I stumbled upon this situation when playing with extension upgrades. The problem I was having was that auto-generated datatypes were also being added to the extension and it wasn't obvious this was happening. I know this has been changed in 9.1 stable and in master.
What happened was that I was able to delete the extension in the upgrade script, either by dropping a table with cascade or by outright dropping the extension. It's debatable whether or not that should be allowed, but what happens afterward is what I am more concerned about. In the same upgrade script, after dropping the extension, I created another table and now it is tied to an extension that no longer exists. The output of my psql session is below and the extension files are attached. postgres=# select version(); version --------------------------------------------------------------------------------------------------------------- PostgreSQL 9.1.1 on x86_64-unknown-linux-gnu, compiled by gcc (GCC) 4.6.0 20110603 (Red Hat 4.6.0-10), 64-bit (1 row) postgres=# create database bug_example; CREATE DATABASE postgres=# \c bug_example You are now connected to database "bug_example" as user "postgres". bug_example=# create extension bug_example with version '1.0'; CREATE EXTENSION bug_example=# \d List of relations Schema | Name | Type | Owner --------+----------------+----------+---------- public | table_a | table | postgres public | table_a_id_seq | sequence | postgres (2 rows) bug_example=# alter extension bug_example update to '2.0'; ALTER EXTENSION bug_example=# \d List of relations Schema | Name | Type | Owner --------+----------------+----------+---------- public | table_b | table | postgres public | table_b_id_seq | sequence | postgres (2 rows) bug_example=# drop extension bug_example; ERROR: extension "bug_example" does not exist bug_example=# drop table table_b; ERROR: cache lookup failed for extension 17439 bug_example=# drop table table_b cascade; ERROR: cache lookup failed for extension 17439
bug_example.control
Description: Binary data
create table table_a ( id serial, primary key (id) );
create table table_b ( id serial, primary key (id) );
alter extension bug_example drop table table_a; alter extension bug_example drop sequence table_a_id_seq; drop table table_a cascade; --drop extension bug_example; create table table_b ( id serial, primary key (id) );
-- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs