PolarDB crashes (Docker container exits) when executing a complex SQL query with nested JOINs, LATERAL subqueries, and EXIST

Description:
When executing a highly complex SQL query involving multiple nested JOINs, LATERAL subqueries, and EXISTS conditions, the PolarDB server running inside a Docker container report:

ERROR 2013 (HY000): Lost connection to MySQL server during query

The server must be reconnect to recover.

How to repeat:

-- Schema
CREATE TABLE users (
    id           INT,
    username     VARCHAR(100),
    email        VARCHAR(255),
    age          INT,
    status       VARCHAR(20),
    created_at   TIMESTAMP NULL,
    score        DOUBLE
);

CREATE TABLE posts (
    id          INT,
    user_id     INT,
    title       VARCHAR(255),
    content     VARCHAR(1000),
    views       INT,
    likes       INT,
    created_at  TIMESTAMP NULL,
    rating      DOUBLE
);

CREATE TABLE comments (
    id          INT,
    post_id     INT,
    user_id     INT,
    content     VARCHAR(1000),
    is_spam     INT,
    created_at  TIMESTAMP NULL
);

CREATE TABLE orders (
    id          INT,
    user_id     INT,
    amount      DOUBLE,
    status      VARCHAR(20),
    created_at  TIMESTAMP NULL
);

INSERT INTO users VALUES
(1, 'alice', 'alice@test.com', 20, 'active',  '2022-01-01 10:00:00', 88.5),
(2, 'bob',   'bob@test.com',   30, 'active',  '2022-01-02 11:00:00', 92.3),
(3, 'carol', NULL,             NULL, 'banned','2022-01-03 12:00:00', NULL),
(4, 'dave',  'dave@test.com',  45, 'active',  '2022-01-04 13:00:00', 65.2),
(5, NULL,    'null@test.com',  18, 'inactive','2022-01-05 14:00:00', 70.0);

INSERT INTO posts VALUES
(1, 1, 'Hello World', 'First post', 100, 10, '2022-01-10 10:00:00', 4.5),
(2, 1, 'Another Post', NULL,        150, 20, '2022-01-11 11:00:00', 3.0),
(3, 2, 'Bob Post',     'Content',   NULL,  5, '2022-01-12 12:00:00', NULL),
(4, 3, NULL,           'Empty',     50,   2, '2022-01-13 13:00:00', 5.0),
(5, 4, 'Last Post',    'Last',      300,  30,'2022-01-14 14:00:00', 4.9);

INSERT INTO comments VALUES
(1, 1, 2, 'Nice post', 0, '2022-01-20 10:00:00'),
(2, 1, 3, 'Spam here', 1,  '2022-01-21 11:00:00'),
(3, 2, 1, 'Thanks',    0, '2022-01-22 12:00:00'),
(4, 4, 5, NULL,        0, '2022-01-23 13:00:00');

INSERT INTO orders VALUES
(1, 1, 100.00, 'paid',    '2022-02-01 09:00:00'),
(2, 1, 200.50, 'shipped', '2022-02-02 10:00:00'),
(3, 2, NULL,   'failed',  '2022-02-03 11:00:00'),
(4, 3, 50.00,  'paid',    '2022-02-04 12:00:00'),
(5, 5, 999.99, 'paid',    '2022-02-05 13:00:00');

-- Trigger SQL
SELECT 1
FROM (
    SELECT ref_0.age AS c0, ref_0.id AS c1, ref_0.id AS c2, ref_0.email AS c3
    FROM users ref_0
    WHERE ref_0.created_at IS NOT NULL AND false
    LIMIT 192
) subq_0
RIGHT JOIN users ref_1
LEFT JOIN comments ref_2
    LEFT JOIN posts ref_3
        INNER JOIN comments ref_4 ON true
        RIGHT JOIN posts ref_11
            RIGHT JOIN comments ref_12 ON true
        ON ref_3.views = ref_12.id
    ON false
    INNER JOIN (
        SELECT ref_13.created_at AS c0,
               (SELECT content FROM comments LIMIT 1 OFFSET 80) AS c1,
               (SELECT amount FROM orders LIMIT 1 OFFSET 5) AS c3
        FROM orders ref_13
        WHERE true
    ) subq_1 ON true
ON true
ON EXISTS (
    SELECT 1
    FROM comments ref_18
    LEFT JOIN comments ref_19
        ON (false OR ref_11.likes IS NULL OR subq_1.c1 IS NOT NULL)
    WHERE EXISTS (
        SELECT 1
        FROM posts ref_20
        WHERE ref_2.content IS NULL
        LIMIT 90
    )
),
LATERAL (
    SELECT ref_12.content AS c0
    FROM (
        SELECT ref_2.user_id AS c5
        FROM users ref_21
        INNER JOIN orders ref_22
            ON (63 IS NOT NULL OR (SELECT amount FROM orders LIMIT 1 OFFSET 4) IS NOT NULL)
        WHERE ref_21.username IS NOT NULL
    ) subq_3
    WHERE ref_1.username IS NOT NULL
    LIMIT 25
) subq_4,
LATERAL (
    SELECT 6 AS c6
    FROM users ref_25
    INNER JOIN orders ref_26
        INNER JOIN posts ref_27
            LEFT JOIN orders ref_28 ON true
            LEFT JOIN posts ref_31 ON true
        ON ref_31.content IS NULL
    ON ref_25.id = ref_27.id
    WHERE (
        true AND (
            false AND (true AND false AND ref_28.created_at IS NOT NULL)
            AND subq_1.c3 IS NOT NULL
            AND ref_4.content IS NOT NULL
            AND false
            OR true
        )
        OR EXISTS (
            SELECT 1
            FROM users ref_46
            WHERE ref_31.views IS NULL
            LIMIT 55
        )
        OR (
            (subq_0.c0 IS NOT NULL OR ref_3.title IS NULL)
            AND ref_3.title IS NULL
        )
        OR EXISTS (
            SELECT 1
            FROM orders ref_47
            RIGHT JOIN users ref_48 ON true
            WHERE true
               OR EXISTS (
                    SELECT 1
                    FROM posts ref_49,
                         LATERAL (
                             SELECT 1
                             FROM comments ref_50
                             WHERE ref_1.username IS NULL
                         ) subq_11
                    WHERE true
                )
            LIMIT 75
        )
        OR EXISTS (
            SELECT ref_25.id
            FROM comments ref_53
            WHERE true
              AND ref_1.status IS NULL
              AND true
            LIMIT 59
        )
        OR EXISTS (
            SELECT 1
            FROM comments ref_56
            WHERE EXISTS (
                SELECT 1
                FROM posts ref_57
                WHERE ref_27.created_at IS NOT NULL
                LIMIT 53
            )
            AND ref_28.created_at IS NOT NULL
            LIMIT 112
        )
    )
    LIMIT 142
) subq_12
WHERE EXISTS (
    SELECT 1
    FROM users ref_99,
         LATERAL (
             SELECT ref_12.id AS c0, ref_99.age AS c1, subq_12.c6 AS c2, ref_99.username AS c3
             FROM users ref_100
             WHERE subq_0.c3 IS NULL
             LIMIT 71
         ) subq_26
    WHERE EXISTS (
        SELECT 1
        FROM users ref_101
        LEFT JOIN orders ref_102 ON true
        WHERE EXISTS (
            SELECT 1
            FROM users ref_103
            WHERE ref_1.score IS NULL
            LIMIT 38
        )
        LIMIT 110
    )
    LIMIT 11
)
LIMIT 176;

version info:

MySQL [test]> select version();
+----------------------------------+
| version()                        |
+----------------------------------+
| 8.0.32-X-Cluster-8.4.19-20250825 |
+----------------------------------+
1 row in set (0.00 sec)

MySQL [test]> select polardb_version();
+----------------------------------------------------------+
| polardb_version()                                        |
+----------------------------------------------------------+
| PolarDB V2.0_2.4.2_8.4.19-20250825 (Distributed Edition) |
+----------------------------------------------------------+
1 row in set (0.00 sec)

No source files or tests are named. Start by running the supplied schema and query in a Docker PolarDB instance matching the listed MySQL and PolarDB versions, then inspect server logs and the connection state; done means the query no longer crashes the server or drops the client connection.