About lock

Delete data from table. The command is following:
Delete from utela.ta9cb01;
Error:
6003: Lock request denied because of time-out.
Details: Tran 4.689(pid 9949) wants Un lock on rowid BMUFVUAAAAAAboMBGw,
table UTELA.TA9CB01.
But Tran 2041.27283048(pid 107) has it in Xn(request was Xn). Holder SQL().
The command failed.
How do I force this situation to unlock? What command can I use?
Thanks.

You have two different transactions trying to modify the same row(s) in this table. When the transaction holding the locks is comitted (or rolled back) then the other ione will be able to proceed. You have the process ids of the processes holding the locks in the error messages. You can use ttStatus to get more detail as to which processes these are. They are most likely application processes.
Chris

Similar Messages

ı have installed an application about lock system but the application isnt about lock systm this is an code reader. when ı see the application's pictures this is an lock application but content not same. I have got laid...what shoul I do?

I have installed an application about lock system but the application isnt about lock system this is an code reader. When ı see the application's pictures this is an lock application but content not same. I have got laid...what should I do?

semihtinas wrote:
Please make something these fraudsters
You're not addressing Apple here. This is a user to user technical support forum. You can submit feedback to Apple here:
http://www.apple.com/feedback
Other contact information can be found using the Contact Us link at the bottom right of every page.

Idea Please about lock...

How do set lock and unlock to the file and pls give me any sample and basic idea about lock...

What? I don't understand your question :(
Btw. Is this for a test, or homework?
/Kaj

Need details about "Lock Profiling" tab of JRockit JRA

Hi,
I'm experimenting with the JRockit JRA tool: I think this is a very useful tool ! It provides very valuable information.
About locks ("Lock Profiling" tab), since JRockit manages locks in a very sophisticated manneer, it enables to get very important information about which monitors are used by the application, helping for improving the performances.
Nevertheless, the BEA categories (thin/fat, uncontended/contended, recursive, after sleep) are not so clear. A short paper explaining what they mean would greatly help.
Fat contended monitors cost the most, but maybe 10000 thin uncontended locks cost the same as 1 fat contended lock does. We don't know.
So, there is a lack of information about the cost (absolute: in ms, or relative: 1 fat lock costs as N thin locks) of each kind of monitor. This information would dramaticaly help people searching where improvements of lock management are required in their application.
Thanks,
Tony

great explanation! Thanks
"ihse" <[email protected]> wrote in message
news:18555807.1105611467160.JavaMail.root@jserv5...
About thin, fat, recursive and contended locks in JRockit:
Let's start with the easiest part: recursive locks. A recursive lock
occurs in the following scenario:synchronized(foo) { // first time thread takes lock
synchronized(foo) { // this time, the lock is taken recursively
}The recursive lock taking may also occur in a method call several levels
down - it doesn't matter. Recursive locks are not neccessarily any sign of
bad programming, at least not if the recursive lock taking is done by a
separate method.
The good news is that recursive lock taking in JRockit is extremely fast.
In fact, the cost to take a lock recursively is almost negligable. This is
regardless if the lock was originally taken as a thin or a fat lock
(explained in detail below).
Now let's talk a bit about contention. Contention occurs whenever a thread
tries to take a lock, and that lock is not available (that is, it is held
by another thread). Let me be clear: contention ALWAYS costs in terms of
performance. The exact cost depends on many factors. I'll get to some more
details on the costs later on.
So if performance is an issue, you should strive to avoid contention.
Unfortunately, in many cases it is not possible to avoid contention -- if
you're application requires several threads to access a single, shared
resource at the same time, contention is unavoidable. Some designs are
better than others, though. Be careful that you don't overuse
synchronized-blocks. Minimize the code that has to be run while holding a
highly-contended lock. Don't use a single lock to protect unrelated
resources, if that lock proves to be easily contended.
In principle, that is all you can do as an application developer: design
your program to avoid contention, if possible. There are some experimental
flags to change some of the JRockit locking behaviour, but I strongly
discourage anyone from using these. The default values is carefully
trimmed, and changing this is likely to result in worse, rather than
better, performance.
Still, I understand if you're curious to what JRockit is doing with your
application. I'll give some more details about the locking strategies in
JRockit.
All objects in Java are potential locks (monitors). This potential is
realized as an actual lock as soon as any thread enters a synchronized
block on that object. When a lock is "born" in this way, it is a kind of
lock that is known as a "thin lock". A thin lock has the following
characteristics:
* It requires no extra memory -- all information about the lock is stored
in the object itself.
* It is fast to take.
* Other threads that try to take the lock cannot register themselves as
contending.
The most costly part of taking a thin lock is a CAS (compare-and-swap)
operation. It's an atomic instruction, which means as far as CPU
instructions goes, it is dead slow. Compared to other parts of locking
(contention in general, and taking fat locks in specific), it is still
very fast.
For locks that are mostly uncontended, thin locks are great. There is
little overhead compared to no locking, which is good since a lot of Java
code (especially in the class library) use lot of synchronization.
However, as soon as a lock becomes contended, the situation is not longer
as obvious as to what is most efficient. If a lock is held for just a very
short moment of time, and JRockit is running on a multi-CPU (SMP) machine,
the best strategy is to "spin-lock". This means, that the thread that
wants the lock continuously checks if the lock is still taken, "spinning"
in a tight loop. This of course means some performance loss: no actual
user code is running, and the CPU is "wasting" time that could have been
spent on other threads. Still, if the lock is released by the other
threads after just a few cycles in the spin loop, this method is
preferable. This is what's meant by a "contended thin lock".
If the lock is not going to be released very fast, using this method on
contention would lead to bad performance. In that case, the lock is
"inflated" to a "fat lock". A fat lock has the following characteristics:
* It requeries a little extra memory, in terms of a separate list of
threads wanting to acquire the lock.
* It is relatively slow to take.
* One (or more) threads can register as queueing for (blocking on) that
lock.
A thread that encounters contention on a fat lock register itself as
blocking on that lock, and goes to sleep. This means giving up the rest of
its time quantum given to it by the OS. While this means that the CPU will
be used for running real user code on another thread, the extra context
switch is still expensive, compared to spin locking. When a thread does
this, we have a "contended fat lock".
When the last contending thread releases a fat lock, the lock normally
remains fat. Taking a fat lock, even without contention, is more expensive
than taking a fat lock (but less expensive than converting a thin lock to
a fat lock). If JRockit believes that the lock would benefit from being
thin (basically, if the contention was pure "bad luck" and the lock
normally is uncontended), it might "deflate" it to a thin lock again.
A special note regarding locks: if wait/notify/notifyAll is called on a
lock, it will automatically inflate to a fat lock. A good advice (not only
for this reason) is therefore not to mix "actual" locking with this kind
of notification on a single object.
JRockit uses a complex set of heuristics to determine amongst other
things:
* When to spin-lock on a thin lock (and how long), and when to inflate it
to a fat lock on contention.
* If and when to deflate a fat lock back to a thin lock.
* If and when to skip on the fairness on a contended fat lock to improve
performance.
These heuristics are dynamically adaptive, which means that they will
automatically change to what's best suited for the actual application that
is being run.
Since the switch beteen thin and fat locks are done automatically by
JRockit to the kind of lock that maximizes performance of the application,
the relative difference in performance between thin and fat locks
shouldn't really be of any concern to the user. It is impossible to give a
general answer to this question anyhow, since it differs from system to
system, depending on how many CPU:s you have, what kind of CPU:s, the
performance on other parts of the system (memory, cache, etc) and similar
factors. In addition to this, it is also very hard to give a good answer
to the question even for a specific system. Especially tricky is it to
determine with any accuracy the time spent spinning on contended thin
locks, since JRockit loops just a few machine instuctions a few times
before giving up, and profiling of this is likely to heavily influence the
time, giving a skewed image of the performance.
To summarize:
If you're concerned about performance, and can change your program to
avoid contention on a lock - then do so. If you can't avoid contention,
try to keep the code needed to run contended to a minimum. JRockit will
then do whatever is in its power to run your progam as fast as possible.
Use the lock information provided by JRA as a hint: fat locks are likely
to have been contended much or for a long time. Put your effort on
minimizing contention on them.

About lock object

I have one TABLE with TABLE MAINTENANCE GENERATOR
and it has also LOCK OBJECT.
Now I have adjusted the table by making some normal fields as primary keys
and regenerated Table maintenance generator ,
It seems to me lock object also adjusted( I am able to see the newly converted primary key fields in lock object( in se11 ) ).
Does the lock object automatically adjusts ????
If lock object adjusts automatically --> what about the function modules ENQUEUE_ztable DEQUEUE_ztable ? these function modules also gets adjusted ?
do I need to check the associated lock object impact ?
How can I check ?

Hi,
No need to delete the Lock object. Just remove the Table which you modified from Lock object & add again. You can add the lock Parameters manually. It will be drived automatically from Table key fields.
You no need to delete the lock object.
Raja T
Message was edited by:
Raja T

A string of question about Locking & Isolation Level

Hi All
It is highly appreciated if someone give offer answers to my below questions
1) There are two ways of locking mechanism: Pessimistic & Optimistic. In general, do all J2EE app server support all these two ways of locking ?
2) It seems to me that setting the isolation level to "serialization" should result in using pessmistic locking. If no so, please point out my misconcept and explain to me.
3) Are there any differences in the way of entity bean programming as different locking mechansim is adopted ?
4) With regard to optimistic locking, will the app server throw out exception as data contention is detected ? Is the way of handling dependent on app server? Or It is transparent to the developer of entity bean. Please give me an e.g of j2ee app server product how to handle this scenario.
5) To adopt the approach of "optimistic" locking, do l have to implement it on my own using bean managed entity bean.
6) It seems to me that optimistic locking can achieve better concurrency. If it is inherently supported by app server for its container managed entity bean (=> totally transparent to the developer of entity bean). Is it always the rule of thumb to config the server to use "optimistic" locking instead of "pessimistic" ?
Sorry for bombarding you guys with such long list of questions. l would be very thankful if someone can help me consolidate my concept on these topics.
Also, please send your reply to [email protected] as well
thanks & regards
Danny

Hi Danny,
I became interested about the optimistic locking recently. If the topic is not long forgotten then this may make some difference!
We have attacked the optimistic locking issue by introducing audit fields (MODIFY_BY_USER, MODIFY_DATE) in tables where concurrency needs to be implemented.
We are retrieving rows from the table (for display or update) through Stateless Session Bean using simple SQL SELECT. The audit fields are fetched along with the business data and are kept at the client. While any of the concurrent users tries to update the row the audit fields are sent to the application server along with the modified business data. The relevant Entity Bean checks for any difference in the timestamp of the audit field (MODIFY_DATE) value with the value in the database. If a mismatch is found it reports a business exception to the user. Otherwise, the row is updated with the lastest timestamp value in the audit field MODIFY_DATE.
This works fine when two update operations are not concurrent, i.e., two users submit their update requests in a time lag greater than the time taken by the transaction to complete. This alone could not prevent the dirty update on the database.
Hence, to prevent any concurrent update contending for the same row you need to set the following ejbgen tag in the Entity Bean:
concurrency-strategy = Exclusive<<<<<Note: We are using Weblogic 6.1 with SP4 and CMP (no BMP).
Please let me know if you have got a better solution to tackle this issue.
Chandra.

About lock object and how to create it

Hi ABAP gurus,
Can any one explain about the Lock Objects and How to create Lock object step by step.
Rgds,

Hi Rangamma,
Check this info.
Lock objects are use in SAP to avoid the inconsistancy at the time of data is being insert/change into database.
SAP Provide three type of Lock objects.
- Read Lock(Shared Locked)
protects read access to an object. The read lock allows other transactions read access but not write access to
the locked area of the table
- Write Lock(exclusive lock)
protects write access to an object. The write lock allows other transactions neither read nor write access to
the locked area of the table.
- Enhanced write lock (exclusive lock without cumulating)
works like a write lock except that the enhanced write lock also protects from further accesses from the
same transaction.
You can create a lock on a object of SAP thorugh transaction SE11 and enter any meaningful name start with EZ Example EZTEST_LOCK.
Use: you can see in almost all transaction when you are open an object in Change mode SAP could not allow to any other user to open the same object in change mode.
Example: in HR when we are enter a personal number in master data maintainance screen SAP can't allow to any other user to use same personal number for changes.
Technicaly:
When you create a lock object System automatically creat two function module.
1. ENQUEUE_<Lockobject name>. to insert the object in a queue.
2. DEQUEUE_<Lockobject name>. To remove the object is being queued through above FM.
Lock objects are use in SAP to avoid the inconsistancy at the time of data is being insert/change into database.
SAP Provide three type of Lock objects.
- Read Lock(Shared Locked)
protects read access to an object. The read lock allows other transactions read access but not write access to
the locked area of the table
- Write Lock(exclusive lock)
protects write access to an object. The write lock allows other transactions neither read nor write access to
the locked area of the table.
- Enhanced write lock (exclusive lock without cumulating)
works like a write lock except that the enhanced write lock also protects from further accesses from the
same transaction.
You can create a lock on a object of SAP thorugh transaction SE11 and enter any meaningful name start with EZ Example EZTEST_LOCK.
Use: you can see in almost all transaction when you are open an object in Change mode SAP could not allow to any other user to open the same object in change mode.
Example: in HR when we are enter a personal number in master data maintainance screen SAP can't allow to any other user to use same personal number for changes.
Technically:
When you create a lock object System automatically creat two function module.
1. ENQUEUE_<Lockobject name>. to insert the object in a queue.
2. DEQUEUE_<Lockobject name>. To remove the object is being queued through above FM.
http://help.sap.com/saphelp_nw04/helpdata/en/cf/21eea5446011d189700000e8322d00/content.htm
GO TO SE11
Select the radio button "Lock object"..
Give the name starts with EZ or EY..
Example: EYTEST
Press Create button..
Give the short description..
Example: Lock object for table ZTABLE..
In the tables tab..Give the table name..
Example: ZTABLE
Save and generate..
Your lock object is now created..You can see the LOCK MODULES..
In the menu ..GOTO -> LOCK MODULES..There you can see the ENQUEUE and DEQUEUE function
Lock objects:
http://www.sap-img.com/abap/type-and-uses-of-lock-objects-in-sap.htm
http://help.sap.com/saphelp_nw04s/helpdata/en/cf/21eea5446011d189700000e8322d00/content.htm
Match Code Objects:
http://help.sap.com/saphelp_nw2004s/helpdata/en/41/f6b237fec48c67e10000009b38f8cf/content.htm
http://searchsap.techtarget.com/tip/0,289483,sid21_gci553386,00.html
See this link:
http://www.sap-img.com/abap/type-and-uses-of-lock-objects-in-sap.htm
Hope this resolves your query.
Reward all the helpful answers.
Regards

Question about locking certain folders w/diff.accounts?

I'm about to let my girlfriend use my Mac, so I made a seperate account for her. I just don't want her going through all of my files and " stuff ". Is there anyway to lock certain folders in my account? I tried using parental controls but didn't find the file I wanted to Lock in the options.

Hi Aaron
When your girlfriend is logged in on her account your folders are locked to her. Your Home folders are only accessible from your account.
Matthew Whiting

HELP! Question about "Locking" ipod

I am an elementary teacher that is trying to get ipods integrated into the school curriculum, school administrators have expressed concerns about students putting inappropriate content onto the ipods, is it possible to "lock" unauthorized editing on an ipod, possibly password protection, or only allowing it to be updated on one cpu?

No, it's not possible to do what you want.
There is a screen lock that locks the iPod so another user can't use it without a code being entered, but this would lock the whole iPod.
There's no way to selectively lock specific content, either adding it or viewing it.

Question about lock switch for smart phones

i would like to ask about the lock switch for smart phones like Nokia 5800 Xpressmusic or Nokia 5230.
Will the lock switch loosen if we always slide to unlock it?

i used my 5800 for 11 months and it didn't happen at all
-you can show appreciation to my posts if it helped or useful by pressing the green Kudo star beside my post that hepled
-if my answer was the solution , so click accept as solution button
Started From Nokia 3310 , Now with Nokia N97 v.22.0.110 + N900 PR1.2

? about "Lock Audio Clip at Playhead"

I've always thought that the purpose of this feature is to make sure that audio and video clips that need to stay synced together in fact do.
Well, I just added a short video clip to my timeline--in the middle of the movie--and it moved all the video clips to the right a bit, as it should--but not the audio clips, which were locked to their respective video!
How could this happen?

Hi folks.
Since we last posted, I have discovered something new about the misbehaving audio lock. Happily, I learned that it does work for me - most of the time. I can select the audio, choose "Lock..." and if I get a yellow pushpin on both the video and audio tracks, then they are properly locked together.
Here's the catch. Sometimes I select the audio, choose "Lock..." and the yellow pushpin only appears on the video track. In that case, they are not locked, and adding video before that pin will lose the sync with the improperly locked audio track. Also, I haven't found a way to get that single pushpin to go away. I can place the playhead there and choose "Lock..." again, but that has no effect (no toggle off and on). I can select a new place in the same audio clip and choose "Lock..." but the pin doesn't move. The only workaround I have found is to move a bit past the defective pin, do a "Split video at playhead" to create a new video track, and then select a spot in the audio clip to lock with the new video clip. The new clip will get the correct double pushpins, and the audio is really locked.
Here is a screen shot of this behavior. Notice that I have several locked audio clips, and I have not placed the locks on the first frame of the video clips. You can see a defective single pushpin on the video associated with audio clip #23. I couldn't remove that pin, so I split the video clip and was able to lock down audio clip #24. (Note: the gaps in the video are intentional - when I had to change tapes. I'll fill them in with some photos, so I have to make sure that I won't lose sync.)
What do you think about that?
Regards.

Question about locking order during merge statement

Dear all.
I have a merge query with a decedent hint to prevent deadlock with another queries.
Another queries use select ~for update with same hint.
My question is that the locking order will follow the hint in this query?
Or I might use the select ~ for update before this merege.
Please give any advice about select ~for update and locking order in the query.
Thanks.
MERGE INTO A
USING
 (SELECT /*+ index_desc(C index_key) */ *
 FROM
 C
 WHERE key > :start and key < :end
 ) B
 ON ( A.KEY = B.KEY )
WHEN MATCHED THEN
 UPDATE
 SET A.v1 = B.v1

What you are doing is not going to prevent a deadlock in your, as yet, unknown version of Oracle. Reading an index does not cause deadlocks. Trying to alter an uncommitted row does.
I would suggest you code this correctly by doing a SELECT FOR UPDATE WAIT <seconds> in all transactions.
http://www.morganslibrary.org/reference/deadlocks.html#dlfu

About locks

Hello,
I asked a question about how to get the kernel PID of a thread from a
RTSJ application. David Holmes mentioned that I would needed to introduce native
code:
About the TID
Now, I was wondering if there is a similar mechanism for mutexes. Is there
a kind of "kernel ID mutex" that I can obtain directly in a Java app or
by means of native code? For example, it could be useful to get control
of the real time java application locks (shared resources, i.e. methods
or synchronized methods) from another application.
Regards,
Laura

1. Need to know more about table nature. What is the use / purpose?
2. Is any records get inserted with increasing sequential number like purchase order number / invoice nuber as a index key.
3. Or is it used as a control table to generate any sequence number of the transaction?
4. Is any explicit locking machanism implemented in the code?
5. What is the INITRAN & PCTFREE settings for this particular table?
RTGPERF,
http://groups.google.com/group/database-tuning

Two basic questions about locks in Oracle.

Hello,
This is about 9i and onwards.
I need to develop a comprehensive analysis of locks and waits and while doing so, following questions popped up.
1) What is the difference between locks and waits?
2) There is a DBA view called DBA_BLOCKERS. The standard Oracle documentation has only one line comment about this view i.e. "DBA_BLOCKER – Shows non-waiting sessions holding locks being waited-on by other sessions.
My question is : Why would a non waiting session hold locks after all? I guess that automatically repeats the question #1 from above, What is the difference between "being waited on" v/s "holding locks with wait" and "holding locks without waits"?
Thanks,
R

1) What is the difference between locks and waits? Lock - something you queue up to get and simply wait until it is available
Waits - Waiting for a Specific event to happen before it can proceed.
Re: Difference between a latch and a lock
2) There is a DBA view called DBA_BLOCKERS. The standard Oracle documentation has only one line comment about this view i.e. "DBA_BLOCKER – Shows non->waiting sessions holding locks being waited-on by other sessions.DBA_BLOCKERS displays a session if it is not waiting for a locked object but is holding a lock on an object for which another session is waiting.
HTH
-Anantha

About Locking

Hi,
How can i identify which session is blocking to other session if i find that culprirt session then can i kill that blocking session without any doubts?
How can i change lock mode example Execlusive to share mode vice versa
Regards,
Quadri

Hi,
When a dead lock happens you have an ORA-00060 error on the Alert.log which point to a trace file:
--yes but this is sometime not always while issue occur.Find below details of alert log file and trace file and let me know if you have idea anything about it to sort out.
In alert log file:
ORA-00060: Deadlock detected. More info in file /vol01/app/oracle/admin/udump/rm
s_ora_5185624.trc.
Sun Jan 24 10:43:41 2010
ORA-00060: Deadlock detected. More info in file /vol01/app/oracle/admin/udump/rm
s_ora_5185624.trc.
Sun Jan 24 10:43:44 2010
ORA-00060: Deadlock detected. More info in file /vol01/app/oracle/admin/udump/rm
s_ora_5185624.trc.
In Trace file:
DEADLOCK DETECTED ( ORA-00060 )
[Transaction Deadlock]
The following deadlock is not an ORACLE error. It is a
deadlock due to user error in the design of an application
or from issuing incorrect ad-hoc SQL. The following
information may aid in determining the deadlock:
Deadlock graph:
---------Blocker(s)-------- ---------Waiter(s)---------
Resource Name process session holds waits process session holds waits
TX-006d0023-00009d7b 38 2278 X 38 2278 X
session 2278: DID 0001-0026-000074F1 session 2278: DID 0001-0026-000074F1
Rows waited on:
Session 2278: obj - rowid = 00026761 - AAAmdhAAkAAGfbJAAX
(dictionary objn - 157537, file - 36, block - 1701577, slot - 23)
Information on the OTHER waiting sessions:
End of information on OTHER waiting sessions.
Current SQL statement for this session:
UPDATE AH_INFC_SHIPMENT_DETAIL SET STATUS = :B3 WHERE SHIPMENT_KEY = :B2 AND BAR
CODE = :B1 AND STATUS = 'CREATED'
===================================================
PROCESS STATE
It's possible to enable or disable lock on Tables with the enable / disable table lock statement. You'll find
there some application of this feature:
http://www.dba-oracle.com/real_application_clusters_rac_grid/table_locks.htm
--I am not able to open it
Many Thanks Jean-Valentin
Regards,
Quadri

About lock object in Dynpro ABAP

Hi Expert,
We develop the Dynpro ABAP program to modify SAP document on EP,
( like Sales Order, Purchase order...ect. ).
In tranditional ABAP program, we use lock object(lock entry) to lock sigle document( SO, PO.. etc. )
In Dynpro ABAP , how to lock the single document ?

You can also use the "ENQUEUE" and "DEQUEUE" function modules to lock records in WDA as well.
Check out the thread [The effect of Session Expiration on Lock Table |The effect of Session Expiration on Lock Table].
Hope it helps.

About lock

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