TStringList of objects taking up tons of memory in Delphi XE

Question

I\'m working on a simulation program.

One of the first things the program does is read in a huge file (28 mb, about 79\'000 lines,), parse each line (about 150 field

Answer 1

In addition to Andreas' post:

Before Delphi 2009, a string header occupied 8 bytes. Starting with Delphi 2009, a string header takes 12 bytes. So every unique string uses 4 bytes more than before, + the fact that each character takes twice the memory.

Also, starting with Delphi 2010 I believe, TObject started using 8 bytes instead of 4. So for each single object created by delphi, delphi now uses 4 more bytes. Those 4 bytes were added to support the TMonitor class I believe.

If you're in desperate need to save memory, here's a little trick that could help if you have a lot of string value that repeats themselve.

var
  uUniqueStrings : TStringList;

function ReduceStringMemory(const S : String) : string;
var idx : Integer;
begin
  if not uUniqueStrings.Find(S, idx) then
    idx := uUniqueStrings.Add(S);

  Result := uUniqueStrings[idx]
end;

Note that this will help ONLY if you have a lot of string values that repeat themselves. For exemple, this code use 150mb less on my system.

var sl : TStringList;
  I: Integer;
begin
  sl := TStringList.Create;
  try
    for I := 0 to 5000000 do
      sl.Add(ReduceStringMemory(StringOfChar('A',5)));every
  finally
    sl.Free;
  end;
end;