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EgonHugeist wrote:

that's a good choise but i don't know if they will help us.
I've uploaded one patch for a missing null-byte reservation but that patch will not solve your problem, i think. Rev. 1346

EgonHugeist wrote: Do you have the same trouble if you use the normal DBGrid?

EgonHugeist wrote:

Hmm where to start is a good question. I'm still thinking it is a memory problem. So open ZdbcCache again and goto:

Code: Select all

  Creates this object and assignes the main properties.
  @param ColumnsInfo a collection with column information.
%u7d
constructor TZRowAccessor.Create%u28ColumnsInfo%u3a TObjectList%u29;
var
  I%u3a Integer;
  Current%u3a TZColumnInfo;
begin
  FBuffer %u3a= nil;
  FColumnCount %u3a= ColumnsInfo.Count;
  FColumnsSize %u3a= 0;
  SetLength%u28FColumnNames, FColumnCount%u29;
  SetLength%u28FColumnCases, FColumnCount%u29;
  SetLength%u28FColumnTypes, FColumnCount%u29;
  SetLength%u28FColumnLengths, FColumnCount%u29;
  SetLength%u28FColumnOffsets, FColumnCount%u29;
  SetLength%u28FColumnDefaultExpressions, FColumnCount%u29;
  FHasBlobs %u3a= False;

  for I %u3a= 0 to FColumnCount - 1 do
  begin
    Current %u3a= TZColumnInfo%u28ColumnsInfo%u5bI%u5d%u29;
    FColumnNames%u5bI%u5d %u3a= Current.ColumnName;
    FColumnCases%u5bI%u5d %u3a= Current.CaseSensitive;
    FColumnTypes%u5bI%u5d %u3a= Current.ColumnType;
    FColumnLengths%u5bI%u5d %u3a= GetColumnSize%u28Current%u29;
    FColumnOffsets%u5bI%u5d %u3a= FColumnsSize;
    FColumnDefaultExpressions%u5bI%u5d %u3a= Current.DefaultExpression;
    Inc%u28FColumnsSize, FColumnLengths%u5bI%u5d + 1%u29;
    if FColumnsSize > SizeOf%u28TZByteArray%u29-1 then
      raise EZSQLException.Create%u28SRowBufferWidthExceeded%u29;
    FHasBlobs %u3a= FHasBlobs
      or %u28FColumnTypes%u5bI%u5d in %u5bstAsciiStream, stUnicodeStream, stBinaryStream%u5d%u29;
  end;
  FRowSize %u3a= FColumnsSize + RowHeaderSize;
end;

set a breakpoint on the line Inc(FColumnsSize, FColumnLengths + 1);

and check the FColumnsSize. An overload should normaly raise an exception.

function TZAbstractRODataset.GetFieldData(Field: TField; Buffer: Pointer;
  NativeFormat: Boolean): Boolean;
begin
  try
  if Field.DataType in [ftWideString] then
    NativeFormat := True;
  Result := inherited GetFieldData(Field, Buffer, NativeFormat);
  except
    ShowMessage('FColumnsSize: ' + IntToStr(RowAccessor.ColumnsSize));
  end;
end;

Another possibility. Try to limit the selected rows like: select * from .. where .. limit 10). And check the issue.

Try to use the TZReadOnlyQuery. That component needs only the half memory. Does it work now?

I have the impression that this cxGridand MemTable does double cache the values too which does the dbGrid not. Which means Zeos allocates the whole memory of the Columnsize+RowHeader x2 for the internal and cached ResultSets. The cxGrid/MemTableEh does that too eventually? I don't know. Which means the memory increases x3 or more because i don't now anything about how the two components behave.

That you can watch if you open the taskmanager and check what happens with the used memory.

Maybe it would be helpfull if you add that thread as link to your request of the cx-company?