How and when the database release a row lock?

Dear experts,
We are using the following statement to obtain a row lock in a table in the database(ORACLE of course),
SELECT * FROM {TABLE_NAME} WHERE ID = 1 for update
and if we succeed grabbing the row lock we will continue to issue a update statement every 30 seconds to preserve the lock as far as possible.
here is the update statement to preserve the lock,
UPDATE {TABLE_NAME} SET time = ? WHERE ID = 1.
As you see more longer we keep holding the row lock , more update statements are submitted in the pending transaction.
In normal case our application can grab the exclusive row lock and works for a long time,however sometimes a connection reset exception is thrown
and our application will close the connection(I assume the pending transaction will be rolled back by the database) and exit the JVM.
Since other applications will keep trying to grab the same row lock to become the master role,
we expect one of them can succeed but they are all failed because the database has not released the row lock as expected.
Can someone explain more details about how and when the row lock can get released in our use case?
Thanks,
SuoNayi
Edited by: SuoNayi on 2013-5-30 上午8:12

Hm. Is this part of an XA transaction by any chance? I know that Oracle maintains separate bookkeeping for such transactions which can cause rows to stay 'locked' even when the regular DBA views will indicate there is no user currently locking the record at all. I have no idea about the actual details and what you need to do to clean up such a situation, that is something a DBA should know and do.
If not... well this is more of a question for people who know the DBMS, which makes it a target for the Oracle DBMS forums. Java developers don't tend to have DBA-level knowledge of the database, you should ask the question where you have more chance of people with expertise answering stuff:
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"nelsons" wrote in message
news:[email protected]...
> how do I create a 1d array that takes a single calculation and insert
> the result into the first row and then the next calculation the next
> time the loop passes that point and puts the results in thsecond row
> and so on until the loop is exited.
>
> The attached file is work inprogress, with some dummy data sp that I
> can test it out without having to connect to equipment.
> The second tab is the one that I am having the problem with. the
> output array from the replace element appears to be starting at the
> index position of 1 rather than 0 but that is ok it is still show that
> the new data is placed in incrementing element locations. However the
> main array that I am trying to build that is suppose to take each new
> calculation and place it in the next index(row) does not appear to be
> working or at least I am not getting any indication on the inidcator.
>
> Basically what I am attempting to do is is gather some pulses from
> adevice for a minute, place the results for a calculation, so that it
> displays then do the same again the next minute, but put these result
> in the next row and so on until the specifiied time has expired and
> the loop exits. I need to have all results displayed and keep building
> the array(display until, the end of the test)Eventually I will have to
> include a min max section that displays the min and max values
> calculated, but that should be easy with the min max function.Actually
> I thought this should have been easy but, I gues I can not see the
> forest through the trees. Can any one help to slear this up for me.

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