Only force prim persistence before delete if the prim is the result of an unpersisted delink

This considerably improves delete performance for objects with large linksets

OpenSim/Region/Framework/Scenes/Scene.cs

@@ -1997,7 +1997,7 @@ namespace OpenSim.Region.Framework.Scenes
         /// <param name="group">Object Id</param>
         /// <param name="silent">Suppress broadcasting changes to other clients.</param>
         public void DeleteSceneObject(SceneObjectGroup group, bool silent)
-        {
+        {            
 //            m_log.DebugFormat("[SCENE]: Deleting scene object {0} {1}", group.Name, group.UUID);
             
             //SceneObjectPart rootPart = group.GetChildPart(group.UUID);
@@ -2038,7 +2038,7 @@ namespace OpenSim.Region.Framework.Scenes
 
             group.DeleteGroupFromScene(silent);
 
-//            m_log.DebugFormat("[SCENE]: Exit DeleteSceneObject() for {0} {1}", group.Name, group.UUID);
+//            m_log.DebugFormat("[SCENE]: Exit DeleteSceneObject() for {0} {1}", group.Name, group.UUID);            
         }
 
         /// <summary>
@@ -2057,9 +2057,12 @@ namespace OpenSim.Region.Framework.Scenes
                     // Force a database update so that the scene object group ID is accurate.  It's possible that the
                     // group has recently been delinked from another group but that this change has not been persisted
                     // to the DB.
-                    ForceSceneObjectBackup(so);
+                    // This is an expensive thing to do so only do it if absolutely necessary.
+                    if (so.HasGroupChangedDueToDelink)
+                        ForceSceneObjectBackup(so);                
+                    
                     so.DetachFromBackup();
-                    SimulationDataService.RemoveObject(so.UUID, m_regInfo.RegionID);
+                    SimulationDataService.RemoveObject(so.UUID, m_regInfo.RegionID);                                        
                 }
                                     
                 // We need to keep track of this state in case this group is still queued for further backup.

OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs

@@ -119,10 +119,19 @@ namespace OpenSim.Region.Framework.Scenes
                         timeFirstChanged = DateTime.Now.Ticks;
                 }
                 m_hasGroupChanged = value;
+                
+//                m_log.DebugFormat(
+//                    "[SCENE OBJECT GROUP]: HasGroupChanged set to {0} for {1} {2}", m_hasGroupChanged, Name, LocalId);
             }
 
             get { return m_hasGroupChanged; }
         }
+        
+        /// <summary>
+        /// Has the group changed due to an unlink operation?  We record this in order to optimize deletion, since
+        /// an unlinked group currently has to be persisted to the database before we can perform an unlink operation.
+        /// </summary>
+        public bool HasGroupChangedDueToDelink { get; private set; }
 
         private bool isTimeToPersist()
         {
@@ -1330,6 +1339,7 @@ namespace OpenSim.Region.Framework.Scenes
                         backup_group.RootPart.AngularVelocity = RootPart.AngularVelocity;
                         backup_group.RootPart.ParticleSystem = RootPart.ParticleSystem;
                         HasGroupChanged = false;
+                        HasGroupChangedDueToDelink = false;
 
                         m_scene.EventManager.TriggerOnSceneObjectPreSave(backup_group, this);
                         datastore.StoreObject(backup_group, m_scene.RegionInfo.RegionID);
@@ -2208,8 +2218,9 @@ namespace OpenSim.Region.Framework.Scenes
 
             linkPart.Rezzed = RootPart.Rezzed;
 
-            //HasGroupChanged = true;
+            // When we delete a group, we currently have to force persist to the database if the object id has changed
-            //ScheduleGroupForFullUpdate();
+            // (since delete works by deleting all rows which have a given object id)
+            objectGroup.HasGroupChangedDueToDelink = true;
 
             return objectGroup;
         }

OpenSim/Region/Framework/Scenes/Tests/SceneObjectLinkingTests.cs

@@ -121,13 +121,14 @@ namespace OpenSim.Region.Framework.Scenes.Tests
                 "Not exactly sure what this is asserting...");
 
             // Delink part 2
-            grp1.DelinkFromGroup(part2.LocalId);
+            SceneObjectGroup grp3 = grp1.DelinkFromGroup(part2.LocalId);
 
             if (debugtest)
                 m_log.Debug("Group2: Prim2: OffsetPosition:" + part2.AbsolutePosition + ", OffsetRotation:" + part2.RotationOffset);
 
             Assert.That(grp1.Parts.Length, Is.EqualTo(1), "Group 1 still contained part2 after delink.");
             Assert.That(part2.AbsolutePosition == Vector3.Zero, "The absolute position should be zero");
+            Assert.That(grp3.HasGroupChangedDueToDelink, Is.True);
         }
 
         [Test]
@@ -325,7 +326,7 @@ namespace OpenSim.Region.Framework.Scenes.Tests
 
             SceneObjectGroup sog = new SceneObjectGroup(rootPart);
             sog.AddPart(linkPart);
-            scene.AddNewSceneObject(sog, true);
+            scene.AddNewSceneObject(sog, true);            
             
             // In a test, we have to crank the backup handle manually.  Normally this would be done by the timer invoked
             // scene backup thread.
@@ -333,7 +334,10 @@ namespace OpenSim.Region.Framework.Scenes.Tests
                         
             // These changes should occur immediately without waiting for a backup pass
             SceneObjectGroup groupToDelete = sog.DelinkFromGroup(linkPart, false);
+            
+            Assert.That(groupToDelete.HasGroupChangedDueToDelink, Is.True);
             scene.DeleteSceneObject(groupToDelete, false);
+            Assert.That(groupToDelete.HasGroupChangedDueToDelink, Is.False);
             
             List<SceneObjectGroup> storedObjects = scene.SimulationDataService.LoadObjects(scene.RegionInfo.RegionID);
             

bin/OpenSim.exe.config

@@ -13,6 +13,8 @@
     <appender name="Console" type="OpenSim.Framework.Console.OpenSimAppender, OpenSim.Framework.Console">
       <layout type="log4net.Layout.PatternLayout">
         <conversionPattern value="%date{HH:mm:ss} - %message" />
+        <!-- console log with milliseconds.  Useful for debugging -->
+        <!-- <conversionPattern value="%date{HH:mm:ss.fff} - %message" /> -->
       </layout>
     </appender>