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# add this file as config/initializers/will_paginate_postgresql_count.rb
# in a Rails application
module WillPaginate
module Finder
module ClassMethods
# add '1=1' to paginate conditions as marker such that the select from the pg_class
# is used to approximate simple rows count, e.g.
# Foo.paginate(:page => params[:page], :conditions => "1=1")
def wp_count_with_postgresql(options, args, finder, &block)
if options[:conditions] == ["1=1"] || options[:conditions] == "1=1"
# counting rows in PostgreSQL is slow so use the pg_class table for
# approximate rows count on simple selects
# http://wiki.postgresql.org/wiki/Slow_Counting
# http://www.varlena.com/GeneralBits/120.php
self.count_by_sql "SELECT (reltuples)::integer FROM pg_class r WHERE relkind = 'r' AND relname = '#{self.table_name}'"
else
wp_count_without_postgresql(options, args, finder, &block)
end
end
alias_method_chain :wp_count, :postgresql
end
end
end
@kineticac

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commented Dec 14, 2010

There's a problem with the alias_method_chain. Since wp_count is protected, it doesn't seem to work. here's the error:

...aliasing.rb:33:in alias_method': undefined methodwp_count' for module `WillPaginate::Finder::ClassMethods' (NameError)

Any ideas how to alias the protected method?

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