a 'safe' way to move data?

[Ian P. Christian]

I'm trying to move data between 2 tables.

 > INSERT INTO new_table SELECT * FROM old_table LIMIT 50000;
 > DELETE FROM old_table LIMIT 50000;

This is the only process that deletes data from old_table, can I be 
*sure* that the limit in these 2 queries will address the same data set?

(if I don't limit to small numbers in the LIMIT, I/O gets too high, so 
I'm moving data slowly in batches)

Thanks,

-- 
Ian P. Christian ~ http://pookey.co.uk