Changeset 1134

Timestamp:

01/15/09 15:04:50 (15 years ago)

Author:

svonolfe

Message:

Further improved locking mechanism (avoid race conditions, performance) (#372)

Location:

trunk/sources/HeuristicLab.Hive.Server.ADODataAccess

Files:

• CachedDataAdapter.cs (modified) (16 diffs)
• ClientAdapter.cs (modified) (1 diff)
• DataAdapterBase.cs (modified) (7 diffs)
• JobAdapter.cs (modified) (1 diff)

trunk/sources/HeuristicLab.Hive.Server.ADODataAccess/CachedDataAdapter.cs

@@ -25 +25 @@
 using System.Text;
 using HeuristicLab.Hive.Contracts.BusinessObjects;
-using System.Runtime.CompilerServices;
 using System.Data;
+using System.Threading;
 
 namespace HeuristicLab.Hive.Server.ADODataAccess {
@@ -41 +41 @@
     private static bool cacheFilled = false;
 
+    private static ReaderWriterLock cacheLock =
+      new ReaderWriterLock();
+
     protected DataTable dataTable =
       new DataTable();
@@ -47 +50 @@
       new List<ICachedDataAdapter>();
 
-    [MethodImpl(MethodImplOptions.Synchronized)]
     protected CachedDataAdapter() {
+      cacheLock.AcquireWriterLock(Timeout.Infinite);
+
       if (!cacheFilled) {
         FillCache();
@@ -54 +58 @@
       }
 
+      cacheLock.ReleaseWriterLock();
+
       ServiceLocator.GetTransactionManager().OnUpdate +=
         new EventHandler(CachedDataAdapter_OnUpdate);
@@ -60 +66 @@
     protected virtual RowT FindSingleRow(Selector dbSelector,
       Selector cacheSelector) {
+      cacheLock.AcquireReaderLock(Timeout.Infinite);
+      
       RowT row =
          FindSingleRow(cacheSelector);
@@ -69 +77 @@
       }
 
+      cacheLock.ReleaseReaderLock();
+
       return row;
     }
@@ -74 +84 @@
     protected virtual IEnumerable<RowT> FindMultipleRows(Selector dbSelector,
         Selector cacheSelector) {
+      cacheLock.AcquireReaderLock(Timeout.Infinite);
+
       IList<RowT> result =
          new List<RowT>(cacheSelector());
@@ -85 +97 @@
         }
       }
+
+      cacheLock.ReleaseReaderLock();
 
       return result;
@@ -105 +119 @@
     protected virtual ICollection<ObjT> FindMultiple(Selector dbSelector,
       Selector cacheSelector) {
+      cacheLock.AcquireReaderLock(Timeout.Infinite);
+
       ICollection<ObjT> result =
         FindMultiple(cacheSelector);
@@ -110 +126 @@
       ICollection<ObjT> resultDb =
         FindMultiple(dbSelector);
+
+      cacheLock.ReleaseReaderLock();
 
       foreach (ObjT obj in resultDb) {
@@ -119 +137 @@
     }
 
-    [MethodImpl(MethodImplOptions.Synchronized)]
     protected abstract RowT InsertNewRowInCache(ObjT obj);
 
-    [MethodImpl(MethodImplOptions.Synchronized)]
     protected abstract void FillCache();
 
-    [MethodImpl(MethodImplOptions.Synchronized)]
     public abstract void SyncWithDb();
 
-    [MethodImpl(MethodImplOptions.Synchronized)]
     protected abstract bool PutInCache(ObjT obj);
 
     protected abstract RowT FindCachedById(long id);
 
-    [MethodImpl(MethodImplOptions.Synchronized)]
     void CachedDataAdapter_OnUpdate(object sender, EventArgs e) {
       foreach (ICachedDataAdapter parent in this.parentAdapters) {
@@ -140 +153 @@
 
       this.SyncWithDb();
-    }
-
-    [MethodImpl(MethodImplOptions.Synchronized)]
-    protected virtual void RemoveRowFromCache(RowT row) {
-      cache.Rows.Remove(row);
     }
 
@@ -167 +175 @@
     }
 
-    [MethodImpl(MethodImplOptions.Synchronized)]
+    private void AddToCache(RowT row) {
+      cacheLock.AcquireWriterLock(Timeout.Infinite);
+
+      cache.ImportRow(row);
+      row.Table.Rows.Remove(row);
+
+      cacheLock.ReleaseWriterLock();
+    }
+
+    private RowT AddToCache(ObjT obj) {
+      cacheLock.AcquireWriterLock(Timeout.Infinite);
+
+      RowT row =  InsertNewRowInCache(obj);
+
+      cacheLock.ReleaseWriterLock();
+
+      return row;
+    }
+
+    private void RemoveRowFromCache(RowT row) {
+      cacheLock.AcquireWriterLock(Timeout.Infinite);
+
+      dataTable.ImportRow(row);
+      cache.Rows.Remove(row);
+
+      cacheLock.ReleaseWriterLock();
+
+      UpdateRow(row);
+    }
+
     public override void Update(ObjT obj) {
       if (obj != null) {
@@ -175 +212 @@
         if (row == null) {
           if (PutInCache(obj)) {
-            row = InsertNewRowInCache(obj);
+            row = AddToCache(obj);
           } else {
             row = InsertNewRow(obj);
@@ -184 +221 @@
 
         obj.Id = (long)row[row.Table.PrimaryKey[0]];
+        LockRow(obj.Id);
 
         ConvertObj(obj, row);
@@ -191 +229 @@
 
         if (IsCached(row) &&
-            !PutInCache(obj)) {
-          //remove from cache
-          dataTable.ImportRow(row);
+            !PutInCache(obj)) {          
           RemoveRowFromCache(row);
-
-          UpdateRow(row);
         } else if (!IsCached(row) &&
           PutInCache(obj)) {
-          //add to cache
-          cache.ImportRow(row);
-          row.Table.Rows.Remove(row);
-        } 
+          AddToCache(row);
+        }
+
+        UnlockRow(obj.Id);
       }
     }

trunk/sources/HeuristicLab.Hive.Server.ADODataAccess/ClientAdapter.cs

@@ -176 +176 @@
     protected override dsHiveServer.ClientRow
       InsertNewRowInCache(ClientInfo client) {
-      dsHiveServer.ClientRow row = data.NewClientRow();
+      dsHiveServer.ClientRow row = cache.NewClientRow();
       row.ResourceId = client.Id;
       cache.AddClientRow(row);

trunk/sources/HeuristicLab.Hive.Server.ADODataAccess/DataAdapterBase.cs

@@ -26 +26 @@
 using System.Text;
 using HeuristicLab.Hive.Contracts.BusinessObjects;
-using System.Runtime.CompilerServices;
+using System.Threading;
 
 namespace HeuristicLab.Hive.Server.ADODataAccess {
@@ -33 +33 @@
     where RowT : System.Data.DataRow
     where ObjT : IHiveObject, new() {
+
+    private static Mutex lockersMutex =
+      new Mutex();
+
+    private static IDictionary<long, Mutex> lockers =
+      new Dictionary<long, Mutex>();
+
+    private static IDictionary<long, int> lockCount =
+      new Dictionary<long, int>();
+
+    protected void LockRow(long id) {
+      Mutex rowLock = null;
+
+      /////begin critical section////
+      lockersMutex.WaitOne();
+
+      if (!lockers.ContainsKey(id)) {
+        lockers[id] = new Mutex();
+        lockCount[id] = 0;
+      }
+      rowLock = lockers[id];
+      lockCount[id]++;
+      
+      lockersMutex.ReleaseMutex();
+      /////end critical section////
+
+      rowLock.WaitOne();
+    }
+
+    protected void UnlockRow(long id) {
+      Mutex rowLock = lockers[id];
+      rowLock.ReleaseMutex();
+
+      /////begin critical section////
+      lockersMutex.WaitOne();
+
+      lockCount[id]--;
+      if (lockCount[id] == 0)
+        lockers.Remove(id);
+
+      lockersMutex.ReleaseMutex();
+      /////end critical section////
+    }
+    
     protected AdapterT Adapter {
       get {
@@ -44 +88 @@
     protected abstract ObjT ConvertRow(RowT row, ObjT obj);
 
-    [MethodImpl(MethodImplOptions.Synchronized)]
     protected abstract RowT InsertNewRow(ObjT obj);
 
-    [MethodImpl(MethodImplOptions.Synchronized)]
     protected abstract void UpdateRow(RowT row);
 
@@ -119 +161 @@
     }
 
-    [MethodImpl(MethodImplOptions.Synchronized)]
     public virtual void Update(ObjT obj) {
       if (obj != null) {
@@ -127 +168 @@
         if (row == null) {
           row = InsertNewRow(obj);
+          UpdateRow(row);
         }
 
+        obj.Id = (long)row[row.Table.PrimaryKey[0]];
+        LockRow(obj.Id);
+
         ConvertObj(obj, row);
-
         UpdateRow(row);
 
-        obj.Id = (long)row[row.Table.PrimaryKey[0]];
+        UnlockRow(obj.Id);
       }
     }
@@ -149 +193 @@
     }
 
-    [MethodImpl(MethodImplOptions.Synchronized)]
     public virtual bool Delete(ObjT obj) {
+      bool success = false;
+      
       if (obj != null) {
+        LockRow(obj.Id);
+
         RowT row =
           GetRowById(obj.Id);
@@ -159 +206 @@
           UpdateRow(row);
 
-          return true;
+          success = true;
         }
-      }
-
-      return false;
+
+        UnlockRow(obj.Id);
+      }
+
+      return success;
     }
   }

trunk/sources/HeuristicLab.Hive.Server.ADODataAccess/JobAdapter.cs

@@ -160 +160 @@
     protected override dsHiveServer.JobRow 
       InsertNewRowInCache(Job job) {
-      dsHiveServer.JobRow row = data.NewJobRow();
+      dsHiveServer.JobRow row = cache.NewJobRow();
       cache.AddJobRow(row);