Re: Plans for ON DELETE CASCADE? Which index is used, if at all? - Mailing list pgsql-general

Dominique Devienne <ddevienne@gmail.com> writes:
> Hi. Given the classical parent/child schema below, with an ON DELETE
> CASCADE FK constraint, I'd like to know which index is used (if any) to
> delete child rows affected by the CASCADE.

> But explain (analyze) does not give me that.

Yeah, it will just report the time spent in the FK triggers,
not what they were doing exactly.

IIRC, you can see the CASCADE operations with contrib/auto_explain,
if you enable auto_explain.log_nested_statements.

dd=> select * from pg_available_extensions where name like '%auto%';
  name   | default_version | installed_version |                comment
---------+-----------------+-------------------+---------------------------------------
 autoinc | 1.0             |                   | functions for autoincrementing fields
(1 row)

dd=> select * from pg_available_extensions where name like '%explain%';
 name | default_version | installed_version | comment
------+-----------------+-------------------+---------