Lower batch size on ETL tasks

When running the ETL rake tasks we sometimes might run into errors
because the pods run out of memory. Lowering the batch size should
hopefully help avoid those errors.

app/domain/etl/feedex/processor.rb

@@ -18,7 +18,7 @@ def process
 
 private
 
-  BATCH_SIZE = 10_000
+  BATCH_SIZE = 5_000
 
   def extract_events
     batch = 1

app/domain/etl/ga/internal_search_processor.rb

@@ -25,7 +25,7 @@ def extract_events
     batch = 1
     Etl::GA::InternalSearchService.find_in_batches(date:) do |events|
       log process: :ga, message: "Processing #{events.length} events in batch #{batch}"
-      Events::GA.import(events, batch_size: 10_000)
+      Events::GA.import(events, batch_size: 5_000)
       batch += 1
     end
   end

app/domain/etl/ga/user_feedback_processor.rb

@@ -25,7 +25,7 @@ def extract_events
     batch = 1
     Etl::GA::UserFeedbackService.find_in_batches(date:) do |events|
       log process: :ga, message: "Processing #{events.length} events in batch #{batch}"
-      Events::GA.import(events, batch_size: 10_000)
+      Events::GA.import(events, batch_size: 5_000)
       batch += 1
     end
   end

app/domain/etl/ga/views_and_navigation_processor.rb

@@ -25,7 +25,7 @@ def extract_events
     batch = 1
     Etl::GA::ViewsAndNavigationService.find_in_batches(date:) do |events|
       log process: :ga, message: "Processing #{events.length} events in batch #{batch}"
-      Events::GA.import(events, batch_size: 10_000)
+      Events::GA.import(events, batch_size: 5_000)
       batch += 1
     end
   end

app/domain/etl/main/metrics_processor.rb

@@ -27,7 +27,7 @@ def create_metrics
         log process: :metrics, message: "about to get the Dimensions::Date"
         dimensions_date = Dimensions::Date.find_existing_or_create(date)
         log process: :metrics, message: "got the Dimensions::Date"
-        Dimensions::Edition.live.find_in_batches(batch_size: 10_000)
+        Dimensions::Edition.live.find_in_batches(batch_size: 5_000)
           .with_index do |batch, index|
           log process: :metrics, message: "processing #{batch.length} items in batch #{index}"
           values = batch.pluck(:id).map do |value|

spec/integration/master/daily_metrics_spec.rb

@@ -170,7 +170,7 @@ def stub_feedex_response
       'page_size': 3,
     }.to_json
 
-    stub_request(:get, "http://support-api.dev.gov.uk/feedback-by-day/#{yesterday}?page=1&per_page=10000")
+    stub_request(:get, "http://support-api.dev.gov.uk/feedback-by-day/#{yesterday}?page=1&per_page=5000")
       .to_return(status: 200, body: response, headers: {})
   end
 end