MySQL MYD and TMD files
I just recovered from a database issue.
While running a mysqldump of my databases I received an error. Running a check on that specific database told me that the comments.MYD file was not found.
Investigating on the system showed me that due to an error the filesystem containing /var/lib/mysql was mounted read-only. Running a fsck on that specific filesystem solved that error but didn’t fix my corrupted table.
phpMyAdmin showed that the table was in use and while performing a check or repair it complained about the missing file.
The comments.MYD file was indeed missing, but there was a comments.TMD file, which wasn’t there for all the other tables.
Moving this TMD file to MYD solved the issue. I could repair the table and the check is again successful.
During this problem wordpress didn’t complain but it just didn’t show my comments. But I have no clue what caused this problem.
July 29th, 2008
.TMD basically a temparory file of .MYD. it gets converted into .TMD if the data size of the table has exceeded the actual size of the data. in that case you can alter the table and increase the MAX size of the table.
About the comments, when you must have added the comments the table had already been converted into .TMD and when you repaired the table those comments were never entered.