Merge pull request #443 from fractaledmind/lock-wait-timeout

Add a busy_handler_timeout setter

Author: tenderlove

lib/sqlite3/database.rb

@@ -131,6 +131,7 @@ def initialize file, options = {}, zvfs = nil
       @type_translator  = make_type_translator @type_translation
       @readonly         = mode & Constants::Open::READONLY != 0
       @default_transaction_mode = options[:default_transaction_mode] || :deferred
+      @timeout_deadline = nil
 
       if block_given?
         begin
@@ -698,6 +699,25 @@ def readonly?
       @readonly
     end
 
+    # Sets a #busy_handler that releases the GVL between retries,
+    # but only retries up to the indicated number of +milliseconds+.
+    # This is an alternative to #busy_timeout, which holds the GVL
+    # while SQLite sleeps and retries.
+    def busy_handler_timeout=( milliseconds )
+      timeout_seconds = milliseconds.fdiv(1000)
+
+      busy_handler do |count|
+        now = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+        if count.zero?
+          @timeout_deadline = now + timeout_seconds
+        elsif now > @timeout_deadline
+          next false
+        else
+          sleep(0.001)
+        end
+      end
+    end
+
     # A helper class for dealing with custom functions (see #create_function,
     # #create_aggregate, and #create_aggregate_handler). It encapsulates the
     # opaque function object that represents the current invocation. It also

test/test_integration_pending.rb

@@ -79,4 +79,48 @@ def test_busy_timeout
 
     assert time.real*1000 >= 1000
   end
+
+  def test_busy_timeout_blocks_gvl
+    threads = [1, 2].map do
+      Thread.new do
+        begin
+          db = SQLite3::Database.new("test.db")
+          db.busy_timeout = 3000
+          db.transaction(:immediate) do
+            db.execute "insert into foo ( b ) values ( ? )", rand(1000).to_s
+            sleep 1
+            db.execute "insert into foo ( b ) values ( ? )", rand(1000).to_s
+          end
+        ensure
+          db.close if db
+        end
+      end
+    end
+
+    assert_raise( SQLite3::BusyException ) do
+      threads.each(&:join)
+    end
+  end
+
+  def test_busy_handler_timeout_releases_gvl
+    threads = [1, 2].map do
+      Thread.new do
+        begin
+          db = SQLite3::Database.new("test.db")
+          db.busy_handler_timeout = 3000
+          db.transaction(:immediate) do
+            db.execute "insert into foo ( b ) values ( ? )", rand(1000).to_s
+            sleep 1
+            db.execute "insert into foo ( b ) values ( ? )", rand(1000).to_s
+          end
+        ensure
+          db.close if db
+        end
+      end
+    end
+
+    assert_nothing_raised do
+      threads.each(&:join)
+    end
+  end
 end