MariaDB SELECT query keeps stuck in one system but not in another

This is the reduced query showing problem: SELECT t.* FROM transactions t LEFT JOIN assignments a ON a.transaction_id = t.id LEFT JOIN users u2 ON u2.id = a.user_id WHERE ( u2.operational_type IS NULL ); In Production Server (Ubuntu 21.04; mariadb Ver 15.1 Distrib 10.5.13-MariaDB) is executing in 0.0179 seconds. Explain in production server returns: +------+-------------+-------+--------+----------------+----------------+---------+------------------+-------+-------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +------+-------------+-------+--------+----------------+----------------+---------+------------------+-------+-------------------------+ | 1 | SIMPLE | t | ALL | NULL | NULL | NULL | NULL | 56542 | | | 1 | SIMPLE | a | ref | transaction_id | transaction_id | 4 | dbname.t.id | 1 | | | 1 | SIMPLE | u2 | eq_ref | PRIMARY | PRIMARY | 4 | dbname.a.user_id | 1 | Using where; Not exists | +------+-------------+-------+--------+----------------+----------------+---------+------------------+-------+-------------------------+ However in developing server (Ubuntu 22.04.1 LTS; mariadb Ver 15.1 Distrib 10.6.7-MariaDB) it gets stuck, In processlist it's state is sending data, it has been more than 30 minutes. Its EXPLAIN is as following: +------+-------------+-------+--------+----------------+---------+---------+------------------+-------+-------------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +------+-------------+-------+--------+----------------+---------+---------+------------------+-------+-------------------------------------------------+ | 1 | SIMPLE | t | ALL | NULL | NULL | NULL | NULL | 48735 | | | 1 | SIMPLE | a | ALL | transaction_id | NULL | NULL | NULL | 1 | Using where; Using join buffer (flat, BNL join) | | 1 | SIMPLE | u2 | eq_ref | PRIMARY | PRIMARY | 4 | dbname.a.user_id | 1 | Using where; Not exists | +------+-------------+-------+--------+----------------+---------+---------+------------------+-------+-------------------------------------------------+ What is the cause? How to troubleshoot? EDIT: SHOW TABLE STATUS for Production Server. +-----------------------+--------+---------+------------+-------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+------------------+-----------+ | Name | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time | Update_time | Check_time | Collation | Checksum | Create_options | Comment | Max_index_length | Temporary | +-----------------------+--------+---------+------------+-------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+------------------+-----------+ | assignments | InnoDB | 10 | Dynamic | 50175 | 52 | 2637824 | 0 | 3178496 | 4194304 | 51273 | 2022-07-08 08:18:28 | 2022-08-29 12:40:28 | NULL | utf8mb4_spanish_ci | NULL | | | 0 | N | | transactions | InnoDB | 10 | Dynamic | 37315 | 1505 | 56180736 | 0 | 3719168 | 7340032 | 41549 | 2022-07-13 11:18:23 | 2022-09-03 15:34:44 | NULL | utf8mb4_spanish_ci | NULL | | | 0 | N | | users | InnoDB | 10 | Dynamic | 243 | 741 | 180224 | 0 | 81920 | 0 | 267 | 2022-08-20 12:33:16 | 2022-09-08 11:12:24 | NULL | utf8mb4_spanish_ci | NULL | | | 0 | N SHOW TABLE STATUS developing server: +-----------------------+--------+---------+------------+-------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+--------------------+----------+----------------+---------+------------------+-----------+ | Name | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time | Update_time | Check_time | Collation | Checksum | Create_options | Comment | Max_index_length | Temporary | | assignments | InnoDB | 10 | Dynamic | 0 | 0 | 16384 | 0 | 32768 | 4194304 | 75369 | 2022-09-11 08:05:19 | NULL | NULL | utf8mb4_spanish_ci | NULL | | | 0 | N | | transactions | InnoDB | 10 | Dynamic | 48735 | 1497 | 72974336 | 0 | 4767744 | 6291456 | 62236 | 2022-09-11 08:05:15 | NULL | NULL | utf8mb4_spanish_ci | NULL | | | 0 | N | | users | InnoDB | 10 | Dynamic | 275 | 714 | 196608 | 0 | 98304 | 0 | 296 | 2022-09-11 12:09:11 | NULL | NULL | utf8mb4_spanish_ci | NULL | | | 0 | N | I don't understand why assigments table show 0 rows. SELECT COUNT(*) FROM assignments WHERE 1 returns 74061