instead of triggers refreshing materialized views - Mailing list pgsql-general

Hi There,

This is with postgresql 9.5.

For a combination of compatibility/speed issues, I have an updatable view
that selects from a bunch of tables, views and a materialized view.

I would really like updates to the base table (or the updatabale view) to
somehow trigger a refresh of the materialized view.  When I do this via
trigger, I get something like:

psql:mvtest.sql:30: ERROR:  cannot REFRESH MATERIALIZED VIEW "bar" because it is being used by active queries in this
session

I get what's happening but I am wondering if there is some way I can
accomplish what I'm after without either going to a pgnotify-like solution
with external maintenance of the view or just abandoning the materialized
view and having a table that acts like a materialized view.

The below code is a greatly simplified version of what I am trying to do that
illustrates the issue.

help?

thanks,
-Todd

---<snip>---
create table foo ( id serial, primary key (id), thing text );

create function upd_foo() returns trigger as $$
begin
    refresh materialized view bar;
END; $$ LANGUAGE plpgsql SECURITY DEFINER;

CREATE TRIGGER trigger_upd_foo
AFTER UPDATE ON foo
EXECUTE PROCEDURE upd_foo();

create materialized view bar AS select * from foo;

create view baz AS select * from bar;

create function upd_baz() returns trigger AS $$
BEGIN
    UPDATE foo set thing = NEW.thing, id = NEW.id WHERE id = OLD.id;
END; $$ LANGUAGE plpgsql SECURITY DEFINER;

CREATE TRIGGER trigger_upd_baz
INSTEAD OF UPDATE ON baz FOR EACH ROW EXECUTE PROCEDURE upd_baz();

insert into foo (id, thing) values (1, 'test');

refresh materialized view bar;

update baz set thing = 'test2' where id = 1;