PLSQL Developer hangs waiting for itself

[Worker]

Maybe this is PLSQL Developer's fault, maybe it's Oracle's fault, or maybe I'm doing something really stupid, but I can make PLSQL Developer hang by doing the following:

In a command window, run the following:

-- Create table
create table DEADLOCK_PARENT
(
  parent_id number
);
-- Create/Recreate primary, unique and foreign key constraints
alter table DEADLOCK_PARENT
  add constraint PK_DEADLOCK_PARENT primary key (PARENT_ID);

-- Create table
create table DEADLOCK_CHILD
(
  child_id  number,
  parent_id number
);
-- Create/Recreate primary, unique and foreign key constraints
alter table DEADLOCK_CHILD
  add constraint PK_DEADLOCK_CHILD primary key (CHILD_ID);
alter table DEADLOCK_CHILD
  add constraint FK_DEADLOCK_CHILD foreign key (PARENT_ID)
  references deadlock_parent (PARENT_ID) on delete cascade;

insert into deadlock_parent values (1);
insert into deadlock_child values (1, 1);
commit;

Now open a SQL window, and run:

select * from DEADLOCK_CHILD for update;

Now open another SQL window, and run:

select * from DEADLOCK_PARENT for update;

And in that window, click the little lock icon, remove the row from the table and click the green checkmark (note: I have "AutoCommit posted records" checked). PLSQL Developer now hangs.

Looking at the Sessions window, each SQL window has its own session, so it makes sense that the commit can't happen until the "for update" on DEADLOCK_CHILD is released. The problem is that all of PLSQL Developer is unresponsive, so I can't switch to that other SQL window to commit/rollback.

Note: fixing this is not an immediate priority to me. This is not something I do every day

 

[Marco Kalter]

We'll look into this.