On Thu, May 2, 2013 at 11:11 AM, Ivan Přenosil <Ivan.Prenosil@...>wrote:

Many things that are very true and valuable. I would like to clarify one
thing:

>
> The problem is that UPDATE will never change
>
> record's location, it will stay on "it's" page "forever".
>
>
That is absolutely true, but possibly misleading to the naive. Every
record
has a "primary version" which is the most recently created version. When you
store a record, the primary version goes on a data page. That data page
will
always hold the primary record version, no matter how many times the record
is modified - that's the "home page" for that record. Each modification
creates
a new primary record version, which must be on the record's home page. If
there's room on the page for a second version, fine. If not, Firebird moves
the
older version to a different page and puts the new version on the reclaimed
space on the home page.

Good luck,

Ann


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