Add pool_concurrency_test manual spec

Add MT connection count without Mutex

spec/dummy_driver.cr

@@ -1,4 +1,3 @@
-require "spec"
 require "../src/db"
 
 class DummyDriver < DB::Driver
@@ -17,20 +16,37 @@ class DummyDriver < DB::Driver
   end
 
   class DummyConnection < DB::Connection
+    @@connections = [] of DummyConnection
+    @@connections_count = Atomic(Int32).new(0)
+
     def initialize(options : DB::Connection::Options)
       super(options)
       Fiber.yield
+      @@connections_count.add(1)
       @connected = true
-      @@connections ||= [] of DummyConnection
-      @@connections.not_nil! << self
+      {% unless flag?(:preview_mt) %}
+        # @@connections is only used in single-threaded mode in specs
+        # for benchmarks we want to avoid the overhead of synchronizing this array
+        @@connections << self
+      {% end %}
+    end
+
+    def self.connections_count
+      @@connections_count.get
     end
 
     def self.connections
-      @@connections.not_nil!
+      {% if flag?(:preview_mt) %}
+        raise "DummyConnection.connections is only available in single-threaded mode"
+      {% end %}
+      @@connections
     end
 
     def self.clear_connections
-      @@connections.try &.clear
+      {% if flag?(:preview_mt) %}
+        raise "DummyConnection.clear_connections is only available in single-threaded mode"
+      {% end %}
+      @@connections.clear
     end
 
     def build_prepared_statement(query) : DB::Statement
@@ -117,17 +133,30 @@ class DummyDriver < DB::Driver
   end
 
   class DummyStatement < DB::Statement
+    @@statements_count = Atomic(Int32).new(0)
+    @@statements_exec_count = Atomic(Int32).new(0)
     property params
 
     def initialize(connection, command : String, @prepared : Bool)
       @params = Hash(Int32 | String, DB::Any | Array(DB::Any)).new
       super(connection, command)
+      @@statements_count.add(1)
       raise DB::Error.new(command) if command == "syntax error"
     end
 
+    def self.statements_count
+      @@statements_count.get
+    end
+
+    def self.statements_exec_count
+      @@statements_exec_count.get
+    end
+
     protected def perform_query(args : Enumerable) : DB::ResultSet
       assert_not_closed!
 
+      @@statements_exec_count.add(1)
+
       Fiber.yield
       @connection.as(DummyConnection).check
       set_params args
@@ -137,6 +166,8 @@ class DummyDriver < DB::Driver
     protected def perform_exec(args : Enumerable) : DB::ExecResult
       assert_not_closed!
 
+      @@statements_exec_count.add(1)
+
       @connection.as(DummyConnection).check
       set_params args
       raise DB::Error.new("forced exception due to query") if command == "raise"

spec/manual/pool_concurrency_test.cr

@@ -0,0 +1,68 @@
+# This file is to be executed as:
+#
+# % crystal run --release [-Dpreview_mt] ./spec/manual/pool_concurrency_test.cr -- --options="max_pool_size=5" --duration=30 --concurrency=4
+#
+#
+
+require "option_parser"
+require "../dummy_driver"
+require "../../src/db"
+
+options = ""
+duration = 3
+concurrency = 4
+
+OptionParser.parse do |parser|
+  parser.banner = "Usage: pool_concurrency_test [arguments]"
+  parser.on("-o", "--options=VALUE", "Connection string options") { |v| options = v }
+  parser.on("-d", "--duration=SECONDS", "Specifies the duration in seconds") { |v| duration = v.to_i }
+  parser.on("-c", "--concurrency=VALUE", "Specifies the concurrent requests to perform") { |v| concurrency = v.to_i }
+  parser.on("-h", "--help", "Show this help") do
+    puts parser
+    exit
+  end
+  parser.invalid_option do |flag|
+    STDERR.puts "ERROR: #{flag} is not a valid option."
+    STDERR.puts parser
+    exit(1)
+  end
+end
+
+multi_threaded = {% if flag?(:preview_mt) %} ENV["CRYSTAL_WORKERS"]?.try(&.to_i?) || 4 {% else %} false {% end %}
+release = {% if flag?(:release) %} true {% else %} false {% end %}
+
+if !release
+  puts "WARNING: This should be run in release mode."
+end
+
+db = DB.open "dummy://host?#{options}"
+
+start_time = Time.monotonic
+
+puts "Starting test for #{duration} seconds..."
+
+concurrency.times do
+  spawn do
+    loop do
+      db.scalar "1"
+      Fiber.yield
+    end
+  end
+end
+
+sleep duration.seconds
+
+end_time = Time.monotonic
+
+puts "          Options : #{options}"
+puts "   Duration (sec) : #{duration} (actual #{end_time - start_time})"
+puts "      Concurrency : #{concurrency}"
+puts "   Multi Threaded : #{multi_threaded ? "Yes (#{multi_threaded})" : "No"}"
+puts "Total Connections : #{DummyDriver::DummyConnection.connections_count}"
+puts " Total Statements : #{DummyDriver::DummyStatement.statements_count}"
+puts "    Total Queries : #{DummyDriver::DummyStatement.statements_exec_count}"
+puts "Throughtput (q/s) : #{DummyDriver::DummyStatement.statements_exec_count / duration}"
+
+if !release
+  puts "WARNING: This should be run in release mode."
+end