如何在 postgresql/timescaledb 中以编程方式调用“刷新物化视图”

Question

I have a test suite that runs concurrently. In my testing I have a method called refresh_aggregrates that fundamentally calls REFRESH MATERIALIZED VIEW on my views.

I am having an issue when they happen in parallel i am getting some weird tuples updated concurrently errors.

To fix, I envisioned creating a procedure or a function that would get an advisory_lock , then call the refreshes (so the calls will not interrupt themselves)

Note: I am on pg server 12 (timescale 1.7): (also tested on 11.6, Timescale 1.6)

But when I tried to do this I got: "REFRESH cannot be executed from a function".

^--- Is there a way around this? with sql/plpgsql?

---

My current function...

create or replace procedure refresh_aggregates()
language plpgsql
as $$
    begin
        perform pg_advisory_lock(124);
        execute 'REFRESH MATERIALIZED VIEW daily_events_view';
        execute 'REFRESH MATERIALIZED VIEW weekly_events_view';
        execute 'REFRESH MATERIALIZED VIEW daily_customer_user_events';
        execute 'REFRESH MATERIALIZED VIEW weekly_customer_user_events';
        execute 'REFRESH MATERIALIZED VIEW daily_assessments_view';
        execute 'REFRESH MATERIALIZED VIEW weekly_assessments_view';
        execute 'REFRESH MATERIALIZED VIEW active_user_metrics_by_day';
        execute 'REFRESH MATERIALIZED VIEW wau_mau_weekly_customer_insights';
        perform pg_advisory_unlock(124);
    end;
$$;

call refresh_aggregates();

and results in...

success.public> call refresh_aggregates()
[2020-05-14 15:54:34] [25001] ERROR: REFRESH cannot be executed from a function
[2020-05-14 15:54:34] Where: SQL statement "REFRESH MATERIALIZED VIEW daily_events_view"
[2020-05-14 15:54:34] PL/pgSQL function refresh_aggregates() line 4 at EXECUTE

Answer 1

If you using PostgreSQL 11 or 12, you can use a stored procedure.

For example:

create or replace procedure rmv()
language plpgsql
as
$$
begin
 execute 'refresh materialized view my_mv';
end;
$$;

I have also tested following function:

create or replace function frmv()
returns boolean 
language plpgsql
as
$$
begin
 refresh materialized view mv;
 return true;
end;
$$;

It does not throw any error and works:

select frmv();
 frmv 
------
 t
(1 row)