diff --git a/lib/active_record/connection_adapters/seamless_database_pool_adapter.rb b/lib/active_record/connection_adapters/seamless_database_pool_adapter.rb
index ee0490d..340f1f5 100755
--- a/lib/active_record/connection_adapters/seamless_database_pool_adapter.rb
+++ b/lib/active_record/connection_adapters/seamless_database_pool_adapter.rb
@@ -24,7 +24,7 @@ def seamless_database_pool_connection(config)
         config[:read_pool]&.each_with_index do |read_config, i|
           read_config = default_config.merge(read_config).with_indifferent_access
           if (url = read_config.delete(:url))
-            master_config.merge!(ActiveRecord::DatabaseConfigurations::ConnectionUrlResolver.new(url).to_hash)
+            read_config.merge!(ActiveRecord::DatabaseConfigurations::ConnectionUrlResolver.new(url).to_hash)
           end
           read_config[:pool_weight] = read_config[:pool_weight].to_i
           next unless read_config[:pool_weight] > 0