PostgreSQL停止时永远不会触发TFDConnection.OnRecover [英] TFDConnection.OnRecover is never fired when PostgreSQL stops

问题描述

我使用了Firedac连接恢复功能，如恢复连接（FireDAC）中所述，并且一切都可以在Delphi XE5上正常工作。

I used the Firedac connection recovery feature as described at Recovering Connection (FireDAC) and everything worked fine with Delphi XE5.

我安装了Delphi社区版本10.2、10.3和10.3.1进行迁移测试，发现数据库重新连接功能

I installed Delphi community versions 10.2, 10.3 and 10.3.1 for migration testing and found that the database reconnect feature is not working as it should.

使用场景：

• Windows 10 PRO X64 1803


• Delphi 10.2 / 10.3 / 10.3.1


• PostgreSQL 9.5.16 x64

重现该问题的步骤：

1-创建一个新的VCL应用程序；

1 - Create a new VCL application;

2-在Form1上，删除组件TFDConnection，TFDPhysPgDriverLink，TFDGUIxWaitCursor，TFDQuery和TButton；

2 - On Form1, drop the components TFDConnection, TFDPhysPgDriverLink, TFDGUIxWaitCursor, TFDQuery and TButton;

3-使用PostgreSQL和vendorlib libpq.dll的连接参数配置TFDConnection for TFDPhysPgDriverLink;

3 - Configure the TFDConnection with the connection parameters for PostgreSQL and vendorlib libpq.dll for TFDPhysPgDriverLink;

4-按照恢复连接（FireDAC）;

5-在TButton OnClick事件中放置以下内容：

5 - In the TButton OnClick event place the following:

qry1.Close;
qry1.Open ('select 1');

6-在TFDConnection的OnRecover事件中，将代码放在下面，如恢复连接（FireDAC）：

6 - In the OnRecover event of TFDConnection put the code below, as described at Recovering Connection (FireDAC):

var
  iRes: Integer;
begin
  iRes: = MessageDlg ('Connection is lost. Offline - yes, Retry - ok, Fail - Cancel', mtConfirmation, [mbYes, mbOK, mbCancel], 0);
  case iRes of
    mrYes: AAction: = faOfflineAbort;
    mrOk: AAction: = faRetry;
    mrCancel: AAction: = faFail;
  end;
// Log ('Connection is recovering');

7-运行应用程序；

7 - Run the application;

8-单击一次TButton；

8 - Click the TButton once;

9-重新启动PostgreSQL服务或禁用/重新启用网络适配器；

9 - Restart the PostgreSQL service or disable / re-enable the network adapter;

10-再次单击TButton，请注意TFDConnection组件没有触发OnRecover事件，而是显示以下错误：

10 - Click on the TButton again and note that the TFDConnection component didn't trigger the OnRecover event, instead, the following error is displayed:

[FireDAC] [Phys] [PG] [libpq]服务器意外关闭了连接
，这可能意味着服务器在处理请求之前或期间异常终止了
。

[FireDAC] [Phys] [PG] [libpq] server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request.

再次单击TButton每次都会显示另一个错误：

Clicking again on the TButton another error is displayed every time:

[FireDAC] [Phys] [PG] [libpq]没有与服务器的连接

[FireDAC] [Phys] [PG] [libpq] no connection to the server

在此先感谢您对此进行审查。

Thanks in advance for reviewing this.

此问题与我的情况相似，但适用于Delphi 10：
当PostgreSQL停止TFDConnection.Connected仍为True

This question has similarity to my case, but it was for Delphi 10: When PostgreSQL stops TFDConnection.Connected remains True

推荐答案

我根据RSP-23958向Embarcadero质量中心报告了此问题，并且对该错误进行了认可。有人叫德米特里（Dmitry）回答说，该问题将在Delphi 10.3的更新2中得到解决。

I reported this problem to Embarcadero quality central, according RSP-23958, and the bug are comproved of them. Someone called Dmitry answered that the problem will be fixed with update 2 of Delphi 10.3.

在RSP-23958中，附有一个解决该问题的修复程序，您如果您具有带有Firedac源代码的Dephi，而Delphi 10.3 Update 2没有发布，则可以使用它。

In the RSP-23958, was attached a fix patch that solve the problem and you you can use it, if you have Dephi with Firedac source code, while Delphi 10.3 update 2 not released.

解决方法如下：

Index: runtime/data/firedac/FireDAC.Phys.PGWrapper.pas
===================================================================
--- runtime/data/firedac/FireDAC.Phys.PGWrapper.pas (revision 95224)
+++ runtime/data/firedac/FireDAC.Phys.PGWrapper.pas (revision 95225)
@@ -1109,7 +1109,9 @@
      FDStrLike(sLCMessage, 'password authentication failed for user "%"') then
     eKind := ekUserPwdInvalid
   else if (Pos('connection refused', sLCMessage) <> 0) or
-          (Pos('could not connect to server', sLCMessage) <> 0) then
+          (Pos('could not connect to server', sLCMessage) <> 0) or
+          (Pos('server closed the connection unexpectedly', sLCMessage) <> 0) or
+          (Pos('no connection to the server', sLCMessage) <> 0) then
     eKind := ekServerGone
   else
     eKind := ekOther;

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