July 31, 2014

How to recover an orphaned .ibd file with MySQL 5.6

A few years ago Yves Trudeau and Aleksandr Kuzminsky wrote posts about different ways for recovering orphaned .ibd files:

Today I want to show you how to do that in more easy and quick way. In my example I’ll restore a “payment.ibd” file (payment table) from Sakila DB on a server with MySQL 5.5 (but with help from MySQL 5.6 and sandbox).

In my case the OS is CentOS. So I needed to:
install mysqlsandbox(check instructions there)
download latest Percona Server 5.6:

create sandbox

test it

It Works!

check datadir and if the innodb_file_per_table option enabled (this is requirement)

If it’s not enabled then you’ll need to enable it

create empty payment table on 5.6 sandbox

payment_table.sql – is file with “SHOW CREATE TABLE” statement for payment table. The table structure should be the same.

stop sandbox

replace .ibd file (in my case the correct copy of it is located in my homedir)

make sure permissions are ok for .ibd file

start sandbox

Currently if you’ll try to select something from the table you’ll get an error:

select from table

error log

How to Fix it? In 5.6 tablespace management is very improved so the only thing needed is “ALTER TABLE .. DISCARD TABLESPACE” and “ALTER TABLE .. IMPORT TABLESPACE”.

Please check also limitations: Tablespace Copying Limitations

Look at example:

Discard tablespace

Import tablespace

That’s it, data recovered, payment table accessible on 5.6 sandbox.

Now check if data exists in payment table on sandbox:

Exists.

So dump it from sandbox and restore on 5.5:

dump from 5.6

restore to 5.5

Check if data exists on 5.5

During my work with this case I got into a situation in which the drop table payment on 5.5 wasn’t possible because payment.idb there wasn’t correct – so the server crashed each time I tried to access to this table. The workaround is:
- stop server
- rm .ibd file
- start server
- drop table as usually by DROP TABLE command

About Michael Rikmas

Michael joined Percona in October 2007. He serves in several roles, including Persona's 24x7 support coverage. He has an undergraduate degree in computer science, and in 2010 he started pursuing studies to earn an MBA.

Comments

  1. Peter says:

    Hi, Thanks for this post, I tried following the same steps outlined above. but was still getting this error in the import table space step: ERROR 1146 (42S02) at line 1: Table ‘test.mytesttable’ doesn’t exist

    Any ideas?
    I’m using the manajro linux OS

    thanks

  2. Michael Rikmas says:

    I have no idea…
    On other OS I see this message before discard namespace, but not before import.
    I didn’t try manajro linux OS but I’ll try to reproduce it and will write result here.

  3. Peter says:

    Hi,

    Just to give an update, I got it to work by running the commands while logged into mysql instead of using the mysql execute option with mysql -e

  4. Linas says:

    Thanks for the tutorial.
    The point is: you should backup your tables one by one. I mean that you need to drop the old table in the sandbox database before starting to backup the new one.

  5. MK_dir says:

    What is your my.cnf Configuration? Because after “alter table table_name import tablespace” i get allways an error:

    ERROR 2013 (HY000): Lost connection to MySQL server during query
    ERROR 2006 (HY000): MySQL server has gone away
    No connection. Trying to reconnect…
    ERROR 2002 (HY000): Can’t connect to local MySQL server through socket ‘/var/lib/mysql/mysql.sock’ (111)
    ERROR:
    Can’t connect to the server

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