Asynch write lock

Hi All,
My database has asynch write enabled and one DBWR and 4 Slaves for it. I want to know if having 4 slaves will cause a lock(enqueue waits) on any table. Say during the Loading process, all the 4 slaves are trying to update a table and slave 1 has updated a record and slave 2 also wants to update that record. So will slave 2 wait till slave 1 commits? What will happen in this case?

Locks on database tables and table rows are taken by transactions accessing data: user transactions are run by dedicated server processes or shared server processes or job queue processes but not by background processes such as DBWR or I/O slaves. User transactions update the buffer cache and on some specific events, the buffer cache is written to disk: http://download-uk.oracle.com/docs/cd/B10501_01/server.920/a96524/c09procs.htm#6162.

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Installing Mountain Lion from Snow Leopard, Install failed and HD write-locked

I recently downloaded the mountain lion installer from the App Store and I ran the installer. Stupid person as I am, I did not have any backups for my file and I naively assumed that an apple OS installer would be without flaws. Boy, was I wrong. I need every bytes of my data (or close to every bytes) but the installer failed.
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So I tried to first back up all files in Macintosh HD to an external hard drive using Disk Utilities, and I used features such as "New Image" and "Restore" but they both ended up in "Input/Output error". I tried many methods with Disk Utilities but they resulted in errors.
After some research, I noticed that some people's computers worked after they reset their PRAM. So that's what I did. I held command+option+P+R when computer started up and I reset the PRAM. When the start up disk (which is the OS installer, not the normal operating system) loaded, I was greeted with choose languages option and then I was back in the Mountain Lion installer state. I again ran the installer again, hoping something would be different, but then it was different. But not in a good way. When I was told to choose where I would like to install Mountain Lion, I noticed that Macintosh HD was grayed out. Last time, I was at least able to run the installer but this time, Macintosh HD was grayed out. The installer said that my Macintosh HD was locked. After some research, I learned that apparently, the Mountain Lion installer write-locks Macintosh HD mid installation.
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a. so how can I un-write-lock Macintosh HD?
2. More realistically, I am thinking of borrowing someone else's macintosh computer and use it as the backup center. I have a firewire cable and a terrabyte external hard drive. So what I'm thinking is that I'll hook my computer in target mode to my friend's computer and I will also plug in my external hard drive to my friend's computer and then I can download and run Carbon Copy Cloner from my friend's computer to copy all data from my Macintosh HD to my external hard drive. And then I will erase my Macintosh HD, freshly install Mountain Lion onto it and then copy all data back from my external hard drive. But I am not sure about few things.
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b. will my computer allow me to erase (or format) Macintosh HD?
c. will my erased/formatted Macintosh HD able to install + be installed Mountain Lion OS?
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I'm not sure where you read that about the disk being "write-locked." That doesn't make much sense, given that the major task an installer like this must achieve is writing a whole bunch of files to the hard drive. I think your source was mistaken.
As to what happened, it sounds like your hard drive was badly corrupt to start with, or possibly was on the edge of failing and is now in the process of dying entirely. If you don't have backups of your data, that does not bode well for you, unfortunately. If you can manage to use target mode to copy your data, do that.
Once you're sure you've got all your data, you need to start up from your Snow Leopard install disk and repair the hard drive. (Since it sounds like the Mountain Lion installer didn't work, I wouldn't trust the recovery partition that Mountain Lion installs.) Or, even better, just erase the hard drive entirely and reinstall Snow Leopard. Then, once you're back up and running, with all your data back on the system and with Snow Leopard updated to the most recent version, try installing Mountain Lion again. If any of that fails again, the problem is likely to be a dying hard drive, and you'll need to replace it.

Error : MDSConfig failed to acquire write lock??

Hi,
Changes that I know used to flow, don't flow anymore, and I was suspecting something was wrong with the changelog followup.
I guess I was right, cause I see this in the meta-.xxx.log:
MDSConfig failed to acquire write lock 'MDS_E_FAILED_TO_ACQUIRE_WRITE_LOCK' (80042212), wlock=(fe3f1c40), rlock
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MDS = 5.0SP1
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i sometimes see such messages on startup
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Hello,
One of my transactions changes many records in the database and often I need 30 and
more tries, until the transaction is done without deadlocks.
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expensive transaction has finished?
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Hi Josef,
I would suggest starting by reviewing the information in chapters 9 and 14 in the Reference Guide ("Berkeley DB Transactional Data Store Applications", "The Locking Subsystem"):
http://www.oracle.com/technology/documentation/berkeley-db/db/ref/toc.html
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http://www.oracle.com/technology/documentation/berkeley-db/db/ref/transapp/read.html
http://www.oracle.com/technology/documentation/berkeley-db/db/ref/transapp/deadlock.html
http://www.oracle.com/technology/documentation/berkeley-db/db/ref/transapp/tune.html
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Regards,
Andrei

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Thanks!

Hi,
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Best regards,
Robert

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Hi
We have sheduled a job to run the DWH workflows nightly . We are on version 11.2.0.2.0
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grateful for some help on this issue.
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Please delete this post and repost in the appropriate forum. Thank you.

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It doesn't sound like you have a good background in concurrency yet. Take a look at this book.
http://java.sun.com/docs/books/cp/
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What mechanism would you suggest to implement Reader-Writer locks across unrelated processes?
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Synchronization Across Process Boundaries
Each of the synchronization primitives can be set up to be used across process
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located in a shared memory segment and by calling the appropriate init() routine,
after the primitive has been initialized with its shared attribute set as interprocess.
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What mechanism would you suggest to implement Reader-Writer locks across unrelated processes?
Though the documentation for pthread_rwlock_ functions state
Synchronization Across Process Boundaries
Each of the synchronization primitives can be set up to be used across process
boundaries. This is done quite simply by ensuring that the synchronization variable is
located in a shared memory segment and by calling the appropriate init() routine,
after the primitive has been initialized with its shared attribute set as interprocess.
but they work only if the processes are forked off from a given process which initialized the relevant synchronization variable and not if the processes are totally unrelated.

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Hi,
IIn MDM7.1 new feature is added where we will get this feature ie during concurrent read and wrire actions(write lock optimization),how it will work.
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Hi Pallavee,
Thanks for clarifying.
In MDM 5.5 , 'Write' process was a performance bottleneck . In 5.5, Write process locks the record and blocks the user to Read the records while performing update. If a batch run of updates is performed then user access was interrupted until the records were updated.
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Vinay M.S

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Hi All,
Does anyone know what does this error mean?
com.sap.b1i.xcellerator.XcelleratorException:
XCE001 Nested exception: com.sap.b1i.xcellerator.RejectedException:
XCE061 Could not obtain a maintenance-read + write-Lock for DBQueue/QStream/jobID Q.INB_IQ_INTQ_ASYN_QS.0010000000
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SQLPLUS @ command should open script file with a WRITE lock

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If you ever find this answer, it would be extremely useful to me right now.

Device is write locked

How to reset password.
I have tried these steps but no luck
/sbin/fsck -fy
/sbin/mount -uw /
passwd root
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reboot
Anybody can help

First, make sure caps lock is not on.
You must back up all data before continuing, unless you've already done so. If you need to back up but can't log in, ask for instructions.
If the user account is associated with an Apple ID, and you know the Apple ID password, then maybe the Apple ID can be used to reset your user account password.
Otherwise*, boot into Recovery mode. When the OS X Utilities screen appears, select
Utilities ▹ Terminal
from the menu bar. In the Terminal window, type this:
res
Press the tab key. The partial command you typed will automatically be completed to this:
resetpassword
Press return. A Reset Password window opens.
Select your boot volume ("Macintosh HD," unless you gave it a different name) if not already selected.
Select your username from the menu labeled Select the user account if not already selected.
Follow the prompts to reset the password. It's safest to choose a password that includes only the characters a-z, A-Z, and 0-9.
Select
 ▹ Restart
from the menu bar.
You should now be able to log in with the new password, but your Keychain will be reset (empty.) If you've forgotten the Keychain password (which is ordinarily the same as your login password), there's no way to recover it.
*Note: If you've activated FileVault, this procedure doesn't apply. Follow instead the instructions on this page:
If you forget the password and FileVault is on

Another client has the SDB write lock

I would like to be able to change some of the settings on my Arris NVG510 but I get this message. Can anyone help with it. I've done a lot of searching and can't find any discussion about it.

kevinhilkey wrote:
I would like to be able to change some of the settings on my Arris NVG510 but I get this message. Can anyone help with it. I've done a lot of searching and can't find any discussion about it.
Sounds like it's a refurbed unit that they changed the password, but forgot to change the sticker on the outside.
Click the ATT Uverse Care link in my signature, send the PM, explain your situation.
Include your account #, email address and a good phone # (land or cell) and time to contact you on.
Check the blue PM envelope, upper right on every page, for their reply.
Possibly they can get it from going in on their end. Good luck
Chris
Please NO SD stretch-o-vision or 480 SD HD Channels
Need Help? PM ATT Uverse Care (all service problems)
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Asynch write lock

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