I created a vcl component which uses firedac to access a PostgreSQL database. This works fine, except for query tracing, which I cannot get to work.
In component constructor, I create connection object, set params etc. In the uses clause, I added FireDAC.Phys.PG and FireDAC.Moni.Base, FireDAC.Moni.FlatFile.
Following the embarcadero docs, the TFDMoniFlatFileClientLink is created before the TFDConnection, and tracing is set to true for both the FDTracer and the FDConnection.ConnectionIntf.
unit My.Database;
interface
uses
System.SysUtils, System.Classes, FireDAC.Comp.UI, FireDAC.Comp.Client, FireDAC.Phys.PG,
FireDAC.Moni.Base, FireDAC.Moni.FlatFile;
type
TMyDatabase = class(TComponent)
private
{ Private declarations }
FDTracer: TFDMoniFlatFileClientLink;
FDConnection: TFDConnection;
FConnectionString: string;
public
{ Public declarations }
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
function IsConnected: Boolean;
property ConnectionString: stringread FConnectionString write FConnectionString;
function OpenConnection: Boolean;
function GetAsDataset(ASQL: string): TFDQuery;
end;
implementation
uses
FireDAC.Stan.Intf, FireDAC.Stan.Option, FireDAC.Stan.Error, FireDAC.Stan.Def, FireDAC.Stan.Async,
FireDAC.VCLUI.Login, FireDAC.VCLUI.Wait;
constructor TMyDatabase.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
FDTracer := TFDMoniFlatFileClientLink.Create(Self);
FDConnection := TFDConnection.Create(Self);
FDTracer.tracing := True;
with FDConnection do
begin
DriverName := 'PG';
LoginPrompt := False;
//params for PostgreSQL
with Params do
begin
Add('Port=5432');
Add('LoginTimeout=2');
Add('Pooled=False');
Add('OidAsBlob=No');
Add('UnknownFormat=BYTEA');
Add('ExtendedMetadata=True');
end;
end;
FDConnection.ConnectionIntf.Tracing := True;
end;
function TMyDatabase.IsConnected: Boolean;
begin
Result := FDConnection.Connected;
end;
function TMyDatabase.OpenConnection: Boolean;
begin
with FDConnection do
try
ConnectionString := FConnectionString;
if not Connected then
begin
Open;
end;
finally
Result := Connected;
end;
end;
function TMyDatabase.GetAsDataset(ASQL: string): TFDQuery;
begin
Result := TFDQuery.Create(Self);
with Result do
begin
Connection := FDConnection;
end;
Result.Open(ASQL);
end;
When I connect to a database and execute a query via GetAsDataSet, the trace file only logs the starting/stopping of the FireDac connection, but not the execution of the query. If I put the TFDConnection and TFDMoniFlatFileClientLink components on a form or datamodule, query execution is traced as expected.
Anyone who knows how to trace the execution of a query with a connection object that is created dynamically from a component?
Best regards, Ronald
I tried to reproduce your problem in a simple FireDAC testbed of mine, by adding
a TFDMoniFlatFileClientLink to it and got a similar result, i.e. the trace file
contained entries saying that it had been started and stopped, but nothing in between.
Looking at http://docwiki.embarcadero.com/CodeExamples/Tokyo/en/FireDAC.MoniLayerClients_Sample
I seemed to be missing a small but vital step, namely to set the MonitorBy parameter of
my FDConnection to 'FlatFile', to match the TFDMoniFlatFileClientLink
So, just before opening the connection in my code, I added the first line below
FDConnection1.Params.MonitorBy := mbFlatFile;
FDConnection1.Connected := True;
and the trace then ran fine.
Partial trace extract
--- new start of FireDAC Trace ---
4361928750001 19:48:07.092 -=#!!! FireDAC Tracer started !!!#=-
4361928750001 19:48:07.094 TFDPhysMSSQLConnection TFDPhysMSSQLConnecti . CreateConnection [ConnectionDef=""]
4361928750001 19:48:07.094 TFDPhysMSSQLConnection TFDPhysMSSQLConnecti . CreateTransaction [ConnectionDef=""]
4361928750001 19:48:07.094 TFDPhysMSSQLConnection FDConnection1 >> Open [ConnectionDef=""]
4361928750001 19:48:07.094 TFDConnectionDef $0100C390 >> Definition [Name=""]
4361928750001 19:48:07.094 TFDConnectionDef $0100C390 . Server=MAT430\ss2014
4361928750001 19:48:07.094 TFDConnectionDef $0100C390 . User_Name=sa
4361928750001 19:48:07.094 TFDConnectionDef $0100C390 . Password=*****
4361928750001 19:48:07.094 TFDConnectionDef $0100C390 . Database=MAtest
4361928750001 19:48:07.094 TFDConnectionDef $0100C390 . OSAuthent=No
4361928750001 19:48:07.094 TFDConnectionDef $0100C390 . DriverID=MSSQL
4361928750001 19:48:07.094 TFDConnectionDef $0100C390 . MonitorBy=FlatFile
4361928750001 19:48:07.094 TFDConnectionDef $0100C390 << Definition [Name=""]
4361928750001 19:48:07.094 TFDPhysMSSQLConnection FDConnection1 >> FireDAC info
4361928750001 19:48:07.094 TFDPhysMSSQLConnection FDConnection1 . Tool=RAD Studio 10.2
4361928750001 19:48:07.094 TFDPhysMSSQLConnection FDConnection1 . FireDAC=16.0.0 (Build 88974)
4361928750001 19:48:07.094 TFDPhysMSSQLConnection FDConnection1 . Platform=Windows 32 bit
4361928750001 19:48:07.094 TFDPhysMSSQLConnection FDConnection1 . Defines=FireDAC_NOLOCALE_META;FireDAC_MONITOR
4361928750001 19:48:07.094 TFDPhysMSSQLConnection FDConnection1 << FireDAC info
4361931710001 19:48:07.390 TFDPhysMSSQLConnection FDConnection1 . SQLDriverConnect [szConnStr="DRIVER=SQL Server Native Client 11.0;UID=sa;PWD=*******;Server=MAT430\ss2014;Database=MAtest;Trusted_Connection=No;MARS_Connection=yes"]
4361931710001 19:48:07.392 TFDPhysMSSQLDriver MSSQL . ENTER SQLDriverConnectW
HDBC 0x01044B18
HWND 0x00000000
WCHAR * 0x61942440 [ -3] "******\ 0"
SWORD -3
WCHAR * 0x61942440
SWORD -3
SWORD * 0x00000000
UWORD 0 <SQL_DRIVER_NOPROMPT>
4361935310001 19:48:07.756 TFDPhysMSSQLDriver MSSQL . EXIT SQLDriverConnectW with return code 1 (SQL_SUCCESS_WITH_INFO)
HDBC 0x01044B18
HWND 0x00000000
WCHAR * 0x61942440 [ -3] "******\ 0"
SWORD -3
WCHAR * 0x61942440 <Invalid buffer length!> [-3]
SWORD -3
SWORD * 0x00000000
UWORD 0 <SQL_DRIVER_NOPROMPT>
DIAG [01000] [Microsoft][SQL Server Native Client 11.0][SQL Server]Changed database context to 'MAtest'. (5701)
DIAG [01000] [Microsoft][SQL Server Native Client 11.0][SQL Server]Changed language setting to us_english. (5703)
4361935310001 19:48:07.758 TFDPhysMSSQLDriver MSSQL . ENTER SQLGetDiagRecW
SQLSMALLINT 2 <SQL_HANDLE_DBC>
SQLHANDLE 0x01044B18
SQLSMALLINT 1
SQLWCHAR * 0x00FCB5CC
SQLINTEGER * 0x0019F840
SQLWCHAR * 0x0019D83A
SQLSMALLINT 4096
SQLSMALLINT * 0x0019F846
followed by the remainder of the kitchen sink.