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* Thread-safe connection pool
git-svn-id: trunk@25248 -
This commit is contained in:
michael
parent
d23a5b7c7d
commit
ae19359a7c
@ -55,11 +55,17 @@ type
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FConnectString : string;
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FIntegerDateTimes : boolean;
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FVerboseErrors : Boolean;
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FPool : TRTLCriticalSection;
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procedure CheckConnectionStatus(var conn: PPGconn);
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procedure CheckResultError(var res: PPGresult; conn:PPGconn; ErrMsg: string);
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function TranslateFldType(res : PPGresult; Tuple : integer; out Size : integer) : TFieldType;
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procedure ExecuteDirectPG(const Query : String);
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protected
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// Add connection to pool.
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procedure AddConnection(T: TPQTranConnection);
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// Release connection in pool.
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procedure ReleaseConnection(Conn: PPGConn; DoClear : Boolean);
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procedure DoInternalConnect; override;
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procedure DoInternalDisconnect; override;
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function GetHandle : pointer; override;
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@ -86,6 +92,7 @@ type
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function RowsAffected(cursor: TSQLCursor): TRowsCount; override;
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public
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constructor Create(AOwner : TComponent); override;
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destructor destroy; override;
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function GetConnectionInfo(InfoType:TConnInfoType): string; override;
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procedure CreateDB; override;
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procedure DropDB; override;
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@ -160,6 +167,13 @@ begin
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FConnOptions := FConnOptions + [sqSupportParams] + [sqEscapeRepeat] + [sqEscapeSlash];
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FieldNameQuoteChars:=DoubleQuotes;
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VerboseErrors:=True;
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InitCriticalSection(FPool);
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end;
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destructor TPQConnection.destroy;
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begin
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DoneCriticalSection(FPool);
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inherited destroy;
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end;
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procedure TPQConnection.CreateDB;
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@ -174,7 +188,7 @@ begin
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ExecuteDirectPG('DROP DATABASE ' +DatabaseName);
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end;
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procedure TPQConnection.ExecuteDirectPG(const query : string);
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procedure TPQConnection.ExecuteDirectPG(const Query: String);
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var ASQLDatabaseHandle : PPGConn;
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res : PPGresult;
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@ -207,6 +221,46 @@ begin
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{$EndIf}
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end;
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procedure TPQConnection.AddConnection(T: TPQTranConnection);
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Var
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I : Integer;
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begin
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// make connection available in pool
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EnterCriticalSection(FPool);
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try
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I:=Length(FConnectionPool);
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SetLength(FConnectionPool,I+1);
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FConnectionPool[i]:=T;
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finally
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EnterCriticalSection(FPool);
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end;
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end;
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procedure TPQConnection.ReleaseConnection(Conn: PPGConn; DoClear: Boolean);
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Var
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I : Integer;
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begin
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// make connection available in pool
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EnterCriticalSection(FPool);
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try
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for i:=0 to length(FConnectionPool)-1 do
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if (FConnectionPool[i].FPGConn=Conn) then
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begin
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FConnectionPool[i].FTranActive:=false;
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if DoClear then
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FConnectionPool[i].FPGConn:=Nil;
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break;
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end;
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finally
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EnterCriticalSection(FPool);
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end;
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end;
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function TPQConnection.GetTransactionHandle(trans : TSQLHandle): pointer;
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begin
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@ -228,13 +282,7 @@ begin
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CheckResultError(res,tr.PGConn,SErrRollbackFailed);
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PQclear(res);
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//make connection available in pool
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for i:=0 to length(FConnectionPool)-1 do
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if FConnectionPool[i].FPGConn=tr.PGConn then
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begin
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FConnectionPool[i].FTranActive:=false;
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break;
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end;
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ReleaseConnection(tr.PGCOnn,false);
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result := true;
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end;
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@ -253,12 +301,7 @@ begin
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PQclear(res);
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//make connection available in pool
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for i:=0 to length(FConnectionPool)-1 do
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if FConnectionPool[i].FPGConn=tr.PGConn then
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begin
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FConnectionPool[i].FTranActive:=false;
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break;
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end;
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ReleaseConnection(tr.PGConn,false);
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result := true;
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end;
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@ -267,35 +310,45 @@ var
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res : PPGresult;
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tr : TPQTrans;
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i : Integer;
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t : TPQTranConnection;
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begin
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result:=false;
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tr := trans as TPQTrans;
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//find an unused connection in the pool
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i:=0;
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while i<length(FConnectionPool) do
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if (FConnectionPool[i].FPGConn=nil) or not FConnectionPool[i].FTranActive then
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break
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else
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EnterCriticalSection(FPool);
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try
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while i<length(FConnectionPool) do
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begin
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T:=FConnectionPool[i];
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if (T.FPGConn=nil) or not T.FTranActive then
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break
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else
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T:=Nil;
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i:=i+1;
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if i=length(FConnectionPool) then //create a new connection
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end;
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// set to active now, so when we exit critical section,
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// it will be marked active and will not be found.
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if Assigned(T) then
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T.FTranActive:=true;
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finally
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LeaveCriticalSection(FPool);
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end;
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if (T=Nil) then
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begin
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T:=TPQTranConnection.Create;
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T.FTranActive:=True;
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AddConnection(T);
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end;
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if (T.FPGConn<>nil) then
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tr.PGConn:=T.FPGConn
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else
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begin
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tr.PGConn := PQconnectdb(pchar(FConnectString));
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CheckConnectionStatus(tr.PGConn);
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if CharSet <> '' then
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PQsetClientEncoding(tr.PGConn, pchar(CharSet));
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//store the new connection
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SetLength(FConnectionPool,i+1);
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FConnectionPool[i]:=TPQTranConnection.Create;
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FConnectionPool[i].FPGConn:=tr.PGConn;
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FConnectionPool[i].FTranActive:=true;
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end
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else //re-use existing connection
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begin
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tr.PGConn:=FConnectionPool[i].FPGConn;
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FConnectionPool[i].FTranActive:=true;
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end;
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res := PQexec(tr.PGConn, 'BEGIN');
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@ -339,7 +392,10 @@ end;
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procedure TPQConnection.DoInternalConnect;
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var ASQLDatabaseHandle : PPGConn;
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var
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ASQLDatabaseHandle : PPGConn;
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T : TPQTranConnection;
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begin
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{$IfDef LinkDynamically}
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InitialisePostgres3;
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@ -365,24 +421,28 @@ begin
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// This only works for pg>=8.0, so timestamps won't work with earlier versions of pg which are compiled with integer_datetimes on
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if PQparameterStatus<>nil then
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FIntegerDateTimes := PQparameterStatus(ASQLDatabaseHandle,'integer_datetimes') = 'on';
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SetLength(FConnectionPool,1);
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FConnectionPool[0]:=TPQTranConnection.Create;
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FConnectionPool[0].FPGConn:=ASQLDatabaseHandle;
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FConnectionPool[0].FTranActive:=false;
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T:=TPQTranConnection.Create;
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T.FPGConn:=ASQLDatabaseHandle;
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T.FTranActive:=false;
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AddConnection(T);
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end;
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procedure TPQConnection.DoInternalDisconnect;
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var i:integer;
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begin
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Inherited;
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for i:=0 to length(FConnectionPool)-1 do
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begin
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if assigned(FConnectionPool[i].FPGConn) then
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PQfinish(FConnectionPool[i].FPGConn);
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FConnectionPool[i].Free;
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end;
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Setlength(FConnectionPool,0);
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EnterCriticalSection(FPool);
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try
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for i:=0 to length(FConnectionPool)-1 do
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begin
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if assigned(FConnectionPool[i].FPGConn) then
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PQfinish(FConnectionPool[i].FPGConn);
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FConnectionPool[i].Free;
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end;
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Setlength(FConnectionPool,0);
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finally
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LeaveCriticalSection(FPool);
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end;
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{$IfDef LinkDynamically}
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ReleasePostgres3;
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{$EndIf}
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@ -396,13 +456,7 @@ begin
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begin
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sErr := PQerrorMessage(conn);
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//make connection available in pool
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for i:=0 to length(FConnectionPool)-1 do
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if FConnectionPool[i].FPGConn=conn then
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begin
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FConnectionPool[i].FPGConn:=nil;
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FConnectionPool[i].FTranActive:=false;
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break;
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end;
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ReleaseConnection(Conn,True);
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PQfinish(conn);
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DatabaseError(sErrConnectionFailed + ' (PostgreSQL: ' + sErr + ')', Self);
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end;
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@ -463,14 +517,7 @@ begin
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if assigned(conn) then
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begin
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PQFinish(conn);
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//make connection available in pool
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for i:=0 to length(FConnectionPool)-1 do
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if FConnectionPool[i].FPGConn=conn then
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begin
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FConnectionPool[i].FPGConn:=nil;
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FConnectionPool[i].FTranActive:=false;
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break;
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end;
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ReleaseConnection(Conn,True);
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end;
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raise E;
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end;
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@ -549,18 +596,18 @@ begin
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end;
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end;
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Function TPQConnection.AllocateCursorHandle : TSQLCursor;
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function TPQConnection.AllocateCursorHandle: TSQLCursor;
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begin
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result := TPQCursor.create;
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end;
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Procedure TPQConnection.DeAllocateCursorHandle(var cursor : TSQLCursor);
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procedure TPQConnection.DeAllocateCursorHandle(var cursor: TSQLCursor);
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begin
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FreeAndNil(cursor);
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end;
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Function TPQConnection.AllocateTransactionHandle : TSQLHandle;
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function TPQConnection.AllocateTransactionHandle: TSQLHandle;
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begin
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result := TPQTrans.create;
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@ -625,7 +672,7 @@ begin
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if FStatementType in [stInsert,stUpdate,stDelete, stSelect] then
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begin
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StmtName := 'prepst'+inttostr(FCursorCount);
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inc(FCursorCount);
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InterlockedIncrement(FCursorCount);
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tr := TPQTrans(aTransaction.Handle);
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// Only available for pq 8.0, so don't use it...
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// Res := pqprepare(tr,'prepst'+name+nr,pchar(buf),params.Count,pchar(''));
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