I just released a new version of slim-attributes.  There are some small speed gains and some other minor changes from 0.4.1, but there are no big changes. Read more about slim-attributes at the slim-attributes homepage, or read on below. Introduction Slim-attributes is a small patch to the ActiveRecord Mysql adaptor that stops rails from immediately making ruby strings from the column names and data from your database queries. Because you probably don't need them all! So ruby strings are lazily created on demand - it's faster and uses less memory. And it drops directly in, requiring only the installation of a gem and adding 1 line to environment.rb. Measuring with just ActiveRecord code - fetching stuff from the database - we see anything up to a 50% (or more) speed increase, but it really depends on your system and environment, and what you are doing with the results from the database.  The more columns your tables have, the better the improvement will likely be.  Measure your own system and send me the results! Installation Try: or: then add this to environment.rb: Description Normally the mysql adaptor in Rails returns a hash of the data returned from the database, one hash per active record object returned by the query. The routine that generates these hashes is called all_hashes, and this is what we replace. The reason for overriding all_hashes is threefold:

• making a hash of each and every row returned from the database is slow
• rails makes frozen copies of each column name string (for the keys) which results in a great many strings which are not really needed
• we observe that it's not often that all the fields of rows fetched from the database are actually used

So this is an alternative implementation of all_hashes that returns a 'fake hash' which contains a hash of the column names (the same hash of names is used for every row), and also contains the row data in an area memcpy'd directly from the mysql API (which is much faster than creating ruby strings). The field contents are then instantiated into Ruby strings on demand - ruby strings are only made if you need them - when you ask for a particular attribute from the model object. Note that if you always look at all the columns when you fetch data from the database then this won't necessarily be faster that the unpatched mysql adapter.  But it won't be much slower either, and we do expect that most times not all the columns from a result set are accessed. Future development I speculate that further speed gains might be had through keeping the mysql result objects from mysql-ruby around, and not copying the data from them at all until it is needed. However, mysql-ruby limits the non freed result sets to just 20 before calling GC.start, so surgery inside mysql-ruby would be required to achieve this.