Re: Queries returning large number of rows

[Björn Steinbrink]

For that query, the index will not work. MySQL can only use an index if you use a prefix of it. So your index on (current_entry, previous_entry) will work for:
... WHERE current_entry LIKE 'whatever%';
... WHERE current_entry LIKE 'foo%' AND previous_entry like 'bar%'
But not for:
... WHERE previous_entry LIKE 'whatever%'

For the latter you need an index that starts with previous_entry.