Why does my process hang?

Why oh why oh why oh why oh why oh why oh why oh why does my process freeze?

(I'm using Oracle 7.3.3)

Create a parent and child table:

create table parent_tab (

    pfield varchar(20)

        primary key);

create table child_tab (

    pfield varchar(20)
      referencing parent_tab);

Start up two session of SQL-Plus:

1. In session #1 execute:

  insert into parent_tab values ('a');

2) In session #2 execute:

  insert into parent_tab values ('b');
  insert into child_tab values ('b');

3) In session #1 execute:

  delete from parent_tab where pfield = 'a';

Session #1 freezes until session #2 either commits or rolls back.

   AAAAAAAAAAAAAAAAAAAAAAAAAAARRRRRRRRRRRGGGGGGGGGGGGGGGGHHHHHHH!

Session #1 and #2 aren't contending over the same data, they appear to be 'merely' contending over the foreign key relationship. Apparently session #1 is unable to verify that it isn't severing any ties to child_tab while session #2 has an uncommitted transaction pending with child_tab.

Isn't this a major hit against the principle of data concurrency support? Am I missing something basic? Is this a bug? (Naaah, couldn't be, it seems to basic.) What is going on?

  Francis

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