options cleanup

Documentation/Books/Manual/Administration/Configuration/GeneralArangod.md

@@ -302,10 +302,24 @@ The default value for this option is *false*.
 
 ### Server threads
 
-`--server.threads number`
+`--server.minimal-threads number`
+
+`--server.maximal-threads number`
 
 Specifies the *number* of threads that are spawned to handle requests.
 
+The actual number of request processing threads is adjusted dynamically at runtime
+and will float between `--server.minimal-threads` and `--server.maximal-threads`.
+
+`--server.minimal-threads` determines the minimum number of request processing
+threads the server will start and that will always be kept around. The default
+value is *2*.
+
+`--server.maximal-threads` determines the maximum number of request processing 
+threads the server is allowed to start for request handling. If that number of 
+threads is already running, arangod will not start further threads for request 
+handling. The default value is 
+
 ### Toggling server statistics
 
 `--server.statistics value`

Documentation/Books/Manual/ReleaseNotes/UpgradingChanges34.md

@@ -55,17 +55,14 @@ be strictly bounded by configuration options.
 
 The number of server threads is now configured by the following startup options:
 
-- `--server.threads`: determines the maximum number of request processing threads
-  the server will start for request handling. If that number of threads is already
-  running, arangod will not start further threads for request handling
 - `--server.minimal-threads`: determines the minimum number of request processing
   threads the server will start and always keep around
+- `--server.maximal-threads`: determines the maximum number of request processing 
+  threads the server will start for request handling. If that number of threads is 
+  already running, arangod will not start further threads for request handling
 
 The actual number of request processing threads is adjusted dynamically at runtime
-and will float between `--server.minimal-threads` and `--server.threads`.
+and will float between `--server.minimal-threads` and `--server.maximal-threads`.
-
-To avoid overloading servers, the value of `--server.threads` should not exceed the 
-server's number of hardware threads in ArangoDB 3.4.
 
 
 HTTP REST API
@@ -248,24 +245,17 @@ less V8 contexts than 3.3.
 Startup option changes
 ----------------------
 
-The arangod, the following startup options have changed:
+For arangod, the following startup options have changed:
 
-- the hidden option `--server.maximal-threads` is now obsolete.
+- the number of server threads is now configured by the following startup options:
 
-  Setting the option will have no effect. 
-  The number of server threads is now configured by the following startup options:
-
-  - `--server.threads`: determines the maximum number of request processing threads
-    the server will start
   - `--server.minimal-threads`: determines the minimum number of request processing
     threads the server will start
+  - `--server.maximal-threads`: determines the maximum number of request processing 
+    threads the server will start
 
   The actual number of request processing threads is adjusted dynamically at runtime
-  and will float between `--server.minimal-threads` and `--server.threads`. Thus the
+  and will float between `--server.minimal-threads` and `--server.maximal-threads`. 
-  value configured for `--server.threads` should not greatly exceed the server's number
-  of hardware threads.
-
-- the option `--server.maximal-queue-size` has been renamed to `--server.queue-size`.
 
 - the default value for the existing startup option `--javascript.gc-interval`
   has been increased from every 1000 to every 2000 requests, and the default value
@@ -286,6 +276,9 @@ The arangod, the following startup options have changed:
   As direct upgrades from ArangoDB 3.0 to 3.4 or from 3.1 to 3.4 are not supported,
   this option has been removed in 3.4.
 
+- the startup option `--server.session-timeout` has been obsoleted. Setting this 
+  option will not have any effect.
+
 
 Permissions
 -----------

Documentation/DocuBlocks/serverThreads.md

@@ -1,5 +0,0 @@
-@brief number of threads
-`--server.threads number`
-
-Specifies the desired *number* of threads that are spawned to handle requests.
-

arangod/GeneralServer/AuthenticationFeature.cpp

@@ -84,7 +84,7 @@ void AuthenticationFeature::collectOptions(
   options->addOldOption("no-server", "server.rest-server");
 
   options->addOption("--server.authentication",
-                     "enable or disable authentication for ALL client requests",
+                     "enable authentication for ALL client requests",
                      new BooleanParameter(&_active));
 
   options->addOption(
@@ -94,7 +94,7 @@ void AuthenticationFeature::collectOptions(
 
   options->addOption(
       "--server.local-authentication",
-      "enable or disable authentication using the local user database",
+      "enable authentication using the local user database",
       new BooleanParameter(&_localAuthentication));
 
   options->addOption(

arangod/GeneralServer/GeneralServerFeature.cpp

@@ -147,7 +147,7 @@ void GeneralServerFeature::collectOptions(
   options->addSection("frontend", "Frontend options");
 
   options->addOption("--frontend.proxy-request-check",
-                     "enable or disable proxy request checking",
+                     "enable proxy request checking",
                      new BooleanParameter(&_proxyCheck));
 
   options->addOption("--frontend.trusted-proxy",

arangod/RestServer/ServerFeature.cpp

@@ -67,9 +67,9 @@ void ServerFeature::collectOptions(std::shared_ptr<ProgramOptions> options) {
   options->addHiddenOption("--server.rest-server", "start a rest-server",
                            new BooleanParameter(&_restServer));
 
-  options->addOption("--server.session-timeout",
+  options->addObsoleteOption("--server.session-timeout",
-                     "timeout of web interface server sessions (in seconds)",
+                             "timeout of web interface server sessions (in seconds)",
-                     new DoubleParameter(&VocbaseContext::ServerSessionTtl));
+                             true);
 
   options->addSection("javascript", "Configure the Javascript engine");
 

arangod/RestServer/VocbaseContext.cpp

@@ -30,9 +30,6 @@ using namespace arangodb::rest;
 
 namespace arangodb {
 
-double VocbaseContext::ServerSessionTtl =
-    60.0 * 60.0 * 24 * 60;  // 2 month session timeout
-
 VocbaseContext::VocbaseContext(
     GeneralRequest& req,
     TRI_vocbase_t& vocbase,

arangod/RestServer/VocbaseContext.h

@@ -39,8 +39,6 @@ namespace arangodb {
 /// @brief just also stores the context
 class VocbaseContext : public arangodb::ExecContext {
  public:
-  static double ServerSessionTtl;
-
   TEST_VIRTUAL ~VocbaseContext();
 
   static VocbaseContext* create(GeneralRequest& req, TRI_vocbase_t& vocbase);

arangod/Scheduler/SchedulerFeature.cpp

@@ -63,39 +63,38 @@ SchedulerFeature::~SchedulerFeature() {}
 
 void SchedulerFeature::collectOptions(
     std::shared_ptr<options::ProgramOptions> options) {
-  options->addSection("scheduler", "Configure the I/O scheduler");
+  options->addSection("server", "Server features");
 
-  options->addOption("--server.threads", "number of threads",
+  // max / min number of threads
+  options->addOption("--server.maximal-threads", std::string("maximum number of request handling threads to run (0 = use system-specific default of ") + std::to_string(defaultNumberOfThreads()) + ")",
                      new UInt64Parameter(&_nrMaximalThreads));
+  
+  options->addHiddenOption("--server.minimal-threads",
+                           "minimum number of request handling threads to run",
+                           new UInt64Parameter(&_nrMinimalThreads));
+  
+  options->addOption("--server.maximal-queue-size", "size of the priority 2 fifo",
+                     new UInt64Parameter(&_fifo2Size));
 
   options->addHiddenOption(
-      "--server.queue-size",
+      "--server.scheduler-queue-size",
       "number of simultaneously queued requests inside the scheduler",
       new UInt64Parameter(&_queueSize));
 
   options->addHiddenOption("--server.prio1-size", "size of the priority 1 fifo",
                            new UInt64Parameter(&_fifo1Size));
 
-  options->addHiddenOption("--server.prio2-size", "size of the priority 2 fifo",
-                           new UInt64Parameter(&_fifo2Size));
-
-  options->addHiddenOption("--server.minimal-threads",
-                           "minimal number of threads",
-                           new UInt64Parameter(&_nrMinimalThreads));
-
   // obsolete options
-  options->addObsoleteOption("--server.maximal-threads",
+  options->addObsoleteOption("--server.threads", "number of threads", true);
-                             "maximal number of threads", true);
 
   // renamed options
-  options->addOldOption("scheduler.threads", "server.threads");
+  options->addOldOption("scheduler.threads", "server.maximal-threads");
-  options->addOldOption("server.maximal-queue-size", "server.queue-size");
 }
 
 void SchedulerFeature::validateOptions(
     std::shared_ptr<options::ProgramOptions>) {
   if (_nrMaximalThreads == 0) {
-    _nrMaximalThreads = TRI_numberProcessors();
+    _nrMaximalThreads = defaultNumberOfThreads();
   }
 
   if (_queueSize == 0) {
@@ -117,10 +116,10 @@ void SchedulerFeature::start() {
   LOG_TOPIC(DEBUG, arangodb::Logger::THREADS)
       << "Detected number of processors: " << N;
 
-  if (_nrMaximalThreads > 2 * N) {
+  if (_nrMaximalThreads > 8 * N) {
     LOG_TOPIC(WARN, arangodb::Logger::THREADS)
         << "--server.threads (" << _nrMaximalThreads
-        << ") is more than twice the number of cores (" << N
+        << ") is more than eight times the number of cores (" << N
         << "), this might overload the server";
   }
 
@@ -210,6 +209,17 @@ void SchedulerFeature::stop() {
 }
 
 void SchedulerFeature::unprepare() { SCHEDULER = nullptr; }
+    
+/// @brief return the default number of threads to use (upper bound)
+size_t SchedulerFeature::defaultNumberOfThreads() const {
+  // use two times the number of hardware threads as the default
+  size_t result = TRI_numberProcessors() * 2;
+  // but only if higher than 64. otherwise use a default minimum value of 64
+  if (result < 64) {
+    result = 64;
+  }
+  return result;
+}
 
 #ifdef _WIN32
 bool CtrlHandler(DWORD eventType) {

arangod/Scheduler/SchedulerFeature.h

@@ -56,7 +56,7 @@ class SchedulerFeature final : public application_features::ApplicationFeature {
   uint64_t _nrMinimalThreads = 2;
   uint64_t _nrMaximalThreads = 0;
   uint64_t _queueSize = 128;
-  uint64_t _fifo1Size = 16 * 4096;
+  uint64_t _fifo1Size = 1024 * 1024;
   uint64_t _fifo2Size = 4096;
 
  public:
@@ -65,6 +65,8 @@ class SchedulerFeature final : public application_features::ApplicationFeature {
   void buildHangupHandler();
 
  private:
+  /// @brief return the default number of threads to use (upper bound)
+  size_t defaultNumberOfThreads() const;
   void buildScheduler();
 
  private:

arangod/V8Server/FoxxQueuesFeature.cpp

@@ -45,7 +45,7 @@ void FoxxQueuesFeature::collectOptions(std::shared_ptr<ProgramOptions> options)
 
   options->addOption(
       "--foxx.queues", 
-      "enable or disable Foxx queues",
+      "enable Foxx queues",
       new BooleanParameter(&_enabled));
 
   options->addOption(

arangod/V8Server/V8DealerFeature.cpp

@@ -165,7 +165,7 @@ void V8DealerFeature::collectOptions(std::shared_ptr<ProgramOptions> options) {
   
   options->addHiddenOption(
       "--javascript.enabled",
-      "enable or disable the V8 JS engine entirely",
+      "enable the V8 JavaScript engine",
       new BooleanParameter(&_enableJS));
 }