优化 连接池对象预热效率，开启每10个线程进行预热；

FreeSql/FreeUtil.cs

@@ -1,6 +1,10 @@
-using System;
+using SafeObjectPool;
+using System;
+using System.Collections.Concurrent;
+using System.Data.Common;
 using System.Diagnostics;
 using System.Threading;
+using System.Threading.Tasks;
 
 public static class FreeUtil {
 
@@ -27,4 +31,36 @@ public static class FreeUtil {
 		var guid = $"{uninxtime.ToString("x8").PadLeft(8, '0')}{__staticMachine.ToString("x8").PadLeft(8, '0').Substring(2, 6)}{__staticPid.ToString("x8").PadLeft(8, '0').Substring(6, 2)}{increment.ToString("x8").PadLeft(8, '0')}{rand.ToString("x8").PadLeft(8, '0')}";
 		return Guid.Parse(guid);
 	}
+
+	internal static void PrevReheatConnectionPool(ObjectPool<DbConnection> pool) {
+		var initTestOk = true;
+		var initStartTime = DateTime.Now;
+		var initConns = new ConcurrentBag<Object<DbConnection>>();
+
+		try {
+			var conn = pool.Get();
+			initConns.Add(conn);
+			pool.Policy.OnCheckAvailable(conn);
+		} catch {
+			initTestOk = false; //预热一次失败，后面将不进行
+		}
+		for (var a = 1; initTestOk && a < pool.Policy.PoolSize; a += 10) {
+			if (initStartTime.Subtract(DateTime.Now).TotalSeconds > 3) break; //预热耗时超过3秒，退出
+			var b = Math.Min(pool.Policy.PoolSize - a, 10); //每10个预热
+			var initTasks = new Task[b];
+			for (var c = 0; c < b; c++) {
+				initTasks[c] = Task.Run(() => {
+					try {
+						var conn = pool.Get();
+						initConns.Add(conn);
+						pool.Policy.OnCheckAvailable(conn);
+					} catch {
+						initTestOk = false;  //有失败，下一组退出预热
+					}
+				});
+			}
+			Task.WaitAll(initTasks);
+		}
+		while (initConns.TryTake(out var conn)) pool.Return(conn);
+	}
 }

FreeSql/MySql/MySqlAdo/MySqlConnectionPool.cs

@@ -69,16 +69,7 @@ namespace FreeSql.MySql {
 					_connectionString = Regex.Replace(_connectionString, pattern, "", RegexOptions.IgnoreCase);
 				}
 
-				 var initConns = new List<Object<DbConnection>>();
+				FreeUtil.PrevReheatConnectionPool(_pool);
-				for (var a = 0; a < PoolSize; a++)
-					try {
-						var conn = _pool.Get();
-						initConns.Add(conn);
-						conn.Value.Ping(true);
-					} catch {
-						break; //预热失败一次就退出
-					}
-				foreach (var conn in initConns) _pool.Return(conn);
 			}
 		}
 

FreeSql/Oracle/OracleAdo/OracleConnectionPool.cs

@@ -83,16 +83,7 @@ namespace FreeSql.Oracle {
 					_connectionString = Regex.Replace(_connectionString, pattern, "", RegexOptions.IgnoreCase);
 				}
 
-				var initConns = new List<Object<DbConnection>>();
+				FreeUtil.PrevReheatConnectionPool(_pool);
-				for (var a = 0; a < PoolSize; a++)
-					try {
-						var conn = _pool.Get();
-						initConns.Add(conn);
-						conn.Value.Ping(true);
-					} catch {
-						break; //预热失败一次就退出
-					}
-				foreach (var conn in initConns) _pool.Return(conn);
 			}
 		}
 

FreeSql/PostgreSQL/PostgreSQLAdo/PostgreSQLConnectionPool.cs

@@ -78,16 +78,7 @@ namespace FreeSql.PostgreSQL {
 					_connectionString = Regex.Replace(_connectionString, pattern, "", RegexOptions.IgnoreCase);
 				}
 
-				var initConns = new List<Object<DbConnection>>();
+				FreeUtil.PrevReheatConnectionPool(_pool);
-				for (var a = 0; a < PoolSize; a++)
-					try {
-						var conn = _pool.Get();
-						initConns.Add(conn);
-						conn.Value.Ping(true);
-					} catch {
-						break; //预热失败一次就退出
-					}
-				foreach (var conn in initConns) _pool.Return(conn);
 			}
 		}
 

FreeSql/SqlServer/SqlServerAdo/SqlServerConnectionPool.cs

@@ -73,16 +73,7 @@ namespace FreeSql.SqlServer {
 					_connectionString = Regex.Replace(_connectionString, pattern, "", RegexOptions.IgnoreCase);
 				}
 
-				var initConns = new List<Object<DbConnection>>();
+				FreeUtil.PrevReheatConnectionPool(_pool);
-				for (var a = 0; a < PoolSize; a++)
-					try {
-						var conn = _pool.Get();
-						initConns.Add(conn);
-						conn.Value.Ping(true);
-					} catch {
-						break; //预热失败一次就退出
-					}
-				foreach (var conn in initConns) _pool.Return(conn);
 			}
 		}
 

FreeSql/Sqlite/SqliteAdo/SqliteConnectionPool.cs

@@ -80,16 +80,7 @@ namespace FreeSql.Sqlite {
 					Attaches = (idx == -1 ? att[1] : att[1].Substring(0, idx)).Split(',');
 				}
 
-				var initConns = new List<Object<DbConnection>>();
+				FreeUtil.PrevReheatConnectionPool(_pool);
-				for (var a = 0; a < PoolSize; a++)
-					try {
-						var conn = _pool.Get();
-						initConns.Add(conn);
-						conn.Value.Ping(true);
-					} catch {
-						break; //预热失败一次就退出
-					}
-				foreach (var conn in initConns) _pool.Return(conn);
 			}
 		}