Use of FREE Command

Question

Hi,
Can anybody answer pros and cons of using FREE Command?
Regards
Nilesh

Answer 1

Serdar's post is correct, though I would like to add a clarification if I may.
Say you have an internal table ITAB with a record length of around 1K, holding around 1,000 rows.  If we look at memory allocation simply, we can say that this internal table ITAB occupies about 1MB of memory.
If you use the statement <b>REFRESH ITAB</b> then afterwards the internal table ITAB will be empty, but the internal table will not release the 1MB of memory previously allocated.  This can have a performance advantage if your just going to fill the internal table up again, as it re-uses this memory.
If you use the statement <b>FREE ITAB</b> then afterwards, the internal table will be empty but the allocated memory will also be released.  Thus if you subsequently repopulate the internal table, the work process will have to reallocate memory again.  Using FREE can be particularly important in long-running, high volume processes, when an internal table is no longer required.
FREE originated as a command to manage internal tables.  It has subsequently be extended to explicitly destroy class instances in ABAP Objects (as well as OLE2 automation references via FREE OBJECT ...).
Using <b>FREE objref</b> is the same as using <b>CLEAR objref</b>.  That is, the variable objref will no longer hold a reference to the class instance.  Whether the object is actually destroyed by the garbage collector depends on whether other references to the instance are still held.
Cheers,
Scott
Message was edited by Scott Barden following clarification by Klaus.