On Mar 14, 6:39 pm, John Smith <[email protected]> wrote: > Matt Jones wrote: > > On Mar 11, 4:50 am, John Smith <[email protected]> wrote: > >> I have a simple table inherance, with an upper class GeneralElement. A > >> class that inherits is Activity: > >> class Activity < GeneralElement > >> ... > >> end > > >> The GeneralElement table is very big (about 2.000.000 rows!). Other > >> classes that inherit from GeneralElement return queries very fast, but > >> Activity.last is very slow. I have added indexes to id and type, but it > >> has no effect. What can I do? > > > You may want to grab the query that Activity.last is using, and try > > running it through 'EXPLAIN' to see what it's looking for. Have you > > defined an order (via default_scope, for instance) on Activity? You > > might need to have an index on that field together with 'type' to get > > right behavior. > > > --Matt Jones > > I have added an index to the type column; but maybe it's possible to add > a special index to both the id and type column at the same time. How > could I do this?
add_index will accept an array of columns: add_index :general_elements, [:type, :id] --Matt Jones -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
