CommandProcessors: Initial queue sizes based on batch size

Author: alex-kulakov

Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/BatchingCommandProcessor.cs

@@ -15,7 +15,7 @@ namespace Xtensive.Orm.Providers
   internal sealed class BatchingCommandProcessor : CommandProcessor, ISqlTaskProcessor
   {
     private readonly int batchSize;
-    private Queue<SqlTask> tasks = new Queue<SqlTask>();
+    private Queue<SqlTask> tasks;
 
     void ISqlTaskProcessor.ProcessTask(SqlLoadTask task, CommandProcessorContext context)
     {
@@ -290,7 +290,7 @@ private void PutTasksForExecution(CommandProcessorContext context)
       }
       else {
         context.ProcessingTasks = tasks;
-        tasks = new Queue<SqlTask>();
+        tasks = new Queue<SqlTask>(batchSize);
       }
     }
 
@@ -328,6 +328,7 @@ public BatchingCommandProcessor(CommandFactory factory, int batchSize, int maxQu
     {
       ArgumentValidator.EnsureArgumentIsGreaterThan(batchSize, 1, nameof(batchSize));
       this.batchSize = batchSize;
+      this.tasks = new Queue<SqlTask>(batchSize);
     }
   }
 }

Orm/Xtensive.Orm/Orm/Providers/CommandProcessing/SimpleCommandProcessor.cs

@@ -14,7 +14,11 @@ namespace Xtensive.Orm.Providers
 {
   internal sealed class SimpleCommandProcessor : CommandProcessor, ISqlTaskProcessor
   {
-    private Queue<SqlTask> tasks = new();
+    // equals to default batch size from SessionConfiguration
+    // hard to choose particular value so let it be some known number :)
+    private const int DefaultTaskQueueCapacity = 25;
+
+    private Queue<SqlTask> tasks = new(DefaultTaskQueueCapacity);
 
     void ISqlTaskProcessor.ProcessTask(SqlLoadTask task, CommandProcessorContext context)
     {
@@ -52,7 +56,7 @@ void ISqlTaskProcessor.ProcessTask(SqlPersistTask task, CommandProcessorContext
     public override void ExecuteTasks(CommandProcessorContext context)
     {
       context.ProcessingTasks = tasks;
-      tasks = new Queue<SqlTask>();
+      tasks = new Queue<SqlTask>(DefaultTaskQueueCapacity);
 
       while (context.ProcessingTasks.Count > 0) {
         AllocateCommand(context);
@@ -80,7 +84,7 @@ public override void ExecuteTasks(CommandProcessorContext context)
     public override async Task ExecuteTasksAsync(CommandProcessorContext context, CancellationToken token)
     {
       context.ProcessingTasks = tasks;
-      tasks = new Queue<SqlTask>();
+      tasks = new Queue<SqlTask>(DefaultTaskQueueCapacity);
 
       while (context.ProcessingTasks.Count > 0) {
         AllocateCommand(context);