Enqueue Server Lock Table

Hi,
Is there a way to manually release through Visual Admin for instance a locked resource on the Enqueue Server Lock Table?
Thanks in advance.

No.
Later versions have such, but not in VA.
Regards,
Benny

Similar Messages

Enqueue Replication Server - Lock Table Size

Note : I think I had posted it wrongly under ABAP Development, hence request moderator to kindly delete this post. Thanks
Dear Experts,
If Enqueue Replication server is configured, can you tell me how to check the Lock Table size value, which we set using profile parameter enque/table_size.
If enque server is configured in the same host as CI, it can be checked using
ST02 --> Detail Analysis Menu --> Storage --> Shared Memory Detail --> Enque Table
As it is a Standalone Enqueue Server, I don't know where to check this value.
Thanking you in anticipation.
Best Regards
L Raghunahth

Hi
Raghunath
Check the following links
http://help.sap.com/saphelp_nw2004s/helpdata/en/37/a2e3ab344411d3acb00000e83539c3/content.htm
http://help.sap.com/saphelp_nw04s/helpdata/en/44/5efc11f3893672e10000000a114a6b/content.htm
Regards
Bhaskar

Query Locks Table in SQL Server 2000!!

Hi all!
I am facing a strange problem. I am using MS SQL Server 2000.
I have a JDBC program.It executes a query on a table (STUDENT) and fetches some record from it.
The query gets executed fine for the first time but when the SELECT query is executed on the same table (i.e. STUDENT) from some other block of code within the same program the program hangs at the location where resultset is pointed to the first record i.e. RS.next();
When I try to execute the SELECT query on the same table (i.e. STUDENT) from a query tool when the program is running it also gets hanged!!!
It seems that after running the query for the first time on the STUDENT table from the next time its getting hanged....i believe the Table gets locked for some reason!!
Is that normal with SQL Server 2000.....The same code works fine with other database!
Please suggest...wht has to b done to gt it fixed!
Thankz a loadz bforehand!
Arun

By default (transaction isolation level TRANSACTION_READ_COMMITTED ), SQL Server applies a shared read lock when you do a SELECT. This is should not prevent other selects on the same row / page but it will prevent updates / deletes.
I found a link that explains SQL Server locking: http://databasejournal.com/features/mssql/article.php/3289661

MM42 change material, split valuation at batch level, M301, locking table

Dear All,
I'm working on ECC 6.0 retail and I have activated split valuation at batch level. Now in MBEW for this specific material I have almost 14.400 entries.
If I try to change some material data (MM42) I receive an error message M3021 A system error has occurred while locking and then Lock table overflow.
I used SM12 to see the table (while MM42 is still running) and it seems that MBEW is the problem.
What should I do? For any material modification the system has to modify every entry in MBEW? Is there any possibility to skip this?
Thank you.

Hi,
Symptom
Key word: Enqueue
FM: A system error has occurred in the block handler
Message in the syslog: lock table overflowed
Other terms
M3021 MM02 F5 288 F5288 FBRA
Reason and Prerequisites
The lock table has overflowed.
Cause 1: Dimensions of the lock table are too small
Cause 2: The update lags far behind or has shut down completely, so that the lock entries of the update requests that are not yet updated cause the lock table to overflow.
Cause 3: Poor design of the application programs. A lock is issued for each object in an application program, for example a collective run with many objects.
Solution
Determine the cause:
SM12 -> Goto -> Diagnosis (old)
SM12 -> Extras -> Diagnosis (new)
checks the effectiveness of the lock management
SM12 -> Goto -> Diagnosis in update (old)
SM12 -> Extras -> Diagnosis in update (new)
checks the effectiveness of the lock management in conjunction with updates
SM12 -> OkCode TEST -> Error handling -> Statistics (old, only in the enqueue server)
SM12 -> Extras -> Statistics (new)
shows the statistics of the lock management, including the previous maximum fill levels (peak usage) of the partial tables in the lock table
If the owner table overflows, cause 2 generally applies.
In the alert monitor (RZ20), an overrunning of the (customizable) high-water marks is detected and displayed as an alert reason.
The size of the lock table can be set with the profile parameter u201Cenque/table_size =u201C. specifies the size of the lock table in kilobytes. The setting must be made in the profile of the enqueue server ( u2026_DVEBM.. ). The change only takes effect after the restart of the enqueue server.
The default size is 500 KB in the Rel 3.1x implementation of the enqueue table. The resulting sizes for the individual tables are:
Owner table: approx 560.
Name table: approx 560.
Entry table: approx 2240.
As of Rel 4.xx the new implementation of the lock table takes effect.
It can also be activated as described in note 75144 for the 3.1I kernel. The default size is 2000 KB. The resulting sizes for the individual tables are:
Owner table: approx 5400
Name table: approx 5400
Entry table: approx 5400
Example: with the
u201Cenque/table_size =32000u2033 profile parameter, the size of the enqueue table is set to 32000 KB. The tables can then have approx 40,000 entries.
Note that the above sizes and numbers depend on various factors such as the kernel release, patch number, platform, address length (32/64-bit), and character width (Ascii/Unicode). Use the statistics display in SM12 to check the actual capacity of the lock table.
If cause 2 applies, an enlargement of the lock table only delays the overflow of the lock table, but it cannot generally be avoided.
In this case you need to eliminate the update shutdown or accelerate the throughput of the update program using more update processes. Using CCMS (operation modes, see training BC120) the category of work processes can be switched at runtime, for example an interactive work process can be converted temporarily into an update process, to temporarily increase the throughput of the update.
For cause 3, you should consider a tuning of the task function. Instead of issuing a large number of individual locks, it may be better to use generic locks (wildcard) to block a complete subarea. This will also allow you to considerably improve the performance.

Lock table

My archival jobs continuously fails because of Lock table overflow even after increasing parameter enque/table_size and then bounced.
But in SM12 No lock entries found
Under SM12 EXTRAS -> STATISTICS OR DIAGONOSTIICS are inactive
Job logs as below...
Job started
Step 001 started (program ZRJJARC20, variant CLL4, user ID MINIO)
Archiving session 000078 is being created
Lock table overflow
Job cancelled after system exception ERROR_MESSAGE
Regards,
Peter

But i want to know why job fails even after clear lock entries in SM12.
Below find statics of locks
Enqueue Operations     42726
rejected     47
Error occured     1
Dequeue Operations     4349
Error occured     0
Dequeue All Operations     3735
Cleanup Operations     0
Backup Operations     2
Read Operations     5
Compress Operations     0
Verify Operations     0
Records written     29182
to the backup file     4
Maximum Number of Lock Owners     25311
Maximum Fill level     8
Current Fill Level     6
Maximum Number of Lock Arguments     25311
Maximum Fill level     25310
Current Fill Level     6
Maximum Number of Lock Entries     25311
Maximum Fill level     25310
Current Fill Level     6
Update; Fill Level at Maximum     1
Current Fill Level     0
Time in Lock Table /Seconds     2.876618s
Wait for Lock Table /Seconds     0.736393s
Time in Lock Server /Seconds     0.000000s

Error locking table TBTCO

Hi,
We are having issue in locking "Error locking table TBTCO" at our SM12 statics Maximum Number of Lock Owners     3603
Even on increasing the enque/table_size it not effecting the lock owner. Our environment having enq replication server.
The profile parameter for enque/serverinst = $(SCSID) (00)
enque replication server instance number is 10
What could be the correction need to be done?
Regards,
RMav

You have to check the reason for the error in the lock.
Get the Work Process number that logged the error in SM21. Check the trace file of this work proces. At the same timestamp of the error in SM21 you do find the root cause in the work process trace.
Usually this is caused by a overflow in the enqueue table, but not always. For this reason you have to check the work process trace the reasl root cause.
To check if the enqueue is suffering a overflow you should go to SM12 -> Extras -> Statistics
If in the statistics you do find that the "Maximum Fill Level" reached the maximum number of locks in these itens, for example:
Maximum Number of Lock Owners 39481
Maximum Fill level 458
Current Fill Level -25
Maximum Number of Lock Arguments 39481 <<<
Maximum Fill level 39480                                 <<<
Current Fill Level 15
Maximum Number of Lock Entries 39481    <<<
Maximum Fill level 39480                             <<<
this means that the enqueue was really suffering under an overflow situation.
Just for your information, the TBCTO is the table for the status of the jobs. So, every job need
to write the status in this table and also lock this table firstly.
Clébio

Lock table is out of available locker entries

My mail server version is -->
Sun Java(tm) System Messaging Server STORE 6.3-0.15 (built Feb 9 2007)
Not always this thing happened but sometimes, I can find follow error message in deault log file.
---- default log --
[12/May/2009:12:00:00 +0900] epajo01 imdbverify[4106]: General Notice: verify database snapshots started
[12/May/2009:12:00:00 +0900] epajo01 imdbverify[4106]: General Notice: verify snapshots finished: Total verified 3 Total failed = 0
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Notice: imexpire started, functions: expire purge
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Error: locking error: Lock table is out of available locker entries
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Error: DBERR: can't get locker id for file descriptor 20: Not enough space
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: Store Critical: Unable to lock index for user/journal_ms08_i: Not enough space
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Error: locking error: Locker does not exist
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: Store Error: locking {StoreRoot}/=user/02/91/=journal_ms08_i/store.exp: Invalid argument
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Error: locking error: Locker does not exist
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: Store Critical: Unable to lock index for user/journal_ms08_y: Invalid argument
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Error: locking error: Locker does not exist
-------- omit ---------
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: Store Error: locking {StoreRoot}/=user/e1/91/=journal_ms08_g/store.exp: Invalid argument
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Error: locking error: Lock table is out of available locker entries
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Error: locking error: Locker does not exist
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Error: DBERR: can't get locker id for file descriptor 23: Not enough space
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: Store Critical: Unable to lock index for user/journal_ms08_w: Invalid argument
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: Store Error: locking {StoreRoot}/=user/73/e5/=journal/store.exp: Not enough space
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Error: locking error: Locker does not exist
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: Store Error: locking {StoreRoot}/=user/e2/91/=journal_ms08_w/store.exp: Invalid argument
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Error: locking error: Locker does not exist
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: Store Critical: Unable to lock index for user/journal_ms08_h: Invalid argument
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Error: locking error: Locker does not exist
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: Store Error: locking {StoreRoot}/=user/f1/91/=journal_ms08_h/store.exp: Invalid argument
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Error: locking error: Locker does not exist
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: Store Critical: Unable to lock index for user/journal_ms08_x: Invalid argument
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Error: locking error: Locker does not exist
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: Store Error: locking {StoreRoot}/=user/f2/91/=journal_ms08_x/store.exp: Invalid argument
[12/May/2009:12:00:01 +0900] epajo01 imexpire[4115]: General Notice: Expire finished
When I can see this error message in default log files, all emails are enqueued but not dequeued.
Emails are just piled up in a queue directory, and getting increased.
To solve this thing, I just restart mail server(with stop-msg, start-msg command) and then emails are dequeued.
In a web site, I found those error messages can be found when some interrption occurred like Control-c in product using Berkeley DB .
I know JMS is using Berkeley DB but at that time there is no chance to use Control-c.
With those log, I just can assum imexpire started when snapshots job is not finished completely(although log file shows snapshots job is finished).
Imexpire started before snapshots not release locker
But I am not Sure.
I don't know why this thing happened and what is solid workaround.
If someone had the same problem as mine, plz reply
Thanks in advance.
Edited by: leeky41 on May 12, 2009 7:22 AM

leeky41 wrote:
Sun Java(tm) System Messaging Server STORE 6.3-0.15 (built Feb 9 2007) Please always provide the full output of ./imsimta version. I cannot tell for example what platform you are using (Solaris SPARC/x86/Linux).
I don't know why this thing happened and what is solid workaround.I suggest your first step is to upgrade to a recent release of MS6.3 and see if the problem persists.
Regards,
Shane.

Lock tables when load data

Are there any way to lock tables when i insert data with SQL*Loader? or oracle do it for me automatically??
how can i do this?
Thanks a lot for your help

Are there any problem if in the middle of my load (and commits) an user update o query data ?The only problem that I see is that you may run short of undo space (rollback segment space) if your undo space is limited and the user is running a long SELECT query for example: but this problem would only trigger ORA-1555 for the SELECT query or (less likely since you have several COMMIT) ORA-16XX because load transaction would not find enough undo space.
Data is not visible to other sessions, unless, the session which is loading data, commits it. That's the way Oracle handle the read committed isolation level for transaction.
See http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96524/c21cnsis.htm#2689
Or what happens if when i want to insert data someone has busy the table?You will get blocked if you try to insert data that has the same primary key as a row being inserted by a concurrent transaction.

MySQL lock table size Exception

Hi,
Our users get random error pages from vibe/tomcat (Error 500).
If the user tries it again, it works without an error.
here are some errors from catalina.out:
Code:
2013-07-31 06:23:12,225 WARN [http-8080-8] [org.hibernate.util.JDBCExceptionReporter] - SQL Error: 1206, SQLState: HY000
2013-07-31 06:23:12,225 ERROR [http-8080-8] [org.hibernate.util.JDBCExceptionReporter] - The total number of locks exceeds the lock table size
2013-07-31 06:23:12,242 WARN [http-8080-8] [org.kablink.teaming.web.portlet.handler.LogContextInfoInterceptor] - Action request URL [http://vibe.*******.ch/ssf/a/do?p_name=ss_forum&p_action=1&entryType=4028828f3f0ed66d013f0f3ff208013d&binderId=2333&action=add_folder_entry&vibeonprem_url=1] for user [kablink,ro]
2013-07-31 06:23:12,245 WARN [http-8080-8] [org.kablink.teaming.spring.web.portlet.DispatcherPortlet] - Handler execution resulted in exception - forwarding to resolved error view
org.springframework.dao.InvalidDataAccessApiUsageException: object references an unsaved transient instance - save the transient instance before flushing: org.kablink.teaming.domain.FolderEntry; nested exception is org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: org.kablink.teaming.domain.FolderEntry
at org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:654)
at org.springframework.orm.hibernate3.HibernateAccessor.convertHibernateAccessException(HibernateAccessor.java:412)
at org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:411)
2013-07-31 06:23:36,474 ERROR [Sitescape_QuartzSchedulerThread] [org.quartz.core.ErrorLogger] - An error occured while scanning for the next trigger to fire.
org.quartz.JobPersistenceException: Couldn't acquire next trigger: The total number of locks exceeds the lock table size [See nested exception: java.sql.SQLException: The total number of locks exceeds the lock table size]
at org.quartz.impl.jdbcjobstore.JobStoreSupport.acquireNextTrigger(JobStoreSupport.java:2794)
at org.quartz.impl.jdbcjobstore.JobStoreSupport$36.execute(JobStoreSupport.java:2737)
at org.quartz.impl.jdbcjobstore.JobStoreSupport.executeInNonManagedTXLock(JobStoreSupport.java:3768)
at org.quartz.impl.jdbcjobstore.JobStoreSupport.acquireNextTrigger(JobStoreSupport.java:2733)
at org.quartz.core.QuartzSchedulerThread.run(QuartzSchedulerThread.java:264)
Caused by: java.sql.SQLException: The total number of locks exceeds the lock table size
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:946)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2870)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1573)
at com.mysql.jdbc.ServerPreparedStatement.serverExecute(ServerPreparedStatement.java:1169)
2013-07-31 06:27:12,463 WARN [Sitescape_Worker-8] [org.hibernate.util.JDBCExceptionReporter] - SQL Error: 1206, SQLState: HY000
2013-07-31 06:27:12,463 ERROR [Sitescape_Worker-8] [org.hibernate.util.JDBCExceptionReporter] - The total number of locks exceeds the lock table size
2013-07-31 06:27:12,463 ERROR [Sitescape_Worker-8] [org.jbpm.graph.def.GraphElement] - action threw exception: Hibernate operation: could not execute update query; uncategorized SQLException for SQL [update SS_ChangeLogs set owningBinderKey=?, owningBinderId=? where (entityId in (? , ?)) and entityType=?]; SQL state [HY000]; error code [1206]; The total number of locks exceeds the lock table size; nested exception is java.sql.SQLException: The total number of locks exceeds the lock table size
org.springframework.jdbc.UncategorizedSQLException: Hibernate operation: could not execute update query; uncategorized SQLException for SQL [update SS_ChangeLogs set owningBinderKey=?, owningBinderId=? where (entityId in (? , ?)) and entityType=?]; SQL state [HY000]; error code [1206]; The total number of locks exceeds the lock table size; nested exception is java.sql.SQLException: The total number of locks exceeds the lock table size
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:83)
at org.springframework.orm.hibernate3.HibernateAccessor.convertJdbcAccessException(HibernateAccessor.java:424)
2013-07-31 06:27:22,393 INFO [CT-kablink] [org.kablink.teaming.lucene.LuceneProvider] - (kablink) Committed, firstOpTimeSinceLastCommit=1375251142310, numberOfOpsSinceLastCommit=12. It took 82.62174 milliseconds
2013-07-31 06:28:22,686 INFO [Sitescape_Worker-9] [org.kablink.teaming.jobs.CleanupJobListener] - Removing job send-email.sendMail-1375252102500
2013-07-31 06:29:51,309 INFO [Sitescape_Worker-10] [org.kablink.teaming.jobs.CleanupJobListener] - Removing job send-email.sendMail-1375252191099
2013-07-31 06:32:08,820 WARN [http-8080-2] [org.hibernate.util.JDBCExceptionReporter] - SQL Error: 1206, SQLState: HY000
2013-07-31 06:32:08,820 ERROR [http-8080-2] [org.hibernate.util.JDBCExceptionReporter] - The total number of locks exceeds the lock table size
2013-07-31 06:32:10,775 WARN [http-8080-1] [org.hibernate.util.JDBCExceptionReporter] - SQL Error: 1206, SQLState: HY000
2013-07-31 06:32:10,775 ERROR [http-8080-1] [org.hibernate.util.JDBCExceptionReporter] - The total number of locks exceeds the lock table size
2013-07-31 06:32:12,305 WARN [http-8080-1] [org.hibernate.util.JDBCExceptionReporter] - SQL Error: 1206, SQLState: HY000
2013-07-31 06:32:12,305 ERROR [http-8080-1] [org.hibernate.util.JDBCExceptionReporter] - The total number of locks exceeds the lock table size
2013-07-31 06:32:14,605 WARN [http-8080-3] [org.hibernate.util.JDBCExceptionReporter] - SQL Error: 1206, SQLState: HY000
2013-07-31 06:32:14,606 ERROR [http-8080-3] [org.hibernate.util.JDBCExceptionReporter] - The total number of locks exceeds the lock table size
2013-07-31 06:32:16,056 WARN [http-8080-3] [org.hibernate.util.JDBCExceptionReporter] - SQL Error: 1206, SQLState: HY000
2013-07-31 06:32:16,056 ERROR [http-8080-3] [org.hibernate.util.JDBCExceptionReporter] - The total number of locks exceeds the lock table size
2013-07-31 06:32:24,166 WARN [http-8080-1] [org.hibernate.util.JDBCExceptionReporter] - SQL Error: 1206, SQLState: HY000
2013-07-31 06:32:24,166 ERROR [http-8080-1] [org.hibernate.util.JDBCExceptionReporter] - The total number of locks exceeds the lock table size
2013-07-31 06:32:24,167 WARN [http-8080-1] [org.kablink.teaming.spring.web.portlet.DispatcherPortlet] - Handler execution resulted in exception - forwarding to resolved error view
org.springframework.jdbc.UncategorizedSQLException: Hibernate flushing: could not insert: [org.kablink.teaming.domain.AuditTrail]; uncategorized SQLException for SQL [insert into SS_AuditTrail (zoneId, startDate, startBy, endBy, endDate, entityType, entityId, owningBinderId, owningBinderKey, description, transactionType, fileId, applicationId, deletedFolderEntryFamily, type, id) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 'A', ?)]; SQL state [HY000]; error code [1206]; The total number of locks exceeds the lock table size; nested exception is java.sql.SQLException: The total number of locks exceeds the lock table size
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:83)
at org.springframework.orm.hibernate3.HibernateTransactionManager.convertJdbcAccessException(HibernateTransactionManager.java:805)
at org.springframework.orm.hibernate3.HibernateTransactionManager.convertHibernateAccessException(HibernateTransactionManager.java:791)
at org.springframework.orm.hibernate3.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:664)
It always logs the Mysql error code 1206:
MySQL :: MySQL 5.4 Reference Manual :: 13.6.12.1 InnoDB Error Codes
1206 (ER_LOCK_TABLE_FULL)
The total number of locks exceeds the lock table size. To avoid this error, increase the value of innodb_buffer_pool_size.
The value of innodb_buffer_pool_size is set to 8388608 (8MB) on my server.
In the documentation (MySQL :: MySQL 5.4 Reference Manual :: 13.6.3 InnoDB Startup Options and System Variables) it says that the default is 128MB.
Can i set the value to 134217728 (128MB) or will this cause other problems? Will this setting solve my problem?
Thanks for your help.

I already found an entry from Kablink:
https://kablink.org/ssf/a/c/p_name/s...beonprem_url/1
But i think this can't be a permanent solution...
Our MySQL Server version is 5.0.95 running on sles11

What exactly is the difference between enqueue,latch & lock

Can someone explain in simple words (with example if possible) what exactly is the difference between enqueue,latch & lock?
I have gone through documentation & other links,but just not able to figure out the exact & clear difference between these three..
Cheers,
Kunwar

In addition to links provided by Sb and nice explanations by Aman, i would like to add below :
1.Latches and enqueues are lightweight serialization devices used to coordinate multi-user access to
shared data structures, objects and files.
Latches are locks that are held for extremely short periods of time, for example the time it takes to modify
an in-memory data structure. They are used to protect certain memory structures, such as the database
block buffer cache or the library cache in the shared pool (as described in Chapter 2, Architecture). Latches
are typically requested internally in a ‘willing to wait’ mode. This means that if the latch is not available,
the requesting session will sleep for a short period of time and retry the operation later. Other latches may
be requested in an ‘immediate’ mode, meaning that the process will go do something else rather than sit
and wait for the latch to become available. Since many requestors may be waiting for a latch at the same
time, you may see some processes waiting longer than others. Latches are assigned rather randomly, based
on the ‘luck of the draw’, if you will. Whichever session asks for a latch right after it was released will get it.
There is no line of latch waiters, just a ‘mob’ of waiters constantly retrying.
Oracle uses atomic instructions like ‘test and set’ for operating on latches. Since the instructions to set
and free latches are atomic, the operating system itself guarantees that only one process gets it. Since it
is only one instruction, it can be quite fast. Latches are held for short periods of time and provide a
mechanism for clean-up in case a latch holder ‘dies’ abnormally while holding it. This cleaning up
process would be performed by PMON.
Enqueues are another, more sophisticated, serialization device, used when updating rows in a database
table, fro example. They differ from latches in that they allow the requestor to ‘queue up’ and wait for
the resource. With a latch request, the requestor is told right away whether they got the latch or not.
With an enqueue, the requestor will be blocked until they actually attain it. As such, they are not as fast
as a latch can be, but they do provided functionality over and above that which a latch can offer.
Enqueues may be obtained at various levels, so you can have many ‘share’ locks and locks with various
degrees of ‘shareability’.
Source:Expert Oracle Database Architecture by Thomas Kyte
2.Good PPT at http://nocoug.org/download/2001-05/latches.ppt
3.Good PPT by Mark bobak at http://www.mi-oaug.org/Presentations/Understanding%20Locks%20and%20Enqueues.ppt
HTH
Girish Sharma

Command object locks table (TX)

Im having locking probmlems with ODP.NET. Im updating same table with many connections in many threads. I get table locks for hours (over 24 hours) and I cant find any timout to set. The CommandTimeout on the Command object is not implemented.
In the V$Lock table I can see two locks on the same table made by two session ids from the same computer.
Im using transactions on the Connection object.
How do I set a timout for the update so that the lock will dissapear?
String connString = "Data Source="     + dsn + ";"
          + "User ID="          + user + ";"
          + "Password="          + pwd;
OracleConnection conn = new OracleConnection(connString);
String sql = "UPDATE ABDATA2 SET ABNAVN='SOLNA STAD ' WHERE OBJID = -21805738";
OracleCommand command = new OracleCommand(sql, m_conn);
//command.CommandTimeout = 60000; Exists but not supported
command.ExecuteNonQuery();
Is there anyone who has a clue?

Hi Neo, thanks for responding;
I did not publish the report with saved data, and I'm not sure what you mean about appending the string value? Could you explain that part?
The parameter I created is only declared as a string with no default value with a name of "CodeTableName". I used the Create paramter button you have in the Command object window to make it.
I then added the parameter name to my SQL statement as listed above.
The actual code table names in the database is actually longer then what the parameter calls for. They all start with "TIBURON.ZZ_" and end with "_Codes". I didn't want the users to have to remember the full names so that's why the SQL statement shows those additional parts.
The report works perfect when I'm running this report from Crystal Reports 9 or CR11 itself. It's only when I upload the report to our web server that the users isn't provided a prompt to enter a parameter. They only have button labed "Run Report".
Any ideas?
Thanks,
Joe

EnqStoreTopHist: Lock Table Overflow

Hello SAP agents,
This is the error log from our basis team. As I checked with SD users, they didn't do anything special in VT01N/VT02N and there are no big volumn in their shipment. Maximun there will be 70 items inside. This will not cause any tables locked.
Our basis team mentioned SAP Notes 1800487 and 604473, but we suppose that our system (ECC 6.0) is including them already.
Pls can you help us with this defect? It's very urgent!
2014-9-11:
EnqStoreTopHist: Lock Table Overflow at 2014/09/11 09:58:07 caused by
Top user 1:
Cnt=   89911 Cli=011 Uname=WOA9HK3      Tcode=VT02N
Owner1=20140911095734119086009474rb3prpa0........................
Owner2=20140911095734119086009474rb3prpa0........................
Top user 2:
Cnt=      82 Cli=011 Uname=DIM6CHA      Tcode=/REX/R_BININFO
   Owner1=20140911082516610788004574rb3prpa0........................
Owner2=20140911082516610788004574rb3prpa0........................
Top user 3:
Cnt=      47 Cli=011 Uname=YAE5PK       Tcode=MD15
Owner1=20140911082858843639001374rb3prpa0........................
Owner2=
2014-9-5:
EnqStoreTopHist: Lock Table Overflow at 2014/09/05 15:23:56 caused by
Top user 1:
Cnt=   89482 Cli=011 Uname=TSQ9HK3 Tcode=VT01N
   Owner1=20140905152159039144007174rb3prpa0........................
Owner2=20140905152159039144007174rb3prpa0........................
Top user 2:
Cnt=     218 Cli=011 Uname=LYA2PK       Tcode=MD15
Owner1=2014090508543029367200E374rb3prpa0........................
   Owner2=
Top user 3:
Cnt=     212 Cli=011 Uname=LYA2PK       Tcode=MD15
Owner1=2014090513464980597800H074rb3prpa0........................
Owner2=2014090513464980597800H074rb3prpa0........................
Top argument 1:
No top lock argument 1 identified
Top argument 2:
No top lock argument 2 identified
Top argument 3:
No top lock argument 3 identified
EnqStoreTopHist: Lock Table Overflow at 2014/09/05 15:57:43 caused by
Top user 1:
Cnt=   89741 Cli=011 Uname=TSQ9HK3      Tcode=VT01N
   Owner1=20140905152159039144007174rb3prpa0........................
Owner2=20140905152159039144007174rb3prpa0........................
Top user 2:
Cnt=     218 Cli=011 Uname=LYA2PK       Tcode=MD15
Owner1=2014090508543029367200E374rb3prpa0........................
   Owner2=
Top user 3:
Cnt=      36 Cli=011 Uname=PAM8AHM      Tcode=ME21N
Owner1=20140905143700719131005374rb3prpa0........................
Owner2=20140905143700719131005374rb3prpa0........................
Top argument 1:
No top lock argument 1 identified
Top argument 2:
No top lock argument 2 identified
Top argument 3:
No top lock argument 3 identified

Hello,
Not on apps servers but on CI/enque server
enque/table_size in ASCS/CI
http://help.sap.com/saphelp_nw04/helpdata/en/37/a2e3ab344411d3acb00000e83539c3/content.htm
Enque/table_size paramter is not reflecting in SM12 statistics
http://help.sap.com/saphelp_nw04/helpdata/en/fd/c675698b8d462b8895583c27bdc9bd/content.htm
Thanks

Insert & Update while Locking tables

Update & Insert
Is it possible for me to insert a record and update 2 fields in another record, whil locking the database tables for the process to take place?
If so, how?
Thanks
Pete

I don't know which database server you are using. But in MySQL, you can do something like this:
<?php
function get_next_number( $field = 'id' )
     $id = 0;
     //Lock the table for write
     mysql_query('LOCK TABLES name_of_table WRITE');
     $sql = 'SELECT '.$field.' FROM name_of_table ORDER BY '.$field.' DESC LIMIT 1';
     $query = mysql_query($sql);
     if ( mysql_num_rows($query) > 0 )
          $row = mysql_fetch_row($query);
          //Get the $field value
          $id = $row[0];
     //Unlock tables
     mysql_query('UNLOCK TABLES');
     return ++$id;
?>
I didn't test this function, but the idea is that
Check if you are connected to MySQL server
Regards,
Rafael

Lock table overflow in SAP

We are tyring to execute a transaction and it is giving the error Lock table overflow, Though the enque/table_size parameter is set to 96,000 KB which i guess good enough.
Can you please suggest.
Thanks,
Chandu

Hello Chandu,
how many records this transaction is locking?
SAP Note 746138: Analyzing lock table overflows, describes how to analyze this issue.
Are you using Standalone enqueue? If that's the case check that the enqueue table size is defined in the ASCS instance.
kind regards,
Mercedes

Enqueue server question

I was wondering i someone can help me by answering the following question:
In the enqueue server, do you receive a exception in the following scenarios?
1.You try to read a object/item which is already being read by other resource?
2.You try to write a object/item which is already being read by other resource?
3.You try to read a object/item which is already being written by other resource?
Thanks for your help

Hi John,
So, it depends e.g. on the type of lock that is acquired. For more information please check the <a href="http://help.sap.com/saphelp_nw04/helpdata/en/f4/670f9b9d62f94db4ea7361b34ea214/frameset.htm">Enqueue Server documentation</a>.
HTH!
-- Vladimir

Enqueue Server Lock Table

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