sql/functions/pgq.upgrade_schema.sql
create or replace function pgq.upgrade_schema()
returns int4 as $$
-- updates table structure if necessary
declare
cnt int4 = 0;
begin
-- pgq.subscription.sub_last_tick: NOT NULL -> NULL
perform 1 from information_schema.columns
where table_schema = 'pgq'
and table_name = 'subscription'
and column_name ='sub_last_tick'
and is_nullable = 'NO';
if found then
alter table pgq.subscription
alter column sub_last_tick
drop not null;
cnt := cnt + 1;
end if;
-- create roles
perform 1 from pg_catalog.pg_roles where rolname = 'pgq_reader';
if not found then
create role pgq_reader;
cnt := cnt + 1;
end if;
perform 1 from pg_catalog.pg_roles where rolname = 'pgq_writer';
if not found then
create role pgq_writer;
cnt := cnt + 1;
end if;
perform 1 from pg_catalog.pg_roles where rolname = 'pgq_admin';
if not found then
create role pgq_admin in role pgq_reader, pgq_writer;
cnt := cnt + 1;
end if;
return cnt;
end;
$$ language plpgsql;