Reconfigure the Geo tracking database pool size when running as Sidekiq

changelogs/unreleased-ee/3809-geo-sidekiq-pool.yml

+---
+title: Reconfigure the Geo tracking database pool size when running as Sidekiq
+merge_request: 3181
+author:
+type: fixed

config/initializers/sidekiq.rb

@@ -52,6 +52,14 @@ Sidekiq.configure_server do |config|
   ActiveRecord::Base.establish_connection(config)
   Rails.logger.debug("Connection Pool size for Sidekiq Server is now: #{ActiveRecord::Base.connection.pool.instance_variable_get('@size')}")
 
+  # EE only
+  if Gitlab::Geo.geo_database_configured?
+    Rails.configuration.geo_database['pool'] = Sidekiq.options[:concurrency]
+    Geo::TrackingBase.establish_connection(Rails.configuration.geo_database)
+
+    Rails.logger.debug("Connection Pool size for Sidekiq Server is now: #{Geo::TrackingBase.connection_pool.size} (Geo tracking database)")
+  end
+
   # Avoid autoload issue such as 'Mail::Parsers::AddressStruct'
   # https://github.com/mikel/mail/issues/912#issuecomment-214850355
   Mail.eager_autoload!