In 1.2, we had

        if (csep->limitNum() != (uint64_t) - 1 &&

                gwi.subQuery && !gwi.correlatedTbNameVec.empty())

In 1.4, we have

        if (gwi.subQuery && !gwi.correlatedTbNameVec.empty() && csep->hasOrderBy())

This was changed in MCOL-2178 'Fix for handlers fallback mechanism patch'
However, csep->hasOrderBy() is never set for subquery, so the error is never detected.

I commented out the error detection code in 1.2 and the query succeeded, so it appears the system has supported at least this one example of a limit in a subquery for a while.

Does it really returns expected results?

The result set returned is incorrect. We must re-enable the error message.

I had submitted, as part of MCOL-3594, changes to support the new behavior. Since the new behavior is incorrect and has been reverted, I also reverted the changes in the Pull Request for MCOL-3594

DDL and DML for example:

CREATE TABLE t1 (lid int, name char(10)) engine=columnstore;
INSERT INTO t1 (lid, name) VALUES (1, 'YES'), (2, 'NO');

CREATE TABLE t2 ( id int, gid int, lid int, dt date) engine=columnstore;
INSERT INTO t2 (id, gid, lid, dt) VALUES
(1, 1, 1, '2007-01-01'),(2, 1, 2, '2007-01-02'),
(3, 2, 2, '2007-02-01'),(4, 2, 1, '2007-02-02');

Build verified: 1.4.4-1, Jenkins-20200506

The fix is to restore the error checking and return a messages for non-support syntax

Server version: 10.4.12-6-MariaDB-enterprise MariaDB Enterprise Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [mytest]> CREATE TABLE t1 (lid int, name char(10)) engine=columnstore;
Query OK, 0 rows affected (0.219 sec)

MariaDB [mytest]> INSERT INTO t1 (lid, name) VALUES (1, 'YES'), (2, 'NO');
Query OK, 2 rows affected (1.334 sec)
Records: 2 Duplicates: 0 Warnings: 0

MariaDB [mytest]> CREATE TABLE t2 ( id int, gid int, lid int, dt date) engine=columnstore;
Query OK, 0 rows affected (0.181 sec)

MariaDB [mytest]> INSERT INTO t2 (id, gid, lid, dt) VALUES
-> (1, 1, 1, '2007-01-01'),(2, 1, 2, '2007-01-02'),
-> (3, 2, 2, '2007-02-01'),(4, 2, 1, '2007-02-02');
Query OK, 4 rows affected (0.456 sec)
Records: 4 Duplicates: 0 Warnings: 0

MariaDB [mytest]> SELECT DISTINCT t2.gid AS lgid,
-> (SELECT t1.name FROM t1, t2
-> WHERE t1.lid = t2.lid AND t2.gid = lgid
-> ORDER BY t2.dt DESC LIMIT 1
-> ) as clid
-> FROM t2;
ERROR 1815 (HY000): Internal error: IDB-3019: Limit within a correlated subquery is currently not supported.
MariaDB [mytest]> CREATE VIEW v1 AS
-> SELECT DISTINCT t2.gid AS lgid,
-> (SELECT t1.name FROM t1, t2
-> WHERE t1.lid = t2.lid AND t2.gid = lgid
-> ORDER BY t2.dt DESC LIMIT 1
-> ) as clid
-> FROM t2;
Query OK, 0 rows affected (0.001 sec)

MariaDB [mytest]> SELECT * FROM v1;
ERROR 1815 (HY000): Internal error: IDB-3019: Limit within a correlated subquery is currently not supported.