Re: Deadlock Detection

From: <Riyaj_Shamsudeen_at_i2.com>
Date: Fri, 22 Jun 2001 10:14:41 -0700
Message-ID: <F001.00333F70.20010622101657@fatcity.com>

Hi Anita
        If it is an ITL problem, then the resource type would be TX instead of DX. If the ITL table is full then the process requesting an ITL entry in that block will randomly select one of the transaction holding an ITL entry and wait for that process to complete or rollback. Since the process will wait for a transaction and as you are well aware of, the transaction id is a slot in a rollback segment and hence the enqueue type would be TX. Since this trace indicates that it is a DX type enqueue I would incline to think that this is a distributed transaction problem. Feel free to correct me if I am missing something..

Thanks
Riyaj "Re-yas" Shamsudeen
Certified Oracle DBA
i2 technologies   www.i2.com

"A. Bardeen" <abardeen1_at_yahoo.com>
Sent by: root_at_fatcity.com
06/22/01 10:50 AM
Please respond to ORACLE-L

        
        To:        Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
        cc:        
        Subject:        Re: Deadlock Detection

Tom,

The information you need should be in the trace file, but it's not in the excerpt you've listed, but the true problem is listed:

> Rows waited on:
> Session 27: no row

"No row" indicates that the deadlock is due to a lack of available ITL slots in the datablock.

Unfortunately resolving this requires recreating the object with either a high initrans value (to explicitly reserve space for more ITL slots) or a higher pctfree value (to give the ITL table more room to grow).

Depending on the application it could also be that multiple sessions are acquiring the same block off the free list so using multiple free lists could also help.  Starting with 8.1.6 this setting can be changed dynamically; prior to that you must recreate the object.

Note: 62365.1 also has some good info

HTH,

• Anita
  • "Mercadante, Thomas F" <NDATFM_at_labor.state.ny.us> wrote:
    > All,
    >
    > My current application (still under development) is
    > experiencing Oracle
    > deadlock problems.  The applications people are
    > performing stress testing
    > where the application is being repeatedly called
    > simulating actual users
    > hitting the database.
    >
    > The application is written using VB thru ADO and
    > COM, Oracle 816 on NT.
    >
    > My problem is that, while I can review the trace
    > file produced, I can't
    > figure out what the actual deadlock is occurring on.
    >  I have seen deadlock
    > trace files that clearly state "table blah", but in
    > this case, I get:
    >
    >
    > *** 2001-06-21 14:32:03.841
    > *** SESSION ID:(27.31211) 2001-06-21 14:32:03.810
    > DEADLOCK DETECTED
    > Deadlock graph:
    >                        ---------Blocker(s)--------
    > ---------Waiter(s)---------
    > Resource Name          process session holds waits
    > process session holds
    > waits
    > DX-0000003b-00000000        22      18     X        
    >     24      27
    > X
    > session 18: DID 0001-0018-0000003C                 session 27: DID
    > 0001-0018-0000003C
    > Rows waited on:
    > Session 27: no row
    > *** 2001-06-21 14:32:03.857
    > ksedmp: internal or fatal error
    > ORA-00060: deadlock detected while waiting for
    > resource
    >
    > Is there something like TKPROF that will process the
    > trace file and give me
    > more info on what is happening?  It looks like I am
    > waiting for a resource
    > to be freed, but which one is the question.
    >
    > thanks for any help.
    >
    > Tom Mercadante
    > Oracle Certified Professional
    >
    > --
    > Please see the official ORACLE-L FAQ:
    > http://www.orafaq.com
    > --
    > Author: Mercadante, Thomas F
    >   INET: NDATFM_at_labor.state.ny.us
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Received on Fri Jun 22 2001 - 12:14:41 CDT