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javiercr/gist:9722206

Created March 23, 2014 12:06
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Slow ActiveRecord query with custom SQL and will_paginate
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gistfile1.rb
@messages = Message.includes(:from_user, :to_user, :parent)
.where(
"messages.id IN (
SELECT MAX(id) FROM messages GROUP BY COALESCE(parent_id, id) ORDER BY id DESC
)"
).order("messages.id DESC").scoped
@messages = @messages.paginate(page: params[:page])
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