How to recover mysql db from .myd, .myi, .frm files

Question

How to restore one of my mysql db from .myd, .myi, .frm files?

Answer 1

You can copy the files into an appropriately named subdirectory directory of the data folder as long as it is the EXACT same version of mySQL and you have retained all of the associated files in that directory. If you don't have all the files, I'm pretty sure you're going to have issues.

Answer 2

If these are MyISAM tables, then plopping the .FRM, .MYD, and .MYI files into a database directory (e.g., /var/lib/mysql/dbname) will make that table available. It doesn't have to be the same database as they came from, the same server, the same MySQL version, or the same architecture.

Actually, you probably just need the .FRM (table structure) and .MYD (table data), but you'll have to repair table to rebuild the .MYI (indexes).

The only constraint is that if you're downgrading, you'd best check the release notes (and probably run repair table). Newer MySQL versions add features, of course.

[Although it should be obvious, if you mix and match tables, the integrity of relationships between those tables is your problem; MySQL won't care, but your application and your users may. Also, this method does not work at all for InnoDB tables. Only MyISAM, but considering the files you have, you have MyISAM]

Answer 3

I think .myi you can repair from inside mysql.

If you see these type of error messages from MySQL: Database failed to execute query (query) 1016: Can't open file: 'sometable.MYI'. (errno: 145) Error Msg: 1034: Incorrect key file for table: 'sometable'. Try to repair it thenb you probably have a crashed or corrupt table.

You can check and repair the table from a mysql prompt like this:

check table sometable;
+------------------+-------+----------+----------------------------+
| Table | Op | Msg_type | Msg_text | 
+------------------+-------+----------+----------------------------+ 
| yourdb.sometable | check | warning | Table is marked as crashed | 
| yourdb.sometable | check | status | OK | 
+------------------+-------+----------+----------------------------+ 

repair table sometable;
+------------------+--------+----------+----------+ 
| Table | Op | Msg_type | Msg_text | 
+------------------+--------+----------+----------+ 
| yourdb.sometable | repair | status | OK | 
+------------------+--------+----------+----------+

and now your table should be fine:

check table sometable;
+------------------+-------+----------+----------+ 
| Table | Op | Msg_type | Msg_text |
+------------------+-------+----------+----------+ 
| yourdb.sometable | check | status | OK |
+------------------+-------+----------+----------+

Answer 4

One thing to note:

The .FRM file has your table structure in it, and is specific to your MySQL version.

The .MYD file is NOT specific to version, at least not minor versions.

The .MYI file is specific, but can be left out and regenerated with REPAIR TABLE like the other answers say.

The point of this answer is to let you know that if you have a schema dump of your tables, then you can use that to generate the table structure, then replace those .MYD files with your backups, delete the MYI files, and repair them all. This way you can restore your backups to another MySQL version, or move your database altogether without using mysqldump. I've found this super helpful when moving large databases.

Answer 5

Note that if you want to rebuild the MYI file then the correct use of REPAIR TABLE is:

REPAIR TABLE sometable USE_FRM;

Otherwise you will probably just get another error.

Answer 6

Hey, try this link:

http://forums.devshed.com/mysql-help-4/mysql-installation-problems-197509.html

It says to rename the ib_* files. I have done it and it gave me back the db.