MySQL crash on startup

Question

I'm developing on my laptop with wamp and mysql is running fine from weeks. Today after 60 seconds after boot mysql crashes I and find the following error inside the log:

2016-03-17T20:34:37.662021Z 0 [ERROR] InnoDB: Cannot allocate 4294956804 bytes of memory after 60 retries over 60 seconds. OS error: Not enough space (12). Check if you should increase the swap file or ulimits of your operating system. Note that on most 32-bit computers the process memory space is limited to 2 GB or 4 GB.
2016-03-17 21:34:37 0x2b74  InnoDB: Assertion failure in thread 11124 in file ut0ut.cc line 938
InnoDB: Failing assertion: !m_fatal
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/5.7/en/forcing-innodb-recovery.html
InnoDB: about forcing recovery.
20:34:37 UTC - mysqld got exception 0x80000003 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
Attempting to collect some information that could help diagnose the problem.
As this is a crash and something is definitely wrong, the information
collection process might fail.

key_buffer_size=67108864
read_buffer_size=2097152
max_used_connections=0
max_threads=151
thread_count=0
connection_count=0
It is possible that mysqld could use up to 
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 685380 K  bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x103288c0
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
2016-03-17T20:34:37.682021Z 0 [ERROR] InnoDB: Cannot allocate 4294954524 bytes of memory after 60 retries over 60 seconds. OS error: Not enough space (12). Check if you should increase the swap file or ulimits of your operating system. Note that on most 32-bit computers the process memory space is limited to 2 GB or 4 GB.
2016-03-17 21:34:37 0x2b58  InnoDB: Assertion failure in thread 11096 in file ut0ut.cc line 938
InnoDB: Failing assertion: !m_fatal
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/5.7/en/forcing-innodb-recovery.html
InnoDB: about forcing recovery.

To me it seems that there is a memory issue:

[ERROR] InnoDB: Cannot allocate 4294956804 bytes of memory after 60 retries over 60 seconds. OS error: Not enough space (12).

Could it be that the crash is due to this error? It's weird that mysql try to allocate 4Gb of ram, normally it uses more or less 500Mb.

this is my.ini:

innodb_buffer_pool_size = 16M
# Set .._log_file_size to 25 % of buffer pool size
innodb_log_file_size = 5M
innodb_log_buffer_size = 8M
innodb_flush_log_at_trx_commit = 1
innodb_lock_wait_timeout = 50

I'm running mysql 32 bit on a win7 64bit.

Is this something I can solve changing some variable?

Thanks very much for your help

Solution 1

It was probably a corruption of the InnoDB data. I added

innodb_force_recovery = 2

to my.ini, restarted the DB and I was able to dump all the data and recover it.

Be aware of using this, read the documentation before: http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html

Solution 2

I had similar problem on a CentOS VPS and Stefano Giacone's answer is basically what I did so it worked after hours of researching and a lot of stress...

Well the steps were:

1) Find my.cnf file (mine was located in /etc/my.cnf) and add the line:

innodb_force_recovery = X

replacing X with a integer from 1 to 6, starting from 1 and then incrementing if MySQL won't start. Setting to 4, 5 or 6 can delete your data so be carefull and read http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html before.

2) Restart MySQL service. Only SELECT will run and that's normal at this point.

3) Dump all your databases/schemas with mysqldump one by one, do not compress the dumps because you'd have to uncompress them later anyway in 6).

4) Move (or delete!) only the bd's directories inside /var/lib/mysql, preserving the individual files in the root.

5) Stop MySQL and then uncomment the line added in 1). Start MySQL.

6) Recover all bd's dumped in 3).

That worked for me, good luck!