# Estimate the amount of documents that would be indexed. Not exact!
# @returns [Integer]
defestimate!
ActiveRecord::Base.connection_pool.with_connection{|connection|connection.select_one("SELECT reltuples AS estimate FROM pg_class WHERE relname = '#{index.adapter.target.table_name}'")['estimate'].to_i}
end
# Import data from the database into the index
defimport!
raiseNotImplementedError
end
# Remove documents from the index that no longer exist in the database