Clear all connections once master recovers.

lib/active_record/connection_adapters/postgresql_fallback_adapter.rb

@@ -80,6 +80,7 @@ class PostgreSQLFallbackHandler
               self.master_up(key)
               disable_readonly_mode
               Sidekiq.unpause!
+              clear_connections
             end
           rescue => e
             logger.warn "#{log_prefix}: Connection to master PostgreSQL server failed with '#{e.message}'"

spec/components/active_record/connection_adapters/postgresql_fallback_adapter_spec.rb

@@ -36,7 +36,6 @@ describe ActiveRecord::ConnectionHandling do
 
   after do
     postgresql_fallback_handler.setup!
-    postgresql_fallback_handler.clear_connections
     Discourse.disable_readonly_mode(Discourse::PG_READONLY_MODE_KEY)
   end