diff options
Diffstat (limited to 'lib/gitlab/pagination/keyset/order.rb')
| -rw-r--r-- | lib/gitlab/pagination/keyset/order.rb | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/lib/gitlab/pagination/keyset/order.rb b/lib/gitlab/pagination/keyset/order.rb index cef3a7b291a..19d44ee69dd 100644 --- a/lib/gitlab/pagination/keyset/order.rb +++ b/lib/gitlab/pagination/keyset/order.rb @@ -139,6 +139,8 @@ module Gitlab verify_incoming_values!(values) + return use_composite_row_comparison(values) if composite_row_comparison_possible? + where_values = [] reversed_column_definitions = column_definitions.reverse @@ -187,6 +189,28 @@ module Gitlab private + def composite_row_comparison_possible? + !column_definitions.one? && + column_definitions.all?(&:not_nullable?) && + column_definitions.map(&:order_direction).uniq.one? # all columns uses the same order direction + end + + # composite row comparison works with NOT NULL columns and may use only one index scan given a proper index setup + # Example: (created_at, id) > ('2012-09-18 01:40:01+00', 15) + def use_composite_row_comparison(values) + columns = Arel::Nodes::Grouping.new(column_definitions.map(&:column_expression)) + values = Arel::Nodes::Grouping.new(column_definitions.map do |column_definition| + value = values[column_definition.attribute_name] + Arel::Nodes.build_quoted(value, column_definition.column_expression) + end) + + if column_definitions.first.ascending_order? + [columns.gt(values)] + else + [columns.lt(values)] + end + end + # Adds extra columns to the SELECT clause def apply_custom_projections(scope) additional_projections = column_definitions.select(&:add_to_projections).map do |column_definition| |