perf: add an environment variable to be able to configure a data type of slots and nodes mapping (#283)

Author: supercaracal

lib/redis_client/cluster/node.rb

@@ -17,6 +17,7 @@ class Node
       MIN_SLOT = 0
       MAX_SLOT = SLOT_SIZE - 1
       MAX_STARTUP_SAMPLE = Integer(ENV.fetch('REDIS_CLIENT_MAX_STARTUP_SAMPLE', 3))
+      USE_CHAR_ARRAY_SLOT = Integer(ENV.fetch('REDIS_CLIENT_USE_CHAR_ARRAY_SLOT', 1)) == 1 # less memory consumption, but slow
       IGNORE_GENERIC_CONFIG_KEYS = %i[url host port path].freeze
       DEAD_FLAGS = %w[fail? fail handshake noaddr noflags].freeze
       ROLE_FLAGS = %w[master slave].freeze
@@ -310,7 +311,7 @@ def build_slot_node_mappings(node_info_list)
       end
 
       def make_array_for_slot_node_mappings(node_info_list)
-        return Array.new(SLOT_SIZE) if node_info_list.count(&:primary?) > 256
+        return Array.new(SLOT_SIZE) if !USE_CHAR_ARRAY_SLOT || node_info_list.count(&:primary?) > 256
 
         primary_node_keys = node_info_list.select(&:primary?).map(&:node_key)
         ::RedisClient::Cluster::Node::CharArray.new(SLOT_SIZE, primary_node_keys)

test/ips_slot_node_mapping.rb

@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require 'benchmark/ips'
+require 'redis_cluster_client'
+
+module IpsSlotNodeMapping
+  ELEMENTS = %w[foo bar baz].freeze
+  SIZE = ::RedisClient::Cluster::Node::SLOT_SIZE
+
+  module_function
+
+  def run
+    ca = ::RedisClient::Cluster::Node::CharArray.new(SIZE, ELEMENTS)
+    arr = Array.new(SIZE)
+
+    print_letter('Mappings between slots and nodes')
+    fullfill(ca)
+    fullfill(arr)
+    bench({ ca.class.name.split('::').last => ca, arr.class.name => arr })
+  end
+
+  def print_letter(title)
+    print "################################################################################\n"
+    print "# #{title}\n"
+    print "################################################################################\n"
+    print "\n"
+  end
+
+  def fullfill(arr)
+    SIZE.times { |i| arr[i] = ELEMENTS[i % ELEMENTS.size] }
+  end
+
+  def bench(subjects)
+    Benchmark.ips do |x|
+      x.time = 5
+      x.warmup = 1
+
+      subjects.each do |subtitle, arr|
+        x.report(subtitle) do
+          arr[0]
+        end
+      end
+
+      x.compare!
+    end
+  end
+end
+
+IpsSlotNodeMapping.run

test/redis_client/cluster/test_node.rb

@@ -488,7 +488,7 @@ def test_make_array_for_slot_node_mappings_optimized
 
         want = node_info_list.first.node_key
         got = @test_node.send(:make_array_for_slot_node_mappings, node_info_list)
-        assert_instance_of(::RedisClient::Cluster::Node::CharArray, got)
+        assert_instance_of(::RedisClient::Cluster::Node::USE_CHAR_ARRAY_SLOT ? ::RedisClient::Cluster::Node::CharArray : Array, got)
         ::RedisClient::Cluster::Node::SLOT_SIZE.times do |i|
           got[i] = want
           assert_equal(want, got[i], "Case: #{i}")
@@ -521,19 +521,19 @@ def test_make_array_for_slot_node_mappings_max_shard_size
         end
 
         got = @test_node.send(:make_array_for_slot_node_mappings, node_info_list)
-        assert_instance_of(::RedisClient::Cluster::Node::CharArray, got)
+        assert_instance_of(::RedisClient::Cluster::Node::USE_CHAR_ARRAY_SLOT ? ::RedisClient::Cluster::Node::CharArray : Array, got)
 
         ::RedisClient::Cluster::Node::SLOT_SIZE.times { |i| got[i] = node_info_list.first.node_key }
 
         got[0] = 'newbie:6379'
         assert_equal('newbie:6379', got[0])
-        assert_raises(RangeError) { got[0] = 'zombie:6379' }
+        assert_raises(RangeError) { got[0] = 'zombie:6379' } if ::RedisClient::Cluster::Node::USE_CHAR_ARRAY_SLOT
 
-        assert_raises(IndexError) { got[-1] = 'newbie:6379' }
-        assert_raises(IndexError) { got[-1] }
+        assert_raises(IndexError) { got[-1] = 'newbie:6379' } if ::RedisClient::Cluster::Node::USE_CHAR_ARRAY_SLOT
+        assert_raises(IndexError) { got[-1] } if ::RedisClient::Cluster::Node::USE_CHAR_ARRAY_SLOT
 
         got[16_384] = 'newbie:6379'
-        assert_nil(got[16_384])
+        assert_nil(got[16_384]) if ::RedisClient::Cluster::Node::USE_CHAR_ARRAY_SLOT
       end
 
       def test_build_replication_mappings_regular