Jim Starkey wrote:

> beru7 wrote:
>>
>>I came across this while arguing the pros and cons of different
>>RBDMS's and was wondering why others chose to store the different
>>versions separately when firebird stores them right in the rows' pages.
>>
>
> Simple answer. If the old version is on the same page as the current
> version, there is almost no cost to keeping the old version. No
> additional writes are required when the record is modified, only one
> page when the record is garbage collected, and no additional pages need
> to be read if the old version pointer needs to be followed.
>

However, this works best if the back versions are compressed, so they
fit on the page with the primary version, which, of course, Firebird
does.


Regards,


Ann