FireDac Pooling

1.建立FDManager的ConnectionDef。并设置此Pooling为True. 

2.建立Thread类进行多个FDConnection连接DB。 

3.本列是oracle远程数据.如下图:

Open pooling是建立FDManger中的Connection. Thread按钮是建立连接的测试。右边的空白是显示连接时间(为Ticks）

时间单位换算：

1秒=1000毫秒

1毫秒=1000微秒

1微秒=1000纳秒

1纳秒=1000皮秒

1皮秒=1000飞秒

在C#中，1Ticks = 100纳秒

 

以下为代码：

  

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, FireDAC.Stan.Intf, FireDAC.Stan.Option,
  FireDAC.Stan.Error, FireDAC.UI.Intf, FireDAC.Phys.Intf, FireDAC.Stan.Def,
  FireDAC.Phys, Vcl.Buttons, FireDAC.Comp.Client, FireDAC.Stan.Pool,
  FireDAC.Stan.Async, FireDAC.VCLUI.Wait, Data.DB, Vcl.StdCtrls,
  FireDAC.Moni.Base, FireDAC.Moni.RemoteClient,FireDAC.DApt,
  FireDAC.Phys.OracleDef, FireDAC.Phys.Oracle,System.Diagnostics;

type


  TForm1 = class(TForm)
    FDManager1: TFDManager;
    SpeedButton1: TSpeedButton;
    FDConnection1: TFDConnection;
    BitBtn1: TBitBtn;
    Memo1: TMemo;
    FDMoniRemoteClientLink1: TFDMoniRemoteClientLink;
    FDPhysOracleDriverLink1: TFDPhysOracleDriverLink;
    procedure BitBtn1Click(Sender: TObject);
    procedure SpeedButton1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

  TDBThread=class(TThread)
  private
    FForm:TForm1;
    FConn:TFDConnection;
    FQry :TFDQuery;
    procedure exePrc;
  public
    procedure Execute;override;
    constructor Create(AForm:TForm1);
    destructor Destroy;override;
  end;
var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.BitBtn1Click(Sender: TObject);
var
  i:integer;
  ATrhed:TDBThread;
  AStopWatch:TStopwatch;
 j:Int64;

begin
  for i := 0 to 4 do   //如果产生的Connection大于连接池的数量则会报错提示
  begin
     ATrhed:= TDBThread.Create(self);
  end;
 FDConnection1.ConnectionDefName :='oracle' ;
 FDConnection1.LoginPrompt := false;

//以下为不用连接池,时间就比较长
  AStopWatch := TStopwatch.StartNew;
  FDConnection1.Connected := true;
  AStopWatch.Stop;
  i:=AStopWatch.ElapsedTicks;
    self.Memo1.Lines.Add('not pooling: '+j.ToString()+' Ticks');

end;

procedure TForm1.SpeedButton1Click(Sender: TObject);
var
  conn:  IFDStanConnectionDef;
begin
  FDManager1.Close;
  conn:= self.FDManager1.ConnectionDefs.AddConnectionDef;
  conn.Name :='ora_test';
  conn.Params.DriverID :='Ora';
  conn.Params.UserName :='admin';
  conn.Params.Password :='pwd';
  conn.Params.Database := 'testdb';
  conn.Params.Pooled := True; //启用pool
  conn.Params.PoolMaximumItems := 5; //10.2.3中默认的最大池为50.一般够用
  conn.Apply;//此方法可以不用
  FDManager1.Open;//产生池
end;

{ TDBThread }

constructor TDBThread.Create(AForm: TForm1);
begin
  FreeOnTerminate := True;
  FForm := AForm;
  FConn := TFDConnection.Create(nil);
  FQry := TFDQuery.Create(nil);
  FQry.Connection := FConn;
  FConn.ConnectionDefName := AForm.FDManager1.ConnectionDefs.ConnectionDefByName('ora_test').Name;//自动调用池,相当于FDmanager.AcquireConnection方法。最好按此列调用
  inherited Create(false);;

end;

destructor TDBThread.Destroy;
begin
  FConn.Free;
  FQry.Free;
  inherited;
end;

procedure TDBThread.Execute;
begin
  FQry.Close;
  FQry.Open('select sysdate from dual');
  Synchronize(exePrc);
end;

procedure TDBThread.exePrc;
var
 AStopWatch:TStopwatch;
 i:Int64;
begin
  AStopWatch := TStopwatch.StartNew;
  FConn.Connected := True;
  AStopWatch.Stop;
  i:=AStopWatch.ElapsedTicks;
  FForm.Memo1.Lines.Add('pooling: '+i.ToString()+' Ticks');
end;

end.

 运行结果：