# Copyright Materialize, Inc. and contributors. All rights reserved.
#
# Use of this software is governed by the Business Source License
# included in the LICENSE file at the root of this repository.
#
# As of the Change Date specified in that file, in accordance with
# the Business Source License, use of this software will be governed
# by the Apache License, Version 2.0.

mode cockroach

simple conn=mz_system,user=mz_system
ALTER SYSTEM SET enable_eager_delta_joins TO true;
----
COMPLETE 0

# Tests for nested WITH MUTUALLY RECURSIVE

statement ok
CREATE TABLE edges (src int, dst int);

statement ok
INSERT INTO edges SELECT x, x + 1 FROM generate_series(0, 9) as x;

statement ok
INSERT INTO edges VALUES (4, 2), (8, 6);

statement ok
CREATE VIEW strongly_connected_components AS
WITH MUTUALLY RECURSIVE
    intra_edges (src int, dst int) as (
        SELECT * FROM edges
        EXCEPT ALL
        SELECT * FROM edges_delayed
        UNION ALL
        SELECT src, dst
        FROM
            edges,
            forward_labels f_src,
            forward_labels f_dst,
            reverse_labels r_src,
            reverse_labels r_dst
        WHERE src = f_src.node
            AND src = r_src.node
            AND dst = f_dst.node
            AND dst = r_dst.node
            AND f_src.label = f_dst.label
            AND r_src.label = r_dst.label
    ),
    forward_labels (node int, label int) AS (
        WITH MUTUALLY RECURSIVE
            label (node int, comp int) AS (
                SELECT dst, MIN(comp)
                FROM (
                    SELECT dst, dst AS comp FROM edges
                    UNION ALL
                    SELECT intra_edges.dst, label.comp
                    FROM intra_edges, label
                    WHERE intra_edges.src = label.node
                )
                GROUP BY dst
            )
        SELECT * FROM label
    ),
    reverse_labels (node int, label int) AS (
        WITH MUTUALLY RECURSIVE
            label (node int, comp int) AS (
                SELECT src, MIN(comp)
                FROM (
                    SELECT src, src AS comp FROM edges
                    UNION ALL
                    SELECT intra_edges.src, label.comp
                    FROM intra_edges, label
                    WHERE intra_edges.dst = label.node
                )
                GROUP BY src
            )
        SELECT * FROM label
    ),
    edges_delayed (src int, dst int) AS (SELECT * FROM edges)
SELECT * FROM forward_labels UNION SELECT * FROM reverse_labels;

statement ok
CREATE DEFAULT INDEX ON strongly_connected_components;

query II
SELECT size, COUNT(*) FROM (
    SELECT label, COUNT(*) as size
    FROM strongly_connected_components
    GROUP BY label
)
GROUP BY size;
----
1  5
3  2