Re: Can a deferred FK constraint cause "enq: TX - row lock contention" in Share (4) mode?

thanks for your answers.

> One scenario I've created which matches one set of your symptoms:
>
> Foreign key is deferrable initially deferred.
> Session 1 inserts a new parent key value - without commiting.
> Session 2 updates a child row changing a value that exists in the parent table to the new, uncommitted, parent value.
>
> Session 2 goes into TX mode 4 waiting for session 1 to commit; showing -1 as the current_obj#

I will need to discuss with the developers how exactly the code deals with the inserts, but this will help a lot in that discussion. Maybe it's possible to do all the parent inserts first.

Regards
Thomas

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