full path that is not found, if you see "no such file or directory". I think the message in the command line to look like this:

  rm: /Users//Library/Application Support/Adobe/CoreSync/options.tix: No such file or directory
  

  If you do not see /Users/ initially,'re missing you the tilde character ("~") instructions.

  If the path is similar to that above, and options.tix is not found, the problem you are experiencing is distinct from that described in the knowledge base article. In this case, could you send us your log files so that we can investigate further? If Please zip the entire folder "CoreSync" at the following location and send it to me at [email protected].

  Mac:

  /Users//Library/Application Support/Adobe/CoreSync

  Windows:

  C:\Users\\AppData\Roaming\Adobe\CoreSync

  'Library' on Mac and "AppData" in Windows is two hidden folders. Please read this help page on these folder view:

  http://helpx.Adobe.com/x-productkb/global/show-hidden-files-folders-extensions.html

  Thank you

  Ben

• How to view the hold file that is created in sql

  Hello
  
  
  Oracle version: 10g
  
  OS version: linux 4
  
  I'm upgrading to 10.2.0.1.0 to 10.2.0.4.0
  
  in the process, I followed a document.
  In this, he said
  coil track.log
  - - -- -
  
  - -- - -- - -
  
  spool off
  
  now, I want to view the track.log file?
  It is created?
  He was born at the level of the os or it is just a logical file for this period, as long as we are connected to sql?
  
  
  pls help
  
  thnx

  its created on the operating system where you ran the command the coil.

  That is, if you run the command of the coil of the directory will, the file will be created there.

  the file is created immediately after you run the command. But what command is specified that ends in writing in this file.

  If you want to generate the file in a specific location/path, you can specify the full path when executing this command of the coil, for example,.

  coil /abc/track.log

  Here the track.log file will be created in the folder will.

  PS mark the post responded to clean up the forum. Thank you.

• ODB file is not created

  I have two portable devices that produce both the same error. one is windows mobile 5 the second is windows mobile 6.1
  
  When I download and install an application the odb file (obs, the file data of two files and) are not created. even in the demo of transport which is published on the mobile server when downloaded
  in the Pocket and properly installed, odb files are not created. I tried to create my own application, create the tables in the software library, snapshots, etc. sequences, then then I published and downloaded to the terminal. odb database was not created.
  
  Please assist.thank you for your time
  
  PSI do not know if it has to do with my error
  If I choose the Packaging Wizard to create a sql query records only in some .sql files sql statements that implement the database?
  If so how can I run from my pocket computer.
  
  
  Published by: user2955130 on Sep 17, 2009 07:41
  
  Published by: user2955130 on Sep 17, 2009 07:41
  
  Published by: user2955130 on Sep 17, 2009 07:42
  
  Published by: user2955130 on Sep 17, 2009 07:42

  for the first question, the database file does not is downloaded, because when you created a new user, that it worked, my guess would be that the user does not instantiate correctly.

  In mobile manager > data synchronization > publications > users you should see a list of users associated with the application, and there is a flay to show if the user is successfully instantiated. If it is NOT, then there is a problem with the user being added to the publication, perhaps in data binding specified which create subsets of parameters.

  The database if you
  Select * from c$ all_client_items where clientid = then you should see all Articles in the publication for publication-, if you not, yet once something does not.

  If everything seems to be ok, then turn on the trace of the synchronization on the user in mobile manager and look at the logs generated, they tend to point you to the problem

  Regarding the access violation, for MSQL for conscli data do not change the user or password, simply connect (name of user and password is actually System/Manager, which is the default). for a database application, the user names is still system, but the password is the password for user

  so, if you have a user test1, password pass1
  for conscli - Manager/system
  application - system/pass1

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• creating index Impdp and parallel

  This can be a very basic question for most of you, but...
  
  Can someone explain that under with parallel impdp = n will lead to creating treats 1 index both with n PX (suppose I have n dump files)? Or it will create index n at the same time each process n PX? Issue DDL (1 parallel) parallel impdp = n option should not be indexed?
  
  How the result is different if I have only 1 file dump? Impdp will use n processes to read the dump file 1?
  
  I want to talk about 11 GR 2 EA.

  Indexes are created in series, but built using parallel slaves.

  Let's say you have foo index that was created like this

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  Dean