Hi,

I have been experiencing AV's in DBISAM, when freeing objects, they appear to be random, but since I upgraded to the later versions my users have been expericeing these
kind of frequently, always seems to be when freeing objects

This example below was caused from this piece of code. Line 5079 in Alldata is  the qry.free from this section of code.

I know these things are very hard to see why this would occur, but im hoping maybe something would ring a bell

Thanks
Clive.

------------------------------------------
qry := TDBISAMQuery.Create(nil);
 try
   ExecuteSQL('select round(a.value - l.value) as value,period '+
            ' from rpt_generic_detail a '+
            ' inner join rpt_generic_detail l on a.period = l.period and a.scenario_code = l.scenario_code ' +
            ' where a.rowid = 38 and l.rowid = 39 and a.scenario_code = -2 group by period having value <> 0 order by period JOINOPTIMIZECOSTS',qry);

   if frm_realyser.lbl_balance.Visible then
     frm_realyser.lbl_balance.Color := clyellow
   else
   begin
     frm_realyser.lbl_balance.Caption := '[Balance sheet does not balance, Please contact support] ';
     frm_realyser.lbl_balance.Color := clred;
   end;

   frm_realyser.lbl_balance.Visible := qry.RecordCount > 0;

   if frm_quick_test.modified then
     data.RefreshScenarioDetail(TRUE);

   frm_quick_test.modified := FALSE;
 finally
   qry.free;
 end;

---------------------------------------------


exception class   : EAccessViolation
exception message : Access violation at address 00586D92 in module 'realyser.exe'. Read of address 00000008.

main thread ($1730):
00586d92 +000a realyser.exe dbisamsq                  TSourceTable.FreeJoins
00589597 +0027 realyser.exe dbisamsq                  TDataQuery.FreeSourceTables
0058914e +0052 realyser.exe dbisamsq                  TDataQuery.Destroy
00404ba8 +0008 realyser.exe System                    TObject.Free
00587c8d +00e5 realyser.exe dbisamsq                  TQueryStatement.Destroy
00404ba8 +0008 realyser.exe System                    TObject.Free
0065596d +000d realyser.exe dbisamtb                  TDBISAMQuery.FreeStatement
00655931 +0069 realyser.exe dbisamtb                  TDBISAMQuery.SetPrepared
00655477 +0007 realyser.exe dbisamtb                  TDBISAMQuery.UnPrepare
00655444 +000c realyser.exe dbisamtb                  TDBISAMQuery.Disconnect
006553ae +0016 realyser.exe dbisamtb                  TDBISAMQuery.Destroy
00404ba8 +0008 realyser.exe System                    TObject.Free
00a2fbbc +07c0 realyser.exe alldata         5079 +147 TData.RefreshCharts
00405382 +002a realyser.exe System                    @HandleFinally
77c61006 +0081 ntdll.dll                              RtlRaiseStatus
77c22c46 +00de ntdll.dll                              RtlUnwind
00405176 +00d2 realyser.exe System                    @HandleAnyException
77c61006 +0081 ntdll.dll                              RtlRaiseStatus
77c60e92 +000a ntdll.dll                              KiUserExceptionDispatcher
0064e5af +0007 realyser.exe dbisamtb                  TDBISAMDataSet.GetRecordCount
00a2fb68 +076c realyser.exe alldata         5072 +140 TData.RefreshCharts
009e8309 +0189 realyser.exe main             805  +25 Tfrm_realyser.WMRealyser_stage1_complete
004e141c +0188 realyser.exe Controls                  TControl.WndProc
004e4487 +0157 realyser.exe Controls                  TWinControl.WndProc
004fbf41 +0421 realyser.exe Forms                     TCustomForm.WndProc
009070db +000b realyser.exe VistaAltFixUnit  243   +1 TFormObj.WndProc
004e4104 +002c realyser.exe Controls                  TWinControl.MainWndProc
0047b1f4 +0014 realyser.exe Classes                   StdWndProc
77da3c85 +000a user32.dll                             DispatchMessageA
0050261f +0083 realyser.exe Forms                     TApplication.ProcessMessage
00502656 +000a realyser.exe Forms                     TApplication.HandleMessage
00502886 +0096 realyser.exe Forms                     TApplication.Run
00a379c9 +1319 realyser.exe realyser         524 +345 initialization
769f3831 +0010 kernel32.dll                           BaseThreadInitThunk

Heres another one.. This occured when disconnecting from the database as the application was exitting.
Seems to be on TSourceTable.FreeJoins both times.

exception number  : 2
exception class   : EAccessViolation
exception message : Access violation at address 00586D92 in module 'realyser.exe'. Read of address 00000008.

main thread ($1730):
00586d92 +000a realyser.exe dbisamsq                  TSourceTable.FreeJoins
00589597 +0027 realyser.exe dbisamsq                  TDataQuery.FreeSourceTables
0058914e +0052 realyser.exe dbisamsq                  TDataQuery.Destroy
00404ba8 +0008 realyser.exe System                    TObject.Free
00587c8d +00e5 realyser.exe dbisamsq                  TQueryStatement.Destroy
00404ba8 +0008 realyser.exe System                    TObject.Free
0065596d +000d realyser.exe dbisamtb                  TDBISAMQuery.FreeStatement
00655931 +0069 realyser.exe dbisamtb                  TDBISAMQuery.SetPrepared
00655477 +0007 realyser.exe dbisamtb                  TDBISAMQuery.UnPrepare
00655444 +000c realyser.exe dbisamtb                  TDBISAMQuery.Disconnect
0064b9b8 +0018 realyser.exe dbisamtb                  TDBISAMDatabase.CloseDataSets
0064b967 +000b realyser.exe dbisamtb                  TDBISAMDatabase.DoDisconnect
0051d9c6 +0072 realyser.exe DB                        TCustomConnection.SetConnected
009ebbe3 +006b realyser.exe main            1761   +9 Tfrm_realyser.ChangeDBStatus
009ebb72 +0002 realyser.exe main            1742   +0 Tfrm_realyser.ChangeDBStatus
009f02ef +011b realyser.exe main            3246  +35 Tfrm_realyser.FormCloseQuery
004fee69 +0055 realyser.exe Forms                     TCustomForm.CloseQuery
Clive <dd@dd.com> wrote:

Hi,

I have been experiencing AV's in DBISAM, when freeing objects, they appear to be random, but since I upgraded to the later versions my users have been expericeing these
kind of frequently, always seems to be when freeing objects

This example below was caused from this piece of code. Line 5079 in Alldata is  the qry.free from this section of code.

I know these things are very hard to see why this would occur, but im hoping maybe something would ring a bell

Thanks
Clive.

------------------------------------------
qry := TDBISAMQuery.Create(nil);
 try
   ExecuteSQL('select round(a.value - l.value) as value,period '+
            ' from rpt_generic_detail a '+
            ' inner join rpt_generic_detail l on a.period = l.period and a.scenario_code = l.scenario_code ' +
            ' where a.rowid = 38 and l.rowid = 39 and a.scenario_code = -2 group by period having value <> 0 order by period JOINOPTIMIZECOSTS',qry);

   if frm_realyser.lbl_balance.Visible then
     frm_realyser.lbl_balance.Color := clyellow
   else
   begin
     frm_realyser.lbl_balance.Caption := '[Balance sheet does not balance, Please contact support] ';
     frm_realyser.lbl_balance.Color := clred;
   end;

   frm_realyser.lbl_balance.Visible := qry.RecordCount > 0;

   if frm_quick_test.modified then
     data.RefreshScenarioDetail(TRUE);

   frm_quick_test.modified := FALSE;
 finally
   qry.free;
 end;

---------------------------------------------


exception class   : EAccessViolation
exception message : Access violation at address 00586D92 in module 'realyser.exe'. Read of address 00000008.

main thread ($1730):
00586d92 +000a realyser.exe dbisamsq                  TSourceTable.FreeJoins
00589597 +0027 realyser.exe dbisamsq                  TDataQuery.FreeSourceTables
0058914e +0052 realyser.exe dbisamsq                  TDataQuery.Destroy
00404ba8 +0008 realyser.exe System                    TObject.Free
00587c8d +00e5 realyser.exe dbisamsq                  TQueryStatement.Destroy
00404ba8 +0008 realyser.exe System                    TObject.Free
0065596d +000d realyser.exe dbisamtb                  TDBISAMQuery.FreeStatement
00655931 +0069 realyser.exe dbisamtb                  TDBISAMQuery.SetPrepared
00655477 +0007 realyser.exe dbisamtb                  TDBISAMQuery.UnPrepare
00655444 +000c realyser.exe dbisamtb                  TDBISAMQuery.Disconnect
006553ae +0016 realyser.exe dbisamtb                  TDBISAMQuery.Destroy
00404ba8 +0008 realyser.exe System                    TObject.Free
00a2fbbc +07c0 realyser.exe alldata         5079 +147 TData.RefreshCharts
00405382 +002a realyser.exe System                    @HandleFinally
77c61006 +0081 ntdll.dll                              RtlRaiseStatus
77c22c46 +00de ntdll.dll                              RtlUnwind
00405176 +00d2 realyser.exe System                    @HandleAnyException
77c61006 +0081 ntdll.dll                              RtlRaiseStatus
77c60e92 +000a ntdll.dll                              KiUserExceptionDispatcher
0064e5af +0007 realyser.exe dbisamtb                  TDBISAMDataSet.GetRecordCount
00a2fb68 +076c realyser.exe alldata         5072 +140 TData.RefreshCharts
009e8309 +0189 realyser.exe main             805  +25 Tfrm_realyser.WMRealyser_stage1_complete
004e141c +0188 realyser.exe Controls                  TControl.WndProc
004e4487 +0157 realyser.exe Controls                  TWinControl.WndProc
004fbf41 +0421 realyser.exe Forms                     TCustomForm.WndProc
009070db +000b realyser.exe VistaAltFixUnit  243   +1 TFormObj.WndProc
004e4104 +002c realyser.exe Controls                  TWinControl.MainWndProc
0047b1f4 +0014 realyser.exe Classes                   StdWndProc
77da3c85 +000a user32.dll                             DispatchMessageA
0050261f +0083 realyser.exe Forms                     TApplication.ProcessMessage
00502656 +000a realyser.exe Forms                     TApplication.HandleMessage
00502886 +0096 realyser.exe Forms                     TApplication.Run
00a379c9 +1319 realyser.exe realyser         524 +345 initialization
769f3831 +0010 kernel32.dll                           BaseThreadInitThunk

Clive,

<< I have been experiencing AV's in DBISAM, when freeing objects, they
appear to be random, but since I upgraded to the later versions my users
have been expericeing these kind of frequently, always seems to be when
freeing objects

This example below was caused from this piece of code. Line 5079 in Alldata
is  the qry.free from this section of code. >>

Could you send me the tables that you're using to execute that query ?

Thanks,

--
Tim Young
Elevate Software
www.elevatesoft.com

table is attached
Cheers
Clive.


Could you send me the tables that you're using to execute that query ?

Clive,

<< table is attached >>

I've run it in a loop 1000 times and I can't reproduce it.  This is running
local on your end, correct ?

--
Tim Young
Elevate Software
www.elevatesoft.com

Yes, I cant reproduce it either..

Its not always that query, more than not its when the database is disconnecting, Im pretty sure it started with B4, I have reverted back to B2 and no problems so far.
The other issue that started happening with B4 is that the backup command is corrupting the database tables, At least thats what it think it is because the tables all work
fine, then as soon as I do a Save (backup) , then restore the backup a random table is corrupt. I hademailed one of these backups to the support email address, but it
bounced back as your server does accept attachments. Im hoping you still have it in the mail server somewhere though.




"Tim Young [Elevate Software]" <timyoung@elevatesoft.com> wrote:

Clive,

<< table is attached >>

I've run it in a loop 1000 times and I can't reproduce it.  This is running
local on your end, correct ?

--
Tim Young
Elevate Software
www.elevatesoft.com

Clive,

<< Its not always that query, more than not its when the database is
disconnecting, Im pretty sure it started with B4, I have reverted back to B2
and no problems so far. >>

That could simply be a coincidence due to the way the memory manager works.
I just ran into this recently with EDB.  There was an issue that the Delphi
memory manager would raise an AV on, but the FastMM memory manager would
not.  It simply came down to a difference in the way the two worked.

BTW, is there any multi-threading going on in the application ?  Also, are
you using a custom memory manager ?

--
Tim Young
Elevate Software
www.elevatesoft.com

Yes, im using FastMM and the application is Multi-threaded,

All my threads are isolated, all have their own sessions and databases and there is no communication with the parent other than the posting of messages back using
POSTMESSAGE.

Im pretty confident in the multi-threaded stuff as its been operating for a few years without much trouble,  but im happy to email you the source if you wanted to look at how im
doing it.

"Tim Young [Elevate Software]" <timyoung@elevatesoft.com> wrote:

Clive,

<< Its not always that query, more than not its when the database is
disconnecting, Im pretty sure it started with B4, I have reverted back to B2
and no problems so far. >>

That could simply be a coincidence due to the way the memory manager works.
I just ran into this recently with EDB.  There was an issue that the Delphi
memory manager would raise an AV on, but the FastMM memory manager would
not.  It simply came down to a difference in the way the two worked.

BTW, is there any multi-threading going on in the application ?  Also, are
you using a custom memory manager ?

--
Tim Young
Elevate Software
www.elevatesoft.com

Clive,

<< Yes, im using FastMM and the application is Multi-threaded,

All my threads are isolated, all have their own sessions and databases and
there is no communication with the parent other than the posting of messages
back using POSTMESSAGE.

Im pretty confident in the multi-threaded stuff as its been operating for a
few years without much trouble,  but im happy to email you the source if you
wanted to look at how im doing it. >>

Sure, send it on over.  It's probably fine, but when you have a case that
isn't reproducible by itself, and the app is multi-threaded, I have to check
all the bases.

--
Tim Young
Elevate Software
www.elevatesoft.com