fbintf/client/FBStatement.pas

(*
 *  Firebird Interface (fbintf). The fbintf components provide a set of
 *  Pascal language bindings for the Firebird API. Although predominantly
 *  a new development they include source code taken from IBX and may be
 *  considered a derived product. This software thus also includes the copyright
 *  notice and license conditions from IBX.
 *
 *  Except for those parts dervied from IBX, contents of this file are subject
 *  to the Initial Developer's Public License Version 1.0 (the "License"); you
 *  may not use this file except in compliance with the License. You may obtain a
 *  copy of the License here:
 *
 *    http://www.firebirdsql.org/index.php?op=doc&id=idpl
 *
 *  Software distributed under the License is distributed on an "AS
 *  IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 *  implied. See the License for the specific language governing rights
 *  and limitations under the License.
 *
 *  The Initial Developer of the Original Code is Tony Whyman.
 *
 *  The Original Code is (C) 2016 Tony Whyman, MWA Software
 *  (http://www.mwasoftware.co.uk).
 *
 *  All Rights Reserved.
 *
 *  Contributor(s): ______________________________________.
 *
*)
unit FBStatement;
{$IFDEF MSWINDOWS} 
{$DEFINE WINDOWS} 
{$ENDIF}

{$IFDEF FPC}
{$mode delphi}
{$codepage UTF8}
{$interfaces COM}
{$ENDIF}

interface

uses
  Classes, SysUtils,  IB,  FBClientAPI, FBSQLData, FBOutputBlock, FBActivityMonitor,
  FBTransaction;

type
  TPerfStatistics = array[psCurrentMemory..psFetches] of Int64;

  { TFBStatement }

  TFBStatement = class(TActivityReporter)
  private
    FAttachmentIntf: IAttachment;
  protected
    FTransactionIntf: ITransaction;
    FExecTransactionIntf: ITransaction;
    FSQLStatementType: TIBSQLStatementTypes;         { Select, update, delete, insert, create, alter, etc...}
    FSQLDialect: integer;
    FOpen: boolean;
    FPrepared: boolean;
    FPrepareSeqNo: integer; {used to check for out of date references from interfaces}
    FSQL: AnsiString;
    FProcessedSQL: AnsiString;
    FHasParamNames: boolean;
    FBOF: boolean;
    FEOF: boolean;
    FSingleResults: boolean;
    FGenerateParamNames: boolean;
    FChangeSeqNo: integer;
    FCollectStatistics: boolean;
    FStatisticsAvailable: boolean;
    FBeforeStats: TPerfStatistics;
    FAfterStats: TPerfStatistics;
    procedure CheckHandle; virtual; abstract;
    procedure CheckTransaction(aTransaction: ITransaction);
    procedure GetDsqlInfo(info_request: byte; buffer: ISQLInfoResults); overload; virtual; abstract;
    procedure InternalPrepare;  virtual; abstract;
    function InternalExecute(aTransaction: ITransaction): IResults;  virtual; abstract;
    function InternalOpenCursor(aTransaction: ITransaction): IResultSet;   virtual; abstract;
    procedure FreeHandle;  virtual; abstract;
    procedure InternalClose(Force: boolean); virtual; abstract;
    function TimeStampToMSecs(const TimeStamp: TTimeStamp): Int64;
  public
    constructor Create(Attachment: IAttachment; Transaction: ITransaction;
      sql: AnsiString; SQLDialect: integer);
    constructor CreateWithParameterNames(Attachment: IAttachment; Transaction: ITransaction;
      sql: AnsiString;  SQLDialect: integer; GenerateParamNames: boolean =false);
    destructor Destroy; override;
    procedure Close;
    procedure TransactionEnding(aTransaction: ITransaction; Force: boolean);
    property SQLDialect: integer read FSQLDialect;

  public
    function GetSQLParams: ISQLParams; virtual; abstract;
    function GetMetaData: IMetaData;  virtual; abstract;
    function GetRowsAffected(var SelectCount, InsertCount, UpdateCount,
      DeleteCount: integer): boolean;
    function GetSQLStatementType: TIBSQLStatementTypes;
    function GetSQLText: AnsiString;
    function GetSQLDialect: integer;

    {GetDSQLInfo only supports isc_info_sql_stmt_type, isc_info_sql_get_plan, isc_info_sql_records}
    procedure Prepare(aTransaction: ITransaction=nil); virtual;
    function Execute(aTransaction: ITransaction=nil): IResults;
    function OpenCursor(aTransaction: ITransaction=nil): IResultSet;
    function CreateBlob(paramName: AnsiString): IBlob; overload;
    function CreateBlob(index: integer): IBlob; overload;
    function CreateBlob(column: TColumnMetaData): IBlob; overload; virtual; abstract;
    function CreateArray(paramName: AnsiString): IArray; overload;
    function CreateArray(index: integer): IArray;  overload;
    function CreateArray(column: TColumnMetaData): IArray; overload; virtual; abstract;
    function GetAttachment: IAttachment;
    function GetTransaction: ITransaction;
    function GetDSQLInfo(Request: byte): ISQLInfoResults; overload;
    procedure SetRetainInterfaces(aValue: boolean); virtual;
    procedure EnableStatistics(aValue: boolean);
    function GetPerfStatistics(var stats: TPerfCounters): boolean;
    property ChangeSeqNo: integer read FChangeSeqNo;
    property SQLParams: ISQLParams read GetSQLParams;
    property SQLStatementType: TIBSQLStatementTypes read GetSQLStatementType;
end;

implementation

uses FBMessages;

{ TFBStatement }

procedure TFBStatement.CheckTransaction(aTransaction: ITransaction);
begin
  if (aTransaction = nil) then
    IBError(ibxeTransactionNotAssigned,[]);

  if not aTransaction.InTransaction then
    IBError(ibxeNotInTransaction,[]);
end;

function TFBStatement.TimeStampToMSecs(const TimeStamp: TTimeStamp): Int64;
begin
  Result := TimeStamp.Time + Int64(timestamp.date)*msecsperday;
end;

constructor TFBStatement.Create(Attachment: IAttachment;
  Transaction: ITransaction; sql: AnsiString; SQLDialect: integer);
begin
  inherited Create(Transaction as TFBTransaction,2);
  FAttachmentIntf := Attachment;
  FTransactionIntf := Transaction;
  FSQLDialect := SQLDialect;
  FSQL := sql;
end;

constructor TFBStatement.CreateWithParameterNames(Attachment: IAttachment;
  Transaction: ITransaction; sql: AnsiString; SQLDialect: integer;
  GenerateParamNames: boolean);
begin
  FHasParamNames := true;
  FGenerateParamNames := GenerateParamNames;
  Create(Attachment,Transaction,sql,SQLDialect);
end;

destructor TFBStatement.Destroy;
begin
  Close;
  FreeHandle;
  inherited Destroy;
end;

procedure TFBStatement.Close;
begin
  InternalClose(false);
end;

procedure TFBStatement.TransactionEnding(aTransaction: ITransaction;
  Force: boolean);
begin
  if FOpen and (FExecTransactionIntf = aTransaction) then
    InternalClose(Force);

  if FTransactionIntf = aTransaction then
  begin
    FreeHandle;
    FPrepared := false;
  end;
end;

function TFBStatement.GetRowsAffected(var SelectCount, InsertCount,
  UpdateCount, DeleteCount: integer): boolean;
var
  RB: ISQLInfoResults;
  i, j: integer;
begin
  InsertCount := 0;
  UpdateCount := 0;
  DeleteCount := 0;
  Result := FPrepared;
  if not Result then Exit;

  RB := GetDsqlInfo(isc_info_sql_records);

  for i := 0 to RB.Count - 1 do
  with RB[i] do
  case getItemType of
  isc_info_sql_records:
    for j := 0 to Count -1 do
    with Items[j] do
    case getItemType of
    isc_info_req_select_count:
      SelectCount := GetAsInteger;
    isc_info_req_insert_count:
      InsertCount := GetAsInteger;
    isc_info_req_update_count:
      UpdateCount := GetAsInteger;
    isc_info_req_delete_count:
      DeleteCount := GetAsInteger;
    end;
  end;
end;

function TFBStatement.GetSQLStatementType: TIBSQLStatementTypes;
begin
  Result := FSQLStatementType;
end;

function TFBStatement.GetSQLText: AnsiString;
begin
  Result := FSQL;
end;

function TFBStatement.GetSQLDialect: integer;
begin
  Result := FSQLDialect;
end;

procedure TFBStatement.Prepare(aTransaction: ITransaction);
begin
  if FPrepared then FreeHandle;
  if aTransaction <> nil then
  begin
    RemoveMonitor(FTransactionIntf as TFBTransaction);
    FTransactionIntf := aTransaction;
    AddMonitor(FTransactionIntf as TFBTransaction);
  end;
  InternalPrepare;
end;

function TFBStatement.Execute(aTransaction: ITransaction): IResults;
begin
  if aTransaction = nil then
    Result :=  InternalExecute(FTransactionIntf)
  else
    Result := InternalExecute(aTransaction);
end;

function TFBStatement.OpenCursor(aTransaction: ITransaction): IResultSet;
begin
  Close;
  if aTransaction = nil then
    Result := InternalOpenCursor(FTransactionIntf)
  else
    Result := InternalOpenCursor(aTransaction);
end;

function TFBStatement.CreateBlob(paramName: AnsiString): IBlob;
var column: TColumnMetaData;
begin
  InternalPrepare;
  column := SQLParams.ByName(paramName) as TSQLParam;
  if column = nil then
    IBError(ibxeFieldNotFound,[paramName]);
  Result := CreateBlob(column);
end;

function TFBStatement.CreateBlob(index: integer): IBlob;
begin
  InternalPrepare;
  Result := CreateBlob(SQLParams[index] as TSQLParam);
end;

function TFBStatement.CreateArray(paramName: AnsiString): IArray;
var column: TColumnMetaData;
begin
  InternalPrepare;
  column := SQLParams.ByName(paramName) as TSQLParam;
  if column = nil then
    IBError(ibxeFieldNotFound,[paramName]);
  Result := CreateArray(column);
end;

function TFBStatement.CreateArray(index: integer): IArray;
begin
  InternalPrepare;
  Result := CreateArray(SQLParams[index] as TSQLParam);
end;

function TFBStatement.GetAttachment: IAttachment;
begin
  Result := FAttachmentIntf;
end;

function TFBStatement.GetTransaction: ITransaction;
begin
  Result := FTransactionIntf
end;

function TFBStatement.GetDSQLInfo(Request: byte): ISQLInfoResults;
begin
  Result := TSQLInfoResultsBuffer.Create;
  GetDsqlInfo(Request,Result);
end;

procedure TFBStatement.SetRetainInterfaces(aValue: boolean);
begin
  RetainInterfaces := aValue;
end;

procedure TFBStatement.EnableStatistics(aValue: boolean);
begin
  if FCollectStatistics <> aValue then
  begin
    FCollectStatistics := aValue;
    FStatisticsAvailable := false;
  end;
end;

function TFBStatement.GetPerfStatistics(var stats: TPerfCounters): boolean;
begin
  Result := FStatisticsAvailable;
  if Result then
  begin
    stats[psCurrentMemory] := FAfterStats[psCurrentMemory];
    stats[psDeltaMemory] := FAfterStats[psCurrentMemory] - FBeforeStats[psCurrentMemory];
    stats[psMaxMemory] := FAfterStats[psMaxMemory];
    stats[psRealTime] :=  FAfterStats[psRealTime] - FBeforeStats[psRealTime];
    stats[psUserTime] :=  FAfterStats[psUserTime] - FBeforeStats[psUserTime];
    stats[psReads] := FAfterStats[psReads] - FBeforeStats[psReads];
    stats[psWrites] := FAfterStats[psWrites] - FBeforeStats[psWrites];
    stats[psFetches] := FAfterStats[psFetches] - FBeforeStats[psFetches];
    stats[psBuffers] :=  FAfterStats[psBuffers];
  end;
end;

end.

Revision:	209
Committed:	Wed Mar 14 12:48:51 2018 UTC (6 years, 9 months ago) by tony
Content type:	text/x-pascal
Original Path:	*ibx/trunk/fbintf/client/FBStatement.pas*
File size:	10576 byte(s)
Log Message:	Fixes Merged
#	Content
1	(*
2	* Firebird Interface (fbintf). The fbintf components provide a set of
3	* Pascal language bindings for the Firebird API. Although predominantly
4	* a new development they include source code taken from IBX and may be
5	* considered a derived product. This software thus also includes the copyright
6	* notice and license conditions from IBX.
7	*
8	* Except for those parts dervied from IBX, contents of this file are subject
9	* to the Initial Developer's Public License Version 1.0 (the "License"); you
10	* may not use this file except in compliance with the License. You may obtain a
11	* copy of the License here:
12	*
13	* http://www.firebirdsql.org/index.php?op=doc&id=idpl
14	*
15	* Software distributed under the License is distributed on an "AS
16	* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
17	* implied. See the License for the specific language governing rights
18	* and limitations under the License.
19	*
20	* The Initial Developer of the Original Code is Tony Whyman.
21	*
22	* The Original Code is (C) 2016 Tony Whyman, MWA Software
23	* (http://www.mwasoftware.co.uk).
24	*
25	* All Rights Reserved.
26	*
27	* Contributor(s): ______________________________________.
28	*
29	*)
30	unit FBStatement;
31	{$IFDEF MSWINDOWS}
32	{$DEFINE WINDOWS}
33	{$ENDIF}
34
35	{$IFDEF FPC}
36	{$mode delphi}
37	{$codepage UTF8}
38	{$interfaces COM}
39	{$ENDIF}
40
41	interface
42
43	uses
44	Classes, SysUtils, IB, FBClientAPI, FBSQLData, FBOutputBlock, FBActivityMonitor,
45	FBTransaction;
46
47	type
48	TPerfStatistics = array[psCurrentMemory..psFetches] of Int64;
49
50	{ TFBStatement }
51
52	TFBStatement = class(TActivityReporter)
53	private
54	FAttachmentIntf: IAttachment;
55	protected
56	FTransactionIntf: ITransaction;
57	FExecTransactionIntf: ITransaction;
58	FSQLStatementType: TIBSQLStatementTypes; { Select, update, delete, insert, create, alter, etc...}
59	FSQLDialect: integer;
60	FOpen: boolean;
61	FPrepared: boolean;
62	FPrepareSeqNo: integer; {used to check for out of date references from interfaces}
63	FSQL: AnsiString;
64	FProcessedSQL: AnsiString;
65	FHasParamNames: boolean;
66	FBOF: boolean;
67	FEOF: boolean;
68	FSingleResults: boolean;
69	FGenerateParamNames: boolean;
70	FChangeSeqNo: integer;
71	FCollectStatistics: boolean;
72	FStatisticsAvailable: boolean;
73	FBeforeStats: TPerfStatistics;
74	FAfterStats: TPerfStatistics;
75	procedure CheckHandle; virtual; abstract;
76	procedure CheckTransaction(aTransaction: ITransaction);
77	procedure GetDsqlInfo(info_request: byte; buffer: ISQLInfoResults); overload; virtual; abstract;
78	procedure InternalPrepare; virtual; abstract;
79	function InternalExecute(aTransaction: ITransaction): IResults; virtual; abstract;
80	function InternalOpenCursor(aTransaction: ITransaction): IResultSet; virtual; abstract;
81	procedure FreeHandle; virtual; abstract;
82	procedure InternalClose(Force: boolean); virtual; abstract;
83	function TimeStampToMSecs(const TimeStamp: TTimeStamp): Int64;
84	public
85	constructor Create(Attachment: IAttachment; Transaction: ITransaction;
86	sql: AnsiString; SQLDialect: integer);
87	constructor CreateWithParameterNames(Attachment: IAttachment; Transaction: ITransaction;
88	sql: AnsiString; SQLDialect: integer; GenerateParamNames: boolean =false);
89	destructor Destroy; override;
90	procedure Close;
91	procedure TransactionEnding(aTransaction: ITransaction; Force: boolean);
92	property SQLDialect: integer read FSQLDialect;
93
94	public
95	function GetSQLParams: ISQLParams; virtual; abstract;
96	function GetMetaData: IMetaData; virtual; abstract;
97	function GetRowsAffected(var SelectCount, InsertCount, UpdateCount,
98	DeleteCount: integer): boolean;
99	function GetSQLStatementType: TIBSQLStatementTypes;
100	function GetSQLText: AnsiString;
101	function GetSQLDialect: integer;
102
103	{GetDSQLInfo only supports isc_info_sql_stmt_type, isc_info_sql_get_plan, isc_info_sql_records}
104	procedure Prepare(aTransaction: ITransaction=nil); virtual;
105	function Execute(aTransaction: ITransaction=nil): IResults;
106	function OpenCursor(aTransaction: ITransaction=nil): IResultSet;
107	function CreateBlob(paramName: AnsiString): IBlob; overload;
108	function CreateBlob(index: integer): IBlob; overload;
109	function CreateBlob(column: TColumnMetaData): IBlob; overload; virtual; abstract;
110	function CreateArray(paramName: AnsiString): IArray; overload;
111	function CreateArray(index: integer): IArray; overload;
112	function CreateArray(column: TColumnMetaData): IArray; overload; virtual; abstract;
113	function GetAttachment: IAttachment;
114	function GetTransaction: ITransaction;
115	function GetDSQLInfo(Request: byte): ISQLInfoResults; overload;
116	procedure SetRetainInterfaces(aValue: boolean); virtual;
117	procedure EnableStatistics(aValue: boolean);
118	function GetPerfStatistics(var stats: TPerfCounters): boolean;
119	property ChangeSeqNo: integer read FChangeSeqNo;
120	property SQLParams: ISQLParams read GetSQLParams;
121	property SQLStatementType: TIBSQLStatementTypes read GetSQLStatementType;
122	end;
123
124	implementation
125
126	uses FBMessages;
127
128	{ TFBStatement }
129
130	procedure TFBStatement.CheckTransaction(aTransaction: ITransaction);
131	begin
132	if (aTransaction = nil) then
133	IBError(ibxeTransactionNotAssigned,[]);
134
135	if not aTransaction.InTransaction then
136	IBError(ibxeNotInTransaction,[]);
137	end;
138
139	function TFBStatement.TimeStampToMSecs(const TimeStamp: TTimeStamp): Int64;
140	begin
141	Result := TimeStamp.Time + Int64(timestamp.date)*msecsperday;
142	end;
143
144	constructor TFBStatement.Create(Attachment: IAttachment;
145	Transaction: ITransaction; sql: AnsiString; SQLDialect: integer);
146	begin
147	inherited Create(Transaction as TFBTransaction,2);
148	FAttachmentIntf := Attachment;
149	FTransactionIntf := Transaction;
150	FSQLDialect := SQLDialect;
151	FSQL := sql;
152	end;
153
154	constructor TFBStatement.CreateWithParameterNames(Attachment: IAttachment;
155	Transaction: ITransaction; sql: AnsiString; SQLDialect: integer;
156	GenerateParamNames: boolean);
157	begin
158	FHasParamNames := true;
159	FGenerateParamNames := GenerateParamNames;
160	Create(Attachment,Transaction,sql,SQLDialect);
161	end;
162
163	destructor TFBStatement.Destroy;
164	begin
165	Close;
166	FreeHandle;
167	inherited Destroy;
168	end;
169
170	procedure TFBStatement.Close;
171	begin
172	InternalClose(false);
173	end;
174
175	procedure TFBStatement.TransactionEnding(aTransaction: ITransaction;
176	Force: boolean);
177	begin
178	if FOpen and (FExecTransactionIntf = aTransaction) then
179	InternalClose(Force);
180
181	if FTransactionIntf = aTransaction then
182	begin
183	FreeHandle;
184	FPrepared := false;
185	end;
186	end;
187
188	function TFBStatement.GetRowsAffected(var SelectCount, InsertCount,
189	UpdateCount, DeleteCount: integer): boolean;
190	var
191	RB: ISQLInfoResults;
192	i, j: integer;
193	begin
194	InsertCount := 0;
195	UpdateCount := 0;
196	DeleteCount := 0;
197	Result := FPrepared;
198	if not Result then Exit;
199
200	RB := GetDsqlInfo(isc_info_sql_records);
201
202	for i := 0 to RB.Count - 1 do
203	with RB[i] do
204	case getItemType of
205	isc_info_sql_records:
206	for j := 0 to Count -1 do
207	with Items[j] do
208	case getItemType of
209	isc_info_req_select_count:
210	SelectCount := GetAsInteger;
211	isc_info_req_insert_count:
212	InsertCount := GetAsInteger;
213	isc_info_req_update_count:
214	UpdateCount := GetAsInteger;
215	isc_info_req_delete_count:
216	DeleteCount := GetAsInteger;
217	end;
218	end;
219	end;
220
221	function TFBStatement.GetSQLStatementType: TIBSQLStatementTypes;
222	begin
223	Result := FSQLStatementType;
224	end;
225
226	function TFBStatement.GetSQLText: AnsiString;
227	begin
228	Result := FSQL;
229	end;
230
231	function TFBStatement.GetSQLDialect: integer;
232	begin
233	Result := FSQLDialect;
234	end;
235
236	procedure TFBStatement.Prepare(aTransaction: ITransaction);
237	begin
238	if FPrepared then FreeHandle;
239	if aTransaction <> nil then
240	begin
241	RemoveMonitor(FTransactionIntf as TFBTransaction);
242	FTransactionIntf := aTransaction;
243	AddMonitor(FTransactionIntf as TFBTransaction);
244	end;
245	InternalPrepare;
246	end;
247
248	function TFBStatement.Execute(aTransaction: ITransaction): IResults;
249	begin
250	if aTransaction = nil then
251	Result := InternalExecute(FTransactionIntf)
252	else
253	Result := InternalExecute(aTransaction);
254	end;
255
256	function TFBStatement.OpenCursor(aTransaction: ITransaction): IResultSet;
257	begin
258	Close;
259	if aTransaction = nil then
260	Result := InternalOpenCursor(FTransactionIntf)
261	else
262	Result := InternalOpenCursor(aTransaction);
263	end;
264
265	function TFBStatement.CreateBlob(paramName: AnsiString): IBlob;
266	var column: TColumnMetaData;
267	begin
268	InternalPrepare;
269	column := SQLParams.ByName(paramName) as TSQLParam;
270	if column = nil then
271	IBError(ibxeFieldNotFound,[paramName]);
272	Result := CreateBlob(column);
273	end;
274
275	function TFBStatement.CreateBlob(index: integer): IBlob;
276	begin
277	InternalPrepare;
278	Result := CreateBlob(SQLParams[index] as TSQLParam);
279	end;
280
281	function TFBStatement.CreateArray(paramName: AnsiString): IArray;
282	var column: TColumnMetaData;
283	begin
284	InternalPrepare;
285	column := SQLParams.ByName(paramName) as TSQLParam;
286	if column = nil then
287	IBError(ibxeFieldNotFound,[paramName]);
288	Result := CreateArray(column);
289	end;
290
291	function TFBStatement.CreateArray(index: integer): IArray;
292	begin
293	InternalPrepare;
294	Result := CreateArray(SQLParams[index] as TSQLParam);
295	end;
296
297	function TFBStatement.GetAttachment: IAttachment;
298	begin
299	Result := FAttachmentIntf;
300	end;
301
302	function TFBStatement.GetTransaction: ITransaction;
303	begin
304	Result := FTransactionIntf
305	end;
306
307	function TFBStatement.GetDSQLInfo(Request: byte): ISQLInfoResults;
308	begin
309	Result := TSQLInfoResultsBuffer.Create;
310	GetDsqlInfo(Request,Result);
311	end;
312
313	procedure TFBStatement.SetRetainInterfaces(aValue: boolean);
314	begin
315	RetainInterfaces := aValue;
316	end;
317
318	procedure TFBStatement.EnableStatistics(aValue: boolean);
319	begin
320	if FCollectStatistics <> aValue then
321	begin
322	FCollectStatistics := aValue;
323	FStatisticsAvailable := false;
324	end;
325	end;
326
327	function TFBStatement.GetPerfStatistics(var stats: TPerfCounters): boolean;
328	begin
329	Result := FStatisticsAvailable;
330	if Result then
331	begin
332	stats[psCurrentMemory] := FAfterStats[psCurrentMemory];
333	stats[psDeltaMemory] := FAfterStats[psCurrentMemory] - FBeforeStats[psCurrentMemory];
334	stats[psMaxMemory] := FAfterStats[psMaxMemory];
335	stats[psRealTime] := FAfterStats[psRealTime] - FBeforeStats[psRealTime];
336	stats[psUserTime] := FAfterStats[psUserTime] - FBeforeStats[psUserTime];
337	stats[psReads] := FAfterStats[psReads] - FBeforeStats[psReads];
338	stats[psWrites] := FAfterStats[psWrites] - FBeforeStats[psWrites];
339	stats[psFetches] := FAfterStats[psFetches] - FBeforeStats[psFetches];
340	stats[psBuffers] := FAfterStats[psBuffers];
341	end;
342	end;
343
344	end.
345