mysqldump with WHERE id IN (SELECT …) yields table “was not locked” error

Question

I have 2 databases, with ~100,000 rows missing from the table field_collection_item from db1, which I\'d like to repair by exporting from db2

Answer 1

If your tables are MyISAM, the safest, easiest way to handle this is to pass the flag --lock-all-tables. If your tables are InnoDB then --single-transaction is better.

Answer 2

If you don't need a consistency guarantee, you can disable locking without single transaction by adding:

--lock-tables=false

I use this to do the same thing you're after (dumping subsets of the data) and on replication slaves that I can stop (making it consistent anyway).

An advantage over --single-transaction is that you can use/mix non-MVCC-engine tables.