Table Row Frequent Lock

Dear All,
Recently we had changed our remote connection from 128KB Leased Line to high speed IP VPN (1MB) MPLS based lines. After that onwards Oracle table rows are getting locked frequently. We are using Windows 2003 Server Std with 9i 2.0.7 database loaded. Server Total Memory is 4GB with 3.2 MHz dual processor.
When we increase the sga_max_size (1400MB or above), ORA-12500:TNS:Listener failed...... error appears and users can't connect to our database server.
Memory Configuration is:-
Shared Pool - 352MB
Buffer Cache - 584MB
Large Pool - 128MB
Java Pool - 16MB
SGA Max Size - 1281.573 MB
Aggregate PGA Target - 259MB
Please help to correctly calculate the Memory configuration if its wrong. Or is there any other solution to sort out the table row locking problem.
Thanking you all in advance,
Manesh

On initial guess, it sounds like you are chasing the wrong aspect of the problem.
You do not describe what the application is doing, but logically it appears that you are getting more transactions happening because of the higher access speed. In other words, the client is no longer being throttled back.
You also do not decribe the actual kind of lock. It intrigues me that specific rows would need to be locked - that implies that the application is attempting to capture the rows ahead of time. This sort-of feels like the application may have been ported from another system, or designed based on a totally different locking machanism that what Oracle usess, forcing Oracle to try to work in a way it is not supposed to work.
Simply throwing more resources at the problem will [probably] not solve the problem - it may alleviate it for a while. Better would be to understand what is actually happening and correct the root cause.
I encourage you to read Tom Kyte's "Expert Oracle Database Architecture: 9i and 10g Programming Techniques and Solutions" to get some tools to help undertsnad and isolate the actual problem. (http://apress.com/book/bookDisplay.html?bID=10008)
As for the ORA-12500, I believe Metalink has a few notes about that.

Similar Messages

Locked objects, Locked rows in a table, kind of locks

Well, final question for the day.
I created multiple session using sql plus, and in one session sql plus got lunch, it hour glasses and does nothing. I called up a DBA friend and he opined that it might be becasue one of my sessions has got a lock on a row in a table. I was also told that locks can be table level locks and row level locks.
Please help me understand the below( I did try to read about locks, but atleast after first reading it is more confusing.. in order to update a row in a table why would oracle obtain a table level lock?)
1. What are the different database objects which can get locked ?
2. What are the different kinds of locks and what do they mean?
3. When a row is locked by a session, can we identify that particular session and how ?
4. What is the difference between pessimistic locking and optmistic locking ?
5. Any scripts which I can use to get lock related info from database ?
Gony

1. What are the different database objects which can get locked ?There are locks which oracle acquire on any useful resource. We , as the users are most focussed on tables and their locks. But locks do happen in memory as well.
2. What are the different kinds of locks and what do they mean?http://download.oracle.com/docs/cd/B28359_01/server.111/b28320/dynviews_2.htm#REFRN30121
3. When a row is locked by a session, can we identify that particular session and how ?Sure, there is a default script that comes up, utllockt.sql which can show you. Other than that, you can EM to do so as well. Read this,
4. What is the difference between pessimistic locking and optmistic locking ?http://download.oracle.com/docs/cd/B28359_01/server.111/b28274/instance_tune.htm#sthref748
5. Any scripts which I can use to get lock related info from database ?See #4 above.
HTH
Aman....

GTT table getting Row Exclusive lock

I have a procedure which loads a table which is used for reporting.
Currently it is a single process which picks up most of the data after joining 2-3 big tables(around 70-80GB) and then loading the main table.
The joins are on PI and also partitions are also being used. Then a lot of updates are done on the main table to update other columns which are being picked from different tables.
As the processing is happening on huge amount of data(around 1M), so processing is taking a lot of time.
This process is taking around 40-45 minutes.
I am planning to use parallelism to run it in 75 sessions. So the initial big insert will be faster and later on all the updates will be done on smaller chunks which will benefit the performance.
I planned to use GTT table so that i dont have to create 75 temp tables for each sessions.
But while using GTT table(ON COMMIT DELETE ROWS) in parallel sessions, i am seeing that the GTT table is getting Row Exclusive lock and the time taken by overall process is increasing by lot.
So i tested by using 75 temp tables. There i saw that the performance has increased by lots as assumed initially.
Please let me know if there is any other way or how to remove the locks on GTT table.

First you should question why you think you need 75 GTT.
Also your question contains no useful information
(no four digit version of Oracle, no OS, no number of processors) , this paragrah
Currently it is a single process which picks up most of the data after joining 2-3 big tables(around 70-80GB) and then loading the main table.
The joins are on PI and also partitions are also being used. Then a lot of updates are done on the main table to update other columns which are being picked from different tables.
As the processing is happening on huge amount of data(around 1M), so processing is taking a lot of time.
This process is taking around 40-45 minutes.tells nothing,
so basically your questions boils down to
- Hey I come from a sqlserver background (this is just an educated guess), how can I find a workaround to wreck Oracle to make it work like sqlserver.
75 parallel sessions on say 4 to 8 processors is a very bad idea, as these sessions will be simple competing for resources.
Also a row exclusive lock is just that: a row level lock. This isn't a problem, usually.
Sybrand Bakker
Senior Oracle DBA

Table row lock problem

Dear Oracle Tech.
As end user of Oracle Database, we seek advise from Oracle on the following issue :
Our business application is an OLTP system and currently we have an adhoc batch process that needs to be executed. This batch process mirrors a normal online user process in the way some tables are updated on the database. Our concern arises when our customer requested to run the batch process during normal office hours which actually is not the norm. We would like to have your opinion on running batch update process during normal office hours, are there issues of lock contention and risk of deadlock? We understand Oracle databases have lock mechanisms built into it but is there a risk of the deadlock situation arising if we do execute the batch process during normal office hours? And if deadlock does occurs, how easy is it to detect and resolve the deadlock and return the application to normal operation?
Our database is Oracle 7.3.4 running on Solaris 2.6 over a network, our online application is built with PowerBuilder 7 and running on Windows95 clients.
Thank You.

Hi,
fortunately Oracle tries by default to minimize all locking issues on its objects, only those rows are locked(until a commit or rollback occurs),which are modified by transactions, table locking will normally not happen. This is very appropriate and works well for OLTP applications. But, indeed, concurrent batch operations with bulk data loading could produce problems. In general, because of their resource consumption and also because of growing locking issues. Consider this example:
You have (in your batch procedure) an update statement, which updates a complete table.
UPDATE big_table SET field1 = anything;
no WHERE clause reduces the affected rows.
When this update has been started, all affected rows are locked, this may be many and the transaction will last for a long time, no other user can update (or delete) any of these rows. This issue is not resolved, until a commit or rollback occurs.
Deadlocks are relatively rare and are selfdetected and resolved by oracle (the blocking transaction will be rollbacked). You will find an entry in the alert log and a trace file is produced.
I'm not familiar with PowerBuilder, but I know sometimes Oracle's default locking methods are overwritten by third party software.
Regards
Werner

Locked table row

I would like to identify the user who has a specific table row locked from another user who initiates a SELECT ... WHERE ROWID = ... FOR UPDATE ON ... NOWAIT. Is it possible to determine who has that lock?

You can first select holding_session, waiting_session from dba_waiters.
Using these find the username , osuser from v$session where sid=holding_session or
sid=waiting_session
<BLOCKQUOTE><font size="1" face="Verdana, Arial, Helvetica">quote:</font><HR>Originally posted by C. Fetter ([email protected]):
I would like to identify the user who has a specific table row locked from another user who initiates a SELECT ... WHERE ROWID = ... FOR UPDATE ON ... NOWAIT. Is it possible to determine who has that lock?<HR></BLOCKQUOTE>
null

Table/row locking

Hi Guys,
Is this related to db size table/row locking?
thanks
version: 10.2.0.5
at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:183)
org.exolab.castor.jdo.LockNotGrantedException: persist.writeLockTimeoutcom

dbaing wrote:
Hi Guys,
Is this related to db size table/row locking?
thanks
version: 10.2.0.5
at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:183)
org.exolab.castor.jdo.LockNotGrantedException: persist.writeLockTimeoutcomrow locking is 100% & totally independent of table size or number of rows in the table.
java stack dump is borderline meaningless.
You need Oracle error number & message to determine root cause.

Pl sql row level locking with wait ?

Hi,
I am using oracle 10g.
I am new to Oracle locks. I have two tables Table1(id_no, employee, salary) and Table2(id_no, employee, salary).
I need to pull any requested row from Table1 into Table2 only once on demand. I have a procedure to pull data and there could be more than one requests try to call same procedure to pull a row from Table1 into Table2 at any given time.
I coded below to achieve row level lock. if one transaction gets row level lock on Table1 at 2, so other Transactions should wait till the lock is released at line 2 or 5 to avoid duplicates.
But below code is not working, I am getting duplicates when I call this using two concurrent java threads.
How do I control this concurrency issue so that I can avoid duplicate entries in Table2. Could any one please help?
1.begin
2.select 0 into emp_cnt
3.from Table1 where id=id_no
4.for update;
5.update Table1 set employee='xyz'
6.where id=id_no;
7.select count(*) into table2_cnt from Table2 where id=id_no;
8.if(table2_cnt =0) then
9.code to insert above row from Table1 to Table2;
10.end if;
11.commit;
12.End;
Edited by: 980916 on Jan 9, 2013 5:48 PM

Welcome to the forums and welcome to Oracle.
Lets establish one thing right from the beginning ... the Oracle Database is not a Microsoft product.
There is no general reason to use row level locks, you should not want to use row level locks, you don't need row level locks, and you will almost never have any valid reason to consider row level locks.
That said there are two situations were it may be necessary to lock a row prior to an update or delete (possibly in a merge) and in those cases you want to use the built-in SELECT FOR UPDATE syntax. (Demo here: http://www.morganslibrary.org/reference/deadlocks.html#dlfu). But we should be clear here ... one rarely needs to use this locking mechanism as the chances of a collision in a well designed application are essentially zero.
Also as you are new to Oracle please explore the dynamic performance view V$RESERVED_WORDS and do not name objects, columns, etc. with reserved word names not that there is an excuse in any product to name a column "ID." Something Joe Celko has railed about for decades and a tradition I think we should all follow.
In the case of your posted code example (btw please read the FAQ and learn how to use tags) the solution is SELECT FOR UPDATE if locking can be justified which is unlikely.
Edited by: damorgan on Jan 9, 2013 6:11 PM

Row level locks

Hi All,
Version - Oracle Database 10g Enterprise Edition Release 10.2.0.2.0
I have a card's data in a table. Whenver a two different sessions/threads selects the data sometimes they get the same card.
Now I need to lock the record. If Thred-1 selects then it will lock the first records and thread-2 must select the second record as the first record is locked by thread-1.
I have written a piece of code , at first session it locks one record and when second session select it selects no records.
I have takem MIN group function because I want the cards to be selected in order.
Can you please tell where is my code went wrong or need some changes. Data and code is given below.
SQL> SELECT * FROM crm_pps_cards_sz ORDER BY 1;
CARD_NO          PIN SERIAL_NUMBER DATE_CREATED DATE_MERGED DATE_ALLOCATED DATE_REGISTERED
6338079966430591 9985 9950013661    12/06/2011
6338079973369543 6858 9950013660    12/06/2011
6338079978994154 7144 9950013655    12/06/2011
6338079981471778 7631 9950013654    12/06/2011
6338079986365041 7849 9950013657    12/06/2011
SQL>
Thread - 1
Connected to Oracle Database 10g Enterprise Edition Release 10.2.0.2.0
Connected as crm
SQL> set serveroutput on
SQL>
SQL> DECLARE
2    l_rec crm_pps_cards_sz%ROWTYPE;
3    CURSOR c IS
4      SELECT * FROM crm_pps_cards_sz t WHERE t.card_no =
5      (SELECT MIN(card_no) card FROM crm_pps_cards_sz)
6      FOR UPDATE NOWAIT SKIP LOCKED;
7
8 BEGIN
9    OPEN c;
10    FETCH c
11      INTO l_rec;
12    CLOSE c;
13    dbms_output.put_line('Card Allocated ' || l_rec.card_no);
14
15 END;
16 /
Card Allocated 6338079966430591
PL/SQL procedure successfully completed
SQL>
Thread - 2
Connected to Oracle Database 10g Enterprise Edition Release 10.2.0.2.0
Connected as crm
SQL> set serveroutput on
SQL>
SQL> DECLARE
2    l_rec crm_pps_cards_sz%ROWTYPE;
3    CURSOR c IS
4      SELECT * FROM crm_pps_cards_sz t WHERE t.card_no =
5      (SELECT MIN(card_no) card FROM crm_pps_cards_sz)
6      FOR UPDATE NOWAIT SKIP LOCKED;
7
8 BEGIN
9    OPEN c;
10    FETCH c
11      INTO l_rec;
12    CLOSE c;
13    dbms_output.put_line('Card Allocated ' || l_rec.card_no);
14
15 END;
16 /
Card Allocated
PL/SQL procedure successfully completed
SQL> My concern is that it must allocate in the order
6338079966430591
6338079973369543
....

It is because MIN(ard_no) is able to find value from table which is locked by you thread 1 and thread 1 mentioned NOWAIT thus it thread 2 went out without getting anything.
Please check my reply to your duplicate thread "row level locking" .

ORA-20001: The current row is locked

Hi Team
I find below mentioned error message in my log table .Please can you suggest why we are getting this error .
Some time back we had our OS migration from one server to another ,can it be related to that as we have noticed this error message after such migration.
Please suggest what can be done in order to avoid such error.
ERROR IN hr_person_api.update_person api failed -step4 -ORA-20001: The current row is locked
Cause:        You are trying to lock a row in the per_people_f table which is currently being locked by another user.
Action:        Re-query and attempt to lock the row again
ERROR IN hr_assignment_api.update_emp_asg API - STEP8.2 - ORA-20001: The current row is locked
Cause:        You are trying to lock a row in the per_all_assignments_f table which is currently being locked by another user.
Action:        Re-query and attempt to lock the row again.
Regards
Anima

Hi Everyone
Can anyone help me with this .Why we are getting this error and how can it be handled.
Please suggest what can be done in order to avoid such error.
ERROR IN hr_person_api.update_person api failed -step4 -ORA-20001: The current row is locked
Cause:        You are trying to lock a row in the per_people_f table which is currently being locked by another user.
Action:        Re-query and attempt to lock the row again
ERROR IN hr_assignment_api.update_emp_asg API - STEP8.2 - ORA-20001: The current row is locked
Cause:        You are trying to lock a row in the per_all_assignments_f table which is currently being locked by another user.
Action:        Re-query and attempt to lock the row again.

Detail screen for row level locking

Hi All ,
I have developed row level locking for a table , Next requirment is to display the details of each row i another screen when the user click on each row .And if the row which is clicked for display is geyout in first screen then it should be grey in details screen also .If the row is editable in the first screen then it should be in change mode in details screen .
I appreciate the help and support .
please provide the answer as soon as possbile .....
Thanks,
NJ

Yes, if a process holds many row level locks on a table, those locks by default can be escalated to partition locks, and, if necessary, table locks. Unless you are getting and holding many locks on a given table, this will not happen.
You say you are exporting data. If all you are doing is selecting from the table (not updating, deleting or inserting data) and you are using the read committed transaction isolation level, you would only hold a lock on a row for the small fraction
of a second when you are actually reading it. So you will never have large numbers of locks at one time. If you are doing large numbers of updates, inserts, or deletes in a singletransaction or if you are doing large numbers of selects in a single
transaction with the isolation level set to repeatable read or serializable, then it is possible to get enough locks to cause SQL server to escalate to partition or table locks. This is normally a good thing (that's the reason Microsoft made it the default).
To many locks eats up memory.
However, if you determine this is causing you a problem and you do not want the locks on a particular table ever escalated, you can use the ALTER TABLE SET (LOCK_ESCALATION = DISABLE) command to prevent most cases of lock escalation on a table by table basis.
See BOL for a description of the ALTER TABLE command. However, I would recommend you not use this unless you have determined that lock escalation is causing you problems. It is very easy to make things worse, not better by doing this.
Tom

Row Level Locking while inserting a record.

It is a good practice to lock the whole table or do the row level locking while performing any DELETE / UPDATE / MODIFY actions on a database table. Is it necessary to do the same thing while inserting a record via INSERT statement?
One point may arise if two users are inserting same records at a same time....
Well i am little bit confused here bcos if a record doen't exist in a table what is the point of locking it.
Please help me.

create a lock object using SE11 for that perticular table and include field names in Lock parameters. Then it will generate two FMs one for locking and another for unlocking.
Call the lock FM before updating the table and pass that row key value(For fields which taken in lock parameters for creating lock objects) to the exporting parameters.
Then do the updation.
Reward if useful...................

View a single table-row as multiple rows in a GridControl

Hi,
is it possible to distribute the entries of a single row of a table/RowSetInfo over multiple lines of a GridControl?
I've seen an example on the Internet (http://www2.gol.com/users/tame/swing/examples/JTableExamples4.html) which does this without database connection but it seems as if it's necessary to replace the default JTable, TableModel and UI by customized ones. As far as I've seen it's not possible to replace the JTable which is used by a GridControl? So is there any other way to do this? (A modification of the JTable-UI itself doesn't suffice as the JTable yields wrong row- and column-numbers on mousclick-events and therefore the components of the second row are not enabled properly).
Thanks in advance
null

|I've seen an example on the Internet |(http://www2.gol.com/users/tame/swing/exampl|es/JTableExamples4.html) which does this |without database connection but it seems as |if it's necessary to replace the default |JTable, TableModel and UI by customized |ones.
You wont be able to replace the JTable. But you can change all the attributes on the internal table which the grid uses (see getTable() method). The datamodel for the grid is impemented by oracle.dacf.control.swing.GridDataSource. You can possibly extend this class. You can also change the Table column model and the renderers used by the Table.
|So is there any other way to do this? (A |modification of the JTable-UI itself doesn't |suffice as the JTable yields wrong row- and |column-numbers on mousclick-events and |therefore the components of the second row |are not enabled properly).
Could you expain how the mapping between cell renderer and the table (row, col) is done in the extended JTable - which class ?.
(http://www2.gol.com/users/tame/swing/exampl|es/JTableExamples4.html)
null

Opening a new view in a new window on click of a table row entry.

Hi Guys,
How to open a new View of a same application in a new window (just like a pop up) on a click of a Table Row entry?
I am using NWDS 7.0 version. So please suggest acccorrdingly.

Hi Nikesh,
first of all you will have to declare use of onLeadSelect event handler for your table (note that it will only be triggered when a lead selection occurs not a multiselection).
Also, you can build at design time a View and a Window (for example, PopupWin) in your WebDynpro Component, and embed the view into the window.
In your code for onLeadSelect function, you can use something like this to pop up the window.
public void onActionRowSelection(com.sap.tc.webdynpro.progmodel.api.IWDCustomEvent wdEvent )
    //@@begin onActionSeleccionTabla(ServerEvent)
    IWDWindowManager windowManager = wdComponentAPI.getWindowManager();
    IWDWindowInfo windowInfo = wdComponentAPI.getComponentInfo().findInWindows("PopupWin");
    IWDWindow window = windowManager.createModalWindow(windowInfo);
    window.setWindowPosition(WDWindowPos.CENTER);
    window.setWindowSize(new WDCssSize(450, WDWindowUnitOfLength.PX) , WDCssSize.UNDEFINED);
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    wdContext.currentContextElement().setPopup(window);
    window.show();
    //@@end
Hope it helps,
David

I am getting frequent lock-ups and blue screens during boot up. The lock ups occur during normal use and I cannot click anything or force quit. The cursor shows something is loading, but never stops. I have to use power button. Ideas?

I am getting frequent lock-ups and blue screens during boot up on my Mac Pro. The lock- ups occur sometimes during normal use and I cannot click anything or force quit. The cursor shows something is loading, but never stops. I have to use power button.
I had the Mac Defender malware and I have used apple jack but still having issues.

I am getting frequent lock-ups and blue screens during boot up on my Mac Pro. The lock- ups occur sometimes during normal use and I cannot click anything or force quit. The cursor shows something is loading, but never stops. I have to use power button.
I had the Mac Defender malware and I have used apple jack but still having issues.

How to pass hidden field values on a click of a table row

hi all,
href = "bookAndNonBook.do"
I am very new to struts. I have created a table using displaytable tag which displays results in a tabular format. In addtion, i have a hidden field (prodType), the table rows are getting highlighted when i get my mouse on a particular row.
Following is the code from the results.jsp file
<body
onload="addRowHandlers('row', 'rowMouseOver')"
bgcolor="#FFFFFF" text="#000000" leftmargin="100" topmargin="50"
marginwidth="" marginheight="" rightmargin="30">
<html:form action="/bookAndNonBook" method="post">
<display:table name="sessionScope.productSearchList" id="row"
sort="list" export="true" defaultsort="1" defaultorder="ascending"
pagesize="15" decorator="org.displaytag.decorator.TotalTableDecorator"
class="dataTable">
<display:column property="prodType" title="ProdType" class="prodType"
headerClass="prodType" media="html" />
<display:column title="Title" property="titleName" sortable="true"
class="title" headerClass="title" />
</display:table>
</html:form>
</BODY>
I am calling a funtion addRowHandlers which passes the table id (which is row) and the rowMouseover for highlighting the rows on mouse over.
the code for function addRowHandlers is
function addRowHandlers(tableId, rowClassName) {
var previousClass = null;
var table = document.getElementById(tableId);
var rows = table.getElementsByTagName("tr");
for (i = 1; i < rows.length; i++) {
rows.onmouseover = function () {
previousClass = this.className;
this.className = this.className + " " + rowClassName ;
this.style.cursor="hand";
rows.onmouseout = function () {
this.className = previousClass;
this.style.cursor='';
rows.onclick = function (){
var cell = this.getElementsByTagName("td")[0];
var ProdType = cell.innerHTML;
alert("value of prodType = " + ProdType);
when i run the above code and click on a particular row it returns me the value in the hidden field i.e. prodType for that particular row
Now where i am having problem is i want that on the basis of prodType my jsp file should call different actions for different prodType as returned....somwhat a function like this
function submitProduct(prodType) {
if(prodType == "BK")
resultsForm.action = "/bookProduct.do";
else if(prodType == "NB")
resultsForm.action = "/nonbookProduct.do";
but i am unable to figure out that how do i this..
Any help will be really appreciated
Thanks
Sam

can you please suggest some good struts forums where i can post my question
thanks in advance
Sam

Table Row Frequent Lock

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