X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/9090c60b28de593b8bb2ce606a9ab35b62b57608..0eb72b526bf8bbb011551ecf019f604e17a534f1:/services/api/app/controllers/application_controller.rb

diff --git a/services/api/app/controllers/application_controller.rb b/services/api/app/controllers/application_controller.rb
index 6ba334fc85..3a66f5328d 100644
--- a/services/api/app/controllers/application_controller.rb
+++ b/services/api/app/controllers/application_controller.rb
@@ -1,3 +1,7 @@
+# Copyright (C) The Arvados Authors. All rights reserved.
+#
+# SPDX-License-Identifier: AGPL-3.0
+
 require 'safe_json'
 
 module ApiTemplateOverride
@@ -83,7 +87,9 @@ class ApplicationController < ActionController::Base
   end
 
   def index
-    @objects.uniq!(&:id) if @select.nil? or @select.include? "id"
+    if @select.nil? || @select.include?("id")
+      @objects = @objects.uniq(&:id)
+    end
     if params[:eager] and params[:eager] != '0' and params[:eager] != 0 and params[:eager] != ''
       @objects.each(&:eager_load_associations)
     end
@@ -176,18 +182,9 @@ class ApplicationController < ActionController::Base
            }.merge opts)
   end
 
-  def self.limit_index_columns_read
-    # This method returns a list of column names.
-    # If an index request reads that column from the database,
-    # find_objects_for_index will only fetch objects until it reads
-    # max_index_database_read bytes of data from those columns.
-    []
-  end
-
   def find_objects_for_index
     @objects ||= model_class.readable_by(*@read_users)
     apply_where_limit_order_params
-    limit_database_read if (action_name == "index")
   end
 
   def apply_filters model_class=nil
@@ -276,15 +273,21 @@ class ApplicationController < ActionController::Base
     @objects = @objects.uniq(@distinct) if not @distinct.nil?
   end
 
-  def limit_database_read
-    limit_columns = self.class.limit_index_columns_read
+  # limit_database_read ensures @objects (which must be an
+  # ActiveRelation) does not return too many results to fit in memory,
+  # by previewing the results and calling @objects.limit() if
+  # necessary.
+  def limit_database_read(model_class:)
+    return if @limit == 0 || @limit == 1
+    model_class ||= self.model_class
+    limit_columns = model_class.limit_index_columns_read
     limit_columns &= model_class.columns_for_attributes(@select) if @select
     return if limit_columns.empty?
     model_class.transaction do
       limit_query = @objects.
-        except(:select).
+        except(:select, :distinct).
         select("(%s) as read_length" %
-               limit_columns.map { |s| "octet_length(#{s})" }.join(" + "))
+               limit_columns.map { |s| "octet_length(#{model_class.table_name}.#{s})" }.join(" + "))
       new_limit = 0
       read_total = 0
       limit_query.each do |record|
@@ -292,12 +295,12 @@ class ApplicationController < ActionController::Base
         read_total += record.read_length.to_i
         if read_total >= Rails.configuration.max_index_database_read
           new_limit -= 1 if new_limit > 1
+          @limit = new_limit
           break
         elsif new_limit >= @limit
           break
         end
       end
-      @limit = new_limit
       @objects = @objects.limit(@limit)
       # Force @objects to run its query inside this transaction.
       @objects.each { |_| break }
@@ -459,7 +462,10 @@ class ApplicationController < ActionController::Base
   end
   accept_param_as_json :reader_tokens, Array
 
-  def object_list
+  def object_list(model_class:)
+    if @objects.respond_to?(:except)
+      limit_database_read(model_class: model_class)
+    end
     list = {
       :kind  => "arvados##{(@response_resource_name || resource_name).camelize(:lower)}List",
       :etag => "",
@@ -483,7 +489,7 @@ class ApplicationController < ActionController::Base
   end
 
   def render_list
-    send_json object_list
+    send_json object_list(model_class: self.model_class)
   end
 
   def remote_ip