Re: Help with a DEAD LOCK error

A copy of this was sent to Nnoor_at_cris.com (NNOOR) (if that email address didn't require changing) On 14 Dec 1998 08:54:31 PST, you wrote:

>
>Oracle 7.3.3 + WinNT4(sp3). Was running on a HP Server machine. Have
>transferred to a HP workstation for a few days as the server is
>getting RAD cards and extra CPU's put in.
>
>Application was running fine and now all of a sudden we get following
>error---has happened twice, each time time with a *different* table
>name in the error message.
>
>*** 1998.12.10.15.49.18.281
>*** SESSION ID:(22.15743) 1998.12.10.15.49.18.281
>A deadlock among DDL and parse locks is detected.
>This deadlock is usually due to user errors in
>the design of an application or from issuing a set
>of concurrent statements which can cause a deadlock.
>This should not be reported to Oracle Support.
>The following information may aid in finding
>the errors which cause the deadlock:
>ORA-04020: deadlock detected while trying to lock object MMS.TASK_ACCOUNT
>
>
>Could "smaller" machine be the cause of it? Could we have screwed up
>when importing and exporting DB between the two machines? Any ideas?
>

this could be caused by massive amounts of invalid objects in the database. When a procedure is imported into a fresh instance -- it typically ends up being invalid. Over time, as the procedures in your database get used, they will recompile themselves.

What *might* be happening is that an infrequently used procedure is just getting compiled for the first time. It is attempting to get some parse locks on objects to compile itself. It is failing since someone else has some conflicting lock on the referenced table/procedure/database object at the time you are compiling...

Its definitely not fatal as the compilation typically succeeds the next time around and won't happen again unless the object becomes invalid later for some other reason.

You can use dbms_utility.compile_schema to recompile invalid objects in a schema but its not really necessary.

>Thanks very much for your help!
>
>Regards,
>Nasir Noor (nnoor_at_cris.com)
 

Thomas Kyte
tkyte_at_us.oracle.com
Oracle Service Industries
Reston, VA USA

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