Mamp won't start mysql server (mac)

Question

I had mamp up and running (wordpress) and was having no issues. Then suddenly the server went down, and hasn't started again. Their are some other threads about this topic, but I haven't been able to get it figured out. I have confirmed that there are no mysql processes going.... this is my mysql_error_log :

161201 01:04:22 mysqld_safe Starting mysqld daemon with databases from /Applications/MAMP/db/mysql56
2016-12-01 01:04:23 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2016-12-01 01:04:23 0 [Note] /Applications/MAMP/Library/bin/mysqld (mysqld 5.6.33) starting as process 49478 ...
2016-12-01 01:04:23 49478 [Warning] Setting lower_case_table_names=2 because file system for /Applications/MAMP/db/mysql56/ is case insensitive
2016-12-01 01:04:23 49478 [Note] Plugin 'FEDERATED' is disabled.
2016-12-01 01:04:23 49478 [Note] InnoDB: Using atomics to ref count buffer pool pages
2016-12-01 01:04:23 49478 [Note] InnoDB: The InnoDB memory heap is disabled
2016-12-01 01:04:23 49478 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-12-01 01:04:23 49478 [Note] InnoDB: Memory barrier is not used
2016-12-01 01:04:23 49478 [Note] InnoDB: Compressed tables use zlib 1.2.8
2016-12-01 01:04:23 49478 [Note] InnoDB: Using CPU crc32 instructions
2016-12-01 01:04:23 49478 [Note] InnoDB: Initializing buffer pool, size = 128.0M
2016-12-01 01:04:23 49478 [Note] InnoDB: Completed initialization of buffer pool
2016-12-01 01:04:23 49478 [Note] InnoDB: Highest supported file format is Barracuda.
2016-12-01 01:04:23 49478 [Note] InnoDB: The log sequence numbers 0 and 0 in ibdata files do not match the log sequence number 9969064 in the ib_logfiles!
2016-12-01 01:04:23 49478 [Note] InnoDB: Database was not shutdown normally!
2016-12-01 01:04:23 49478 [Note] InnoDB: Starting crash recovery.
2016-12-01 01:04:23 49478 [Note] InnoDB: Reading tablespace information from the .ibd files...
2016-12-01 01:04:23 49478 [ERROR] InnoDB: Attempted to open a previously opened tablespace. Previous tablespace mysql/slave_worker_info uses space ID: 5 at filepath: ./mysql/slave_worker_info.ibd. Cannot open tablespace wordpress/wp_term_taxonomy which uses space ID: 5 at filepath: ./wordpress/wp_term_taxonomy.ibd
2016-12-01 01:04:23 7fffc52a43c0  InnoDB: Operating system error number 2 in a file operation.
InnoDB: The error means the system cannot find the path specified.
InnoDB: If you are installing InnoDB, remember that you must create
InnoDB: directories yourself, InnoDB does not create them.
InnoDB: Error: could not open single-table tablespace file ./wordpress/wp_term_taxonomy.ibd
InnoDB: We do not continue the crash recovery, because the table may become
InnoDB: corrupt if we cannot apply the log records in the InnoDB log to it.
InnoDB: To fix the problem and start mysqld:
InnoDB: 1) If there is a permission problem in the file and mysqld cannot
InnoDB: open the file, you should modify the permissions.
InnoDB: 2) If the table is not needed, or you can restore it from a backup,
InnoDB: then you can remove the .ibd file, and InnoDB will do a normal
InnoDB: crash recovery and ignore that table.
InnoDB: 3) If the file system or the disk is broken, and you cannot remove
InnoDB: the .ibd file, you can set innodb_force_recovery > 0 in my.cnf
InnoDB: and force InnoDB to continue crash recovery here.
161201 01:04:23 mysqld_safe mysqld from pid file /Applications/MAMP/tmp/mysql/mysql.pid ended

Answer 1

It means one of your tables is corrupted. Weirdly this has happened to frequently upon a machine crash. This is how I fixed it:

1. open my.cnf (in MAMP > File > Edit Template > MySQL)
2. add the line: innodb_force_recovery = 1
3. save and start servers

The table will likely still be broken, but mysql should start. It means you may have to replace your table: wp_term_taxonomy

Note: If innodb_force_recovery = 1 does not work, try going up in numbers: innodb_force_recovery = 2 (etc) But tread carefully. Here's MySQL's warning on this setting: https://dev.mysql.com/doc/refman/5.5/en/forcing-innodb-recovery.html

Answer 2

All your MAMP databases are stored in separate folders at /Library/Application Support/appsolute/MAMP PRO/db/mysql56/. According to your error log there's a problem with ./wordpress/wp_term_taxonomy.ib – that is, the table term_taxonomy in the database wordpress. One way to solve this is to simply delete all traces of that database – I hope you have a copy from before it got corrupted to restore it from. This is how you delete it:

1. Quit the MAMP server.

2. Delete the database folder and its contents – in your case the database name is wordpress:

   $ rm -r /Library/Application\ Support/appsolute/MAMP\ PRO/db/mysql56/wordpress
   

3. Delete the three InnoDB files ib_logfile0, ib_logfile1, and ibdata1. Fear not; fresh copies will be created next time you start MySQL from within MAMP.

   $ rm /Library/Application\ Support/appsolute/MAMP\ PRO/db/mysql56/ib_logfile0
   $ rm /Library/Application\ Support/appsolute/MAMP\ PRO/db/mysql56/ib_logfile1
   $ rm /Library/Application\ Support/appsolute/MAMP\ PRO/db/mysql56/ibdata1
   

4. Start the MAMP server.