Improve performance of the solr query used to generate the advanced s…

…earch form

Running this locally against the production solr sped the solr query up from
a median 10,691 ms to a median 1,851 ms.

This removes several potentially expensive parameters from the solr query we
send to generate the advanced search page:
* facet.query
* facet.pivot
* stats
* stats.field
* facet.field, except for the facet field values we need to retrieve to render
  the advanced search form

Since the logic is different on the numismatics form vs advanced form, this commit
splits them into two separate search builders.

app/controllers/catalog_controller.rb

@@ -841,8 +841,10 @@ def basic_response
     end
 
     def search_service_context
-      if %w[advanced_search numismatics].include? action_name
+      if action_name == 'advanced_search'
         { search_builder_class: AdvancedFormSearchBuilder }
+      elsif action_name == 'numismatics'
+        { search_builder_class: NumismaticsFormSearchBuilder }
       else
         return {} unless Flipflop.multi_algorithm?
         return {} unless configurable_search_builder_class # use default if none specified

app/models/advanced_form_search_builder.rb

@@ -2,7 +2,7 @@
 # This class is responsible for building a solr query
 # that renders an advanced search form
 class AdvancedFormSearchBuilder < SearchBuilder
-  self.default_processor_chain += %i[do_not_limit_languages]
+  self.default_processor_chain += %i[do_not_limit_languages only_request_advanced_facets]
 
   def do_not_limit_languages(solr_params)
     solr_params.update(solr_params) do |key, value|
@@ -13,4 +13,9 @@ def do_not_limit_languages(solr_params)
       end
     end
   end
+
+  def only_request_advanced_facets(solr_params)
+    solr_params['facet.field'] = blacklight_config.facet_fields.values.select(&:include_in_advanced_search).map(&:key)
+    %w[facet.pivot facet.query stats stats.field].each { |unneeded_field| solr_params.delete unneeded_field }
+  end
 end

app/models/numismatics_form_search_builder.rb

@@ -0,0 +1,2 @@
+class NumismaticsFormSearchBuilder < SearchBuilder
+end

spec/models/advanced_form_search_builder_spec.rb

@@ -29,4 +29,46 @@
       end.not_to(change { solr_params })
     end
   end
+
+  describe '#only_request_advanced_facets' do
+    let(:blacklight_config) { CatalogController.blacklight_config }
+
+    it 'removes unnecessary facet.field entries' do
+      builder.with({ action: 'advanced_search' })
+      solr_params = { "facet.field" => %w[genre_facet subject_era_facet geographic_facet] }
+
+      builder.only_request_advanced_facets(solr_params)
+
+      expect(solr_params['facet.field']).not_to include 'genre_facet'
+      expect(solr_params['facet.field']).not_to include 'subject_era_facet'
+      expect(solr_params['facet.field']).not_to include 'geographic_facet'
+    end
+
+    it 'adds the needed facet.field entries' do
+      builder.with({ action: 'advanced_search' })
+      solr_params = { "facet.field" => %w[genre_facet subject_era_facet geographic_facet] }
+
+      builder.only_request_advanced_facets(solr_params)
+
+      expect(solr_params['facet.field']).to include 'language_facet'
+    end
+
+    it 'removes unneeded params' do
+      builder.with({ action: 'advanced_search' })
+      solr_params = {
+        "facet.pivot" => %w[lc_1letter_facet lc_rest_facet],
+        "facet.query" => ['cataloged_tdt:[NOW/DAY-7DAYS TO NOW/DAY+1DAY]', 'cataloged_tdt:[NOW/DAY-14DAYS TO NOW/DAY+1DAY]'],
+        "stats" => true,
+        "stats.field" => "pub_date_start_sort"
+      }
+
+      builder.only_request_advanced_facets(solr_params)
+
+      expect(solr_params.keys).not_to include 'facet.query'
+      expect(solr_params.keys).not_to include 'facet.pivot'
+      expect(solr_params.keys).not_to include 'stats'
+      expect(solr_params.keys).not_to include 'stats.field'
+      expect(solr_params.keys).to include 'facet.field'
+    end
+  end
 end

spec/requests/advanced_search_spec.rb

@@ -2,6 +2,12 @@
 
 require 'rails_helper'
 
+RSpec::Matchers.define :request_without_facet_queries do
+  match do |actual|
+    actual[:params].keys.exclude? 'facet.query'
+  end
+end
+
 describe 'Orangelight advanced search', type: :request, advanced_search: true do
   before do
     stub_holding_locations
@@ -11,4 +17,15 @@
     get '/advanced?f[subject_facet][]=United+Nations-Decision+making'
     expect(response.status).to eq(200)
   end
+
+  it 'does not send complex facet queries to solr when rendering advanced search form' do
+    # rubocop:disable RSpec/AnyInstance
+    expect_any_instance_of(RSolr::Client).to receive(:send_and_receive)
+      .with('select', request_without_facet_queries)
+      .once
+      .and_call_original
+    # rubocop:enable RSpec/AnyInstance
+
+    get '/advanced'
+  end
 end