Test case for https://github.com/citusdata/cstore_fdw/issues/132

testcase-cstore-segfault.sql

create table queue
(
    id integer,
    diff integer
);

create table cache
(
    id integer primary key,
    count integer not null,
    last_update_at timestamptz
);

create or replace function process_queue()
returns bool language plpgsql
as $body$
begin

    insert into cache (id, count, last_update_at)
        select id, sum(diff), now()
        from queue
        group by id
    on conflict (id) do update set
        count = cache.count + EXCLUDED.count,
        last_update_at = EXCLUDED.last_update_at
        ;

     -- removing the truncate line resolves the issue
     truncate queue;

    return true;
end;
$body$;

-- Need to invoke the following a number of times to trigger the segfault in cstore_fdw.so
-- No data is required
select process_queue();
select process_queue();
select process_queue();
select process_queue();
select process_queue();