diff --git a/lib/redis_client/cluster/concurrent_worker/pooled.rb b/lib/redis_client/cluster/concurrent_worker/pooled.rb
index 8e92b72..ca29b91 100644
--- a/lib/redis_client/cluster/concurrent_worker/pooled.rb
+++ b/lib/redis_client/cluster/concurrent_worker/pooled.rb
@@ -11,8 +11,8 @@ module ConcurrentWorker
       # So it consumes memory 1 MB multiplied a number of workers.
       class Pooled
         IO_ERROR_NEVER = { IOError => :never }.freeze
-        IO_ERROR_ON_BLOCKING = { IOError => :on_blocking }.freeze
-        private_constant :IO_ERROR_NEVER, :IO_ERROR_ON_BLOCKING
+        IO_ERROR_IMMEDIATE = { IOError => :immediate }.freeze
+        private_constant :IO_ERROR_NEVER, :IO_ERROR_IMMEDIATE
 
         def initialize(size:)
           raise ArgumentError, "size must be positive: #{size}" unless size.positive?
@@ -73,7 +73,7 @@ def spawn_worker
           Thread.new(@q) do |q|
             Thread.handle_interrupt(IO_ERROR_NEVER) do
               loop do
-                Thread.handle_interrupt(IO_ERROR_ON_BLOCKING) do
+                Thread.handle_interrupt(IO_ERROR_IMMEDIATE) do
                   q.pop.exec
                 end
               end
diff --git a/lib/redis_client/cluster/pub_sub.rb b/lib/redis_client/cluster/pub_sub.rb
index 4cda609..dea2f6d 100644
--- a/lib/redis_client/cluster/pub_sub.rb
+++ b/lib/redis_client/cluster/pub_sub.rb
@@ -8,8 +8,8 @@ class Cluster
     class PubSub
       class State
         IO_ERROR_NEVER = { IOError => :never }.freeze
-        IO_ERROR_ON_BLOCKING = { IOError => :on_blocking }.freeze
-        private_constant :IO_ERROR_NEVER, :IO_ERROR_ON_BLOCKING
+        IO_ERROR_IMMEDIATE = { IOError => :immediate }.freeze
+        private_constant :IO_ERROR_NEVER, :IO_ERROR_IMMEDIATE
 
         def initialize(client, queue)
           @client = client
@@ -45,12 +45,12 @@ def spawn_worker(client, queue)
           Thread.new(client, queue, nil) do |pubsub, q, prev_err|
             Thread.handle_interrupt(IO_ERROR_NEVER) do
               loop do
-                Thread.handle_interrupt(IO_ERROR_ON_BLOCKING) { q << pubsub.next_event }
+                Thread.handle_interrupt(IO_ERROR_IMMEDIATE) { q << pubsub.next_event }
                 prev_err = nil
               rescue StandardError => e
                 next sleep 0.005 if e.instance_of?(prev_err.class) && e.message == prev_err&.message
 
-                Thread.handle_interrupt(IO_ERROR_ON_BLOCKING) { q << e }
+                Thread.handle_interrupt(IO_ERROR_IMMEDIATE) { q << e }
                 prev_err = e
               end
             end