Module: ActiverecordCoveringIndex::PostgreSQLAdapter

Defined in:
lib/activerecord-covering-index/postgresql_adapter.rb

Instance Method Summary collapse

Instance Method Details

#add_index_options(table_name, column_name, name: nil, internal: false, **options) ⇒ Object 



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# File 'lib/activerecord-covering-index/postgresql_adapter.rb', line 13

def add_index_options(table_name, column_name, name: nil, internal: false, **options)
  options.assert_valid_keys(:unique, :length, :order, :opclass, :where, :type, :using, :comment, :algorithm, :if_not_exists, :include)

  options[:name] = name if name
  options[:internal] = internal
  non_key_columns = options.delete(:include)

  original_index_options = super(table_name, column_name, **options)

  if original_index_options.first.is_a?(String)
    index_name, index_type, index_columns, index_options, algorithm, using, comment = original_index_options

    if non_key_columns && supports_covering_index?
      non_key_columns = [non_key_columns] if non_key_columns.is_a?(Symbol)
      non_key_columns = quoted_columns_for_index(non_key_columns, {}).join(", ")

      index_options = " INCLUDE (#{non_key_columns})" + index_options
    end

    [index_name, index_type, index_columns, index_options, algorithm, using, comment]
  else
    index, algorithm, if_not_exists = original_index_options

    index_with_include = ActiveRecord::ConnectionAdapters::IndexDefinition.new(
      index.table,
      index.name,
      index.unique,
      index.columns,
      lengths: index.lengths,
      orders: index.orders,
      opclasses: index.opclasses,
      where: index.where,
      type: index.type,
      using: index.using,
      comment: index.comment,
      include: non_key_columns
    )

    [index_with_include, algorithm, if_not_exists]
  end
end

#indexes(table_name) ⇒ Object 



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# File 'lib/activerecord-covering-index/postgresql_adapter.rb', line 55

def indexes(table_name)
  scope = quoted_scope(table_name)

  result = query(<<~SQL, "SCHEMA")
    SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid,
                    pg_catalog.obj_description(i.oid, 'pg_class') AS comment, d.indnkeyatts
    FROM pg_class t
    INNER JOIN pg_index d ON t.oid = d.indrelid
    INNER JOIN pg_class i ON d.indexrelid = i.oid
    LEFT JOIN pg_namespace n ON n.oid = i.relnamespace
    WHERE i.relkind IN ('i', 'I')
      AND d.indisprimary = 'f'
      AND t.relname = #{scope[:name]}
      AND n.nspname = #{scope[:schema]}
    ORDER BY i.relname
  SQL

  result.map do |row|
    index_name = row[0]
    unique = row[1]
    indkey = row[2].split(" ").map(&:to_i)
    inddef = row[3]
    oid = row[4]
    comment = row[5]
    indnkeyatts = row[6]

    using, expressions, _, where = inddef.scan(/ USING (\w+?) \((.+?)\)(?: INCLUDE \((.+?)\))?(?: WHERE (.+))?\z/m).flatten

    orders = {}
    opclasses = {}

    columns = Hash[query(<<~SQL, "SCHEMA")].values_at(*indkey)
      SELECT a.attnum, a.attname
      FROM pg_attribute a
      WHERE a.attrelid = #{oid}
      AND a.attnum IN (#{indkey.join(",")})
    SQL

    non_key_columns = columns.pop(columns.count - indnkeyatts)

    if indkey.include?(0)
      columns = expressions
    else
      # add info on sort order (only desc order is explicitly specified, asc is the default)
      # and non-default opclasses
      expressions.scan(/(?<column>\w+)"?\s?(?<opclass>\w+_ops)?\s?(?<desc>DESC)?\s?(?<nulls>NULLS (?:FIRST|LAST))?/).each do |column, opclass, desc, nulls|
        opclasses[column] = opclass.to_sym if opclass
        if nulls
          orders[column] = [desc, nulls].compact.join(" ")
        else
          orders[column] = :desc if desc
        end
      end
    end

    ActiveRecord::ConnectionAdapters::IndexDefinition.new(
      table_name,
      index_name,
      unique,
      columns,
      orders: orders,
      opclasses: opclasses,
      where: where,
      using: using.to_sym,
      comment: comment.presence,
      include: non_key_columns
    )
  end
end

#supports_covering_index? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/activerecord-covering-index/postgresql_adapter.rb', line 5

def supports_covering_index?
  if respond_to?(:database_version) # ActiveRecord 6+
    database_version >= 110_000
  else
    postgresql_version >= 110_000
  end
end