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I have a big problem with a MySQL database stored on my raspberry (InnoDB engine). I'm not very expert in this field but I'll try to explain to you the problem.

MySQL crash everytime that I try to start it and I need to recover the data stored inside the DB. The error is:

error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'

I just tried to start MySQL with the innodb_force_recovery flag from 1 to 6 but it still crashing. From the log I understood that the problem is a corruption inside some tables.

I tried to check my database file with https://recovery.twindb.com/ and it shows that some tables inside "mysql" database need to be recovered and the tables inside "production" database (the mine) are ok, indeed I can see all my data on this website. How can easly recover my data? There is some free tools or script that I can use? I have all files as ibdata01, *.frm, *.ibd

UPDATE #1:

/etc/mysql/my.cnf

    #

# The MySQL database server configuration file.

#

# You can copy this to one of:

# - "/etc/mysql/my.cnf" to set global options,

# - "~/.my.cnf" to set user-specific options.

# 

# One can use all long options that the program supports.

# Run program with --help to get a list of available options and with

# --print-defaults to see which it would actually understand and use.

#

# For explanations see

# http://dev.mysql.com/doc/mysql/en/server-system-variables.html



#

# * IMPORTANT: Additional settings that can override those from this file!

#   The files must end with '.cnf', otherwise they'll be ignored.

#



!includedir /etc/mysql/conf.d/

!includedir /etc/mysql/mysql.conf.d/

/etc/mysql/mysql.conf.d/mysqld.cnf

#

# The MySQL database server configuration file.

#

# You can copy this to one of:

# - "/etc/mysql/my.cnf" to set global options,

# - "~/.my.cnf" to set user-specific options.

# 

# One can use all long options that the program supports.

# Run program with --help to get a list of available options and with

# --print-defaults to see which it would actually understand and use.

#

# For explanations see

# http://dev.mysql.com/doc/mysql/en/server-system-variables.html



# This will be passed to all mysql clients

# It has been reported that passwords should be enclosed with ticks/quotes

# escpecially if they contain "#" chars...

# Remember to edit /etc/mysql/debian.cnf when changing the socket location.



# Here is entries for some specific programs

# The following values assume you have at least 32M ram



[mysqld_safe]

socket      = /var/run/mysqld/mysqld.sock

nice        = 0



[mysqld]

#

# * Basic Settings

#

user        = mysql

pid-file    = /var/run/mysqld/mysqld.pid

socket      = /var/run/mysqld/mysqld.sock

port        = 3306

basedir     = /usr

datadir     = /var/lib/mysql

tmpdir      = /tmp

lc-messages-dir = /usr/share/mysql

skip-external-locking

#

# Instead of skip-networking the default is now to listen only on

# localhost which is more compatible and is not less secure.

bind-address        = 127.0.0.1

#

# * Fine Tuning

#

key_buffer_size     = 16M

max_allowed_packet  = 16M

thread_stack        = 192K

thread_cache_size       = 8

# This replaces the startup script and checks MyISAM tables if needed

# the first time they are touched

myisam-recover-options  = BACKUP

#max_connections        = 100

#table_open_cache       = 64

#thread_concurrency     = 10

#

# * Query Cache Configuration

#

query_cache_limit   = 1M

query_cache_size        = 16M

#

# * Logging and Replication

#

# Both location gets rotated by the cronjob.

# Be aware that this log type is a performance killer.

# As of 5.1 you can enable the log at runtime!

#general_log_file        = /var/log/mysql/mysql.log

#general_log             = 1

#

# Error log - should be very few entries.

#

log_error = /var/log/mysql/error.log

#

# Here you can see queries with especially long duration

#slow_query_log     = 1

#slow_query_log_file    = /var/log/mysql/mysql-slow.log

#long_query_time = 2

#log-queries-not-using-indexes

#

# The following can be used as easy to replay backup logs or for replication.

# note: if you are setting up a replication slave, see README.Debian about

#       other settings you may need to change.

#server-id      = 1

#log_bin            = /var/log/mysql/mysql-bin.log

expire_logs_days    = 10

max_binlog_size   = 100M

#binlog_do_db       = include_database_name

#binlog_ignore_db   = include_database_name

#

# * InnoDB

#

# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.

# Read the manual for more InnoDB related options. There are many!

#

# * Security Features

#

# Read the manual, too, if you want chroot!

# chroot = /var/lib/mysql/

#

# For generating SSL certificates I recommend the OpenSSL GUI "tinyca".

#

# ssl-ca=/etc/mysql/cacert.pem

# ssl-cert=/etc/mysql/server-cert.pem

# ssl-key=/etc/mysql/server-key.pem

If I try to start mysql without innodb_force_recovery flag this is the result:

pc@pc-hp:/$ sudo service mysql start

Job for mysql.service failed because the control process exited with error code.

See "systemctl status mysql.service" and "journalctl -xe" for details.

And this is error.log:
https://pastebin.com/eeSuMxBT

You can use Undrop for InnoDB a tool behind recovery.twindb.com.
To recover corrupt database you need to follow steps from https://twindb.com/recover-corrupt-mysql-database/

Parse the ibd file:

# ./stream_parser -f /var/lib/mysql/sakila/actor.ibd

The dump records from the PRIMARY index:

# ./c_parser -6f pages-actor.ibd/FIL_PAGE_INDEX/0000000000000015.page 

    -t sakila/actor.sql 

    > dumps/default/actor 2>&1 dumps/default/actor_load.sql

Then load the dump:

# mysql --local-infile sakila < dumps/default/actor_load.sql

SOLUTION 1 (if *.ibd files are good):

• Backup /var/lib/MySQL folder with all data


• 
  

  Remove /var/lib/MySQL and initialize the data folder with mysql_install_db command to not miss the *.cnf file

  
  
  

  OR
  Fresh install mysql

  
  


• Create new database as that one to restore


• Create all tables with the correct schemas (you can recover they with the *.frm files of every table, online there is some tools)


• Remove all tablespace inside mysql with ALTER TABLE "tableName" DISCARD TABLESPACE; (you can do it for every table with a simple bash script)


• Copy all backed-up *.idb files to /var/lib/mysql/yourdb folder



• You may have to set the correct permission to files with sudo chown -R mysql:mysql /var/lib/mysql




• Import all tablespace inside mysql with ALTER TABLE "tableName" IMPORT TABLESPACE;

After this procedure you have all data restored inside your database.

SOLUTION 2 (if *.idb may be corrupted):

• Download undrop-for-innodb and compile it




• execute ./stream_parser -f /var/lib/mysql/ibdata1




• execute for every *.ibd file ./stream_parser -f /var/lib/mysql/yourdatabase/your_ibd.ibd




• create inside YOUR_DB/YOUR_TABLE.sql the CREATE TABLE statement of every table




• execute ./c_parser -6f pages-YOUR_TABLE.ibd/FIL_PAGE_INDEX/FIRST_FILE_OF_FOLDER.page -t YOUR_DB/YOUR_TABLE.sql > dumps/default/YOUR_TABLE 2> dumps/default/YOUR_TABLE_load.sql




• Initialize a new empty database and create all table with the correct schema (you can use YOUR_DB/YOUR_TABLE.sql files)




• Import all data with /dumps/default/YOUR_TABLE_load.sql files