InnoDB: Waiting for the background threads to start
InnoDB: Error: tablespace size stored in header is 3712 pages, but
InnoDB: the sum of data file sizes is only 3072 pages
InnoDB: Cannot start InnoDB. The tail of the system tablespace is
InnoDB: missing. Have you edited innodb_data_file_path in my.cnf in an
InnoDB: inappropriate way, removing ibdata files from there?
InnoDB: You can set innodb_force_recovery=1 in my.cnf to force
InnoDB: a startup if you are trying to recover a badly corrupt database.


InnoDB: Assertion failure in thread 3876 in file ha_innodb.cc line 17352
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to http://bugs.mysql.com.
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: http://dev.mysql.com/doc/refman/5.6/en/forcing-innodb-recovery.html
InnoDB: about forcing recovery.


InnoDB: Assertion failure in thread 140154354255616 in file trx0purge.c line 848
InnoDB: Failing assertion: purge_sys->purge_trx_no <= purge_sys->rseg->last_trx_no
InnoDB: We intentionally generate a memory trap.


InnoDB: Your database may be corrupt or you may have copied the InnoDB tablespace but not the InnoDB log files. Please refer to http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html for information about forcing recovery


[ERROR] InnoDB: Attempted to open a previously opened tablespace. Previous tablespace database/table uses space ID: 882 at filepath

[Note] InnoDB: Starting crash recovery.
[ERROR] InnoDB: Tablespace 11904 was not found at ./example_db/example1.ibd.
[ERROR] InnoDB: Set innodb_force_recovery=1 to ignore this and to permanently lose all changes to the tablespace.
[ERROR] InnoDB: Tablespace 11905 was not found at ./example_db/example2.ibd.
[ERROR] InnoDB: Cannot continue operation.


InnoDB: Error: space header page consists of zero bytes in data file ./ibdata1

InnoDB: Database page corruption on disk or a failed file read of page 660. A table cannot be properly queried with the SELECT statement - additional possible output: MariaDB [psa]> select * from db_example.misc;
ERROR 2006 (HY000): MySQL server has gone away No connection. Trying to reconnect...

mysql -uroot -p < employees.sql
Enter password: ********


mysql -uroot -p
Enter password: ********
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 13
Server version: 8.0.14 MySQL Community Server - GPL

Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

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

mysql> use  employees;
Database changed

mysql> select count(*) from employees;
+----------+
| count(*) |
+----------+
|     1000 |
+----------+
1 row in set (0.00 sec)

mysql> drop database employees;
Query OK, 14 rows affected (0.16 sec)

#sync
#sync

mysql> select count(*) from employees.employees;

+----------+
| count(*) |
+----------+
|   300024 |
+----------+
1 row in set (0.09 sec)

mysql> select @@datadir;
+-----------+
| @@datadir |
+-----------+
| /m01/     |
+-----------+
1 row in set (0.00 sec)

mysql> drop table employees.employees;
ERROR 1217 (23000): Cannot delete or update a parent row: a foreign key constraint fails


mysql> SET FOREIGN_KEY_CHECKS=0;
Query OK, 0 rows affected (0.00 sec)

mysql> drop table employees.employees;
Query OK, 0 rows affected (0.02 sec)

mysql> ^DBye
 
 
#sync
#sync

mysql> use  employees;
Database changed

mysql> select count(*) from employees;
+----------+
| count(*) |
+----------+
|     1000 |
+----------+
1 row in set (0.00 sec)


mysql> delete from employees;


mysql> flush table employees with read lock;
Query OK, 0 rows affected (0.01 sec)

mysql> show create table employees;
+-----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table     | Create Table                                                                                                                                                                                                                                                                                                                                  |
+-----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| employees | CREATE TABLE `employees` (
  `emp_no` int(11) NOT NULL,
  `birth_date` date NOT NULL,
  `first_name` varchar(14) NOT NULL,
  `last_name` varchar(16) NOT NULL,
  `gender` enum('M','F') NOT NULL,
  `hire_date` date NOT NULL,
  PRIMARY KEY (`emp_no`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci ROW_FORMAT=DYNAMIC |
+-----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)