优化动态分库的demo

samples/Sample.AutoCreateIfPresent/AreaDeviceRoute.cs

@@ -18,20 +18,22 @@ namespace Sample.AutoCreateIfPresent
         private const string TABLE_NAME = "TABLE_NAME";
 
         private const string CurrentTableName = nameof(AreaDevice);
-       
-        private readonly ConcurrentDictionary<string, object?> _tails = new ConcurrentDictionary<string, object?>(StringComparer.OrdinalIgnoreCase);
-        private readonly object _lock = new object();
 
-        public AreaDeviceRoute(IVirtualDataSource virtualDataSource,  IShardingTableCreator tableCreator)
+        private readonly ConcurrentDictionary<string, object?> _tails =
+            new ConcurrentDictionary<string, object?>(StringComparer.OrdinalIgnoreCase);
+
+        private readonly object _lock = new object();
+        private readonly object _initLock = new object();
+        private bool _inited = false;
+
+        public AreaDeviceRoute(IVirtualDataSource virtualDataSource, IShardingTableCreator tableCreator)
         {
             _virtualDataSource = virtualDataSource;
             _tableCreator = tableCreator;
-            InitTails();
         }
 
         private void InitTails()
         {
-            
             using (var connection = new MySqlConnection(_virtualDataSource.DefaultConnectionString))
             {
                 connection.Open();
@@ -45,22 +47,23 @@ namespace Sample.AutoCreateIfPresent
                         if (database.Equals($"{schema}", StringComparison.OrdinalIgnoreCase))
                         {
                             var tableName = dataTable.Rows[i][TABLE_NAME]?.ToString() ?? string.Empty;
-                            if (tableName.StartsWith(CurrentTableName,StringComparison.OrdinalIgnoreCase))
+                            if (tableName.StartsWith(CurrentTableName, StringComparison.OrdinalIgnoreCase))
                             {
                                 //如果没有下划线那么需要CurrentTableName.Length有下划线就要CurrentTableName.Length+1
-                                _tails.TryAdd(tableName.Substring(CurrentTableName.Length+1), null);
+                                _tails.TryAdd(tableName.Substring(CurrentTableName.Length + 1), null);
                             }
                         }
                     }
                 }
             }
         }
-        
+
 
         public override string ShardingKeyToTail(object shardingKey)
         {
             return $"{shardingKey}";
         }
+
         /// <summary>
         /// 如果你是非mysql数据库请自行实现这个方法返回当前类在数据库已经存在的后缀
         /// 仅启动时调用
@@ -68,6 +71,18 @@ namespace Sample.AutoCreateIfPresent
         /// <returns></returns>
         public override List<string> GetTails()
         {
+            if (!_inited)
+            {
+                lock(_initLock)
+                {
+                    if (!_inited)
+                    {
+                        InitTails();
+                        _inited = true;
+                    }
+                }
+            }
+
             return _tails.Keys.ToList();
         }
 
@@ -83,17 +98,17 @@ namespace Sample.AutoCreateIfPresent
             {
                 case ShardingOperatorEnum.Equal: return tail => tail == t;
                 default:
-                    {
+                {
 #if DEBUG
-                        Console.WriteLine($"shardingOperator is not equal scan all table tail");
+                    Console.WriteLine($"shardingOperator is not equal scan all table tail");
 #endif
-                        return tail => true;
+                    return tail => true;
-                    }
+                }
             }
         }
 
         public override TableRouteUnit RouteWithValue(DataSourceRouteResult dataSourceRouteResult, object shardingKey)
-        { 
+        {
             var shardingKeyToTail = ShardingKeyToTail(shardingKey);
             if (!_tails.TryGetValue(shardingKeyToTail, out var _))
             {
@@ -101,7 +116,6 @@ namespace Sample.AutoCreateIfPresent
                 {
                     if (!_tails.TryGetValue(shardingKeyToTail, out var _))
                     {
-                       
                         try
                         {
                             _tableCreator.CreateTable<AreaDevice>(_virtualDataSource.DefaultDataSourceName,

samples/Sample.AutoCreateIfPresent/OrderByHourRoute.cs

@@ -27,12 +27,13 @@ namespace Sample.AutoCreateIfPresent
         private readonly IShardingTableCreator _shardingTableCreator;
         private readonly ConcurrentDictionary<string, object?> _tails = new ConcurrentDictionary<string, object?>(StringComparer.OrdinalIgnoreCase);
         private readonly object _lock = new object();
+        private readonly object _initLock = new object();
+        private bool _inited = false;
 
         public OrderByHourRoute(IVirtualDataSource virtualDataSource, IShardingTableCreator shardingTableCreator)
         {
             _virtualDataSource = virtualDataSource;
             _shardingTableCreator = shardingTableCreator;
-            InitTails();
         }
 
         private void InitTails()
@@ -82,6 +83,17 @@ namespace Sample.AutoCreateIfPresent
         /// <returns></returns>
         public override List<string> GetTails()
         {
+            if (!_inited)
+            {
+                lock(_initLock)
+                {
+                    if (!_inited)
+                    {
+                        InitTails();
+                        _inited = true;
+                    }
+                }
+            }
             return _tails.Keys.ToList();
         }