Istvan Soos <istvan.soos@gmail.com> writes:
> The following minimal reproduction case can be used locally:
> Setup:
> CREATE TABLE a (
> a_id INTEGER PRIMARY KEY NOT NULL,
> a_other_id INTEGER NOT NULL
> );
> CREATE TABLE b (other_id INTEGER PRIMARY KEY NOT NULL);
> BEGIN;
> SELECT * FROM a;
> ALTER TABLE a ADD CONSTRAINT fk_other FOREIGN KEY (a_other_id)
> REFERENCES b(other_id);
> At which point we get '55006: cannot ALTER TABLE "a" because it is
> being used by active queries in this session'. It makes sense,
> however, if we change the SELECT to simple query protocol, the error
> is not present and the transaction completes.
Your message trace isn't too clear (it's not apparent where you're
issuing the ALTER TABLE), but I wonder if you could be failing to
close out the SELECT statement before issuing ALTER. The error
message implies that something is still holding a reference count
on "a"'s relcache entry, and it's hard to see what that could be
except a still-open Portal for the SELECT.
regards, tom lane
