-- A unit whose rollup answers a query is not read, so the value one of its elements holds in a column jsonb_to_recordset declares and the query
-- does not read (a string where the column is a float8) raises no error there, where PostgreSQL's function reads every declared column of the element.
-- A unit that holds such a value is scanned and raises it, as the normal plan does; the units without one keep answering from their rollups.
CREATE EXTENSION pg_sift;
SET client_min_messages = warning;
SET max_parallel_workers_per_gather = 0;
SET cpu_tuple_cost = 0.5;
CREATE TABLE pr_clean (id int, items jsonb) WITH (autovacuum_enabled = off);
INSERT INTO pr_clean
SELECT i, jsonb_build_array(jsonb_build_object('kind', 'k' || i % 5, 'n', i % 9, 'score', (i % 13)::float8 / 4), jsonb_build_object('kind', 'k' || i % 3, 'n', 2, 'score', 1.5))
FROM generate_series(1, 20000) i;
CREATE TABLE pr_dirty (LIKE pr_clean) WITH (autovacuum_enabled = off);
INSERT INTO pr_dirty SELECT id, CASE WHEN id = 17777 THEN jsonb_set(items, '{0,score}', '"abc"') ELSE items END FROM pr_clean;
CREATE INDEX pr_clean_col ON pr_clean USING sift_col (id, items) WITH (paths = 'items[]{kind text, n int4, score float8}', write_buffer_limit = 4096);
CREATE INDEX pr_dirty_col ON pr_dirty USING sift_col (id, items) WITH (paths = 'items[]{kind text, n int4, score float8}', write_buffer_limit = 4096);
VACUUM (FREEZE, ANALYZE, DISABLE_PAGE_SKIPPING) pr_clean, pr_dirty;

\ir test/agg_helpers.sql
-- whether a unit was answered from the rollup (NULL: the query fails)
CREATE FUNCTION from_rollup(q text) RETURNS bool LANGUAGE plpgsql AS $$
DECLARE l text; n int := 0;
BEGIN
  PERFORM set_config(s, 'false', true) FROM unnest(ARRAY['enable_seqscan', 'enable_indexscan', 'enable_bitmapscan', 'enable_indexonlyscan']) s;
  FOR l IN EXECUTE 'EXPLAIN (ANALYZE, COSTS OFF, TIMING OFF, SUMMARY OFF, BUFFERS OFF) ' || q LOOP
    n := coalesce(substring(l from '(\d+) from pre-aggregates')::int, n);
  END LOOP;
  RETURN n > 0;
EXCEPTION WHEN OTHERS THEN RETURN NULL;
END $$;
CREATE FUNCTION check_query(name text, q text) RETURNS TABLE (label text, same bool, rollup bool) LANGUAGE sql AS $$
  SELECT name, outcome(q, false) = outcome(q, true), from_rollup(q)
$$;

SELECT * FROM check_query('clean: kind', $q$
 SELECT e.kind, count(*) FROM pr_clean d CROSS JOIN LATERAL jsonb_to_recordset(d.items) e(kind text, n int, score float8) GROUP BY 1
$q$);
SELECT * FROM check_query('dirty: kind', $q$
 SELECT e.kind, count(*) FROM pr_dirty d CROSS JOIN LATERAL jsonb_to_recordset(d.items) e(kind text, n int, score float8) GROUP BY 1
$q$);
SELECT * FROM check_query('dirty: kind and n', $q$
 SELECT e.kind, count(*), sum(e.n) FROM pr_dirty d CROSS JOIN LATERAL jsonb_to_recordset(d.items) e(kind text, n int, score float8) GROUP BY 1
$q$);

DROP FUNCTION check_query(text, text), from_rollup(text), outcome(text, bool), runs_in_scan(text), pushed, runq;
DROP TABLE pr_clean, pr_dirty;
DROP EXTENSION pg_sift;