Subject Re: [Firebird-Architect] Question about limits in fb 2.5 or 3.0
Author Dmitry Yemanov
Ann W. Harrison wrote:
>
>> ... while the 64k page size requires
>> to change everything into ULONG. The latter implies an ODS change as well.
>
> Sorry, I may be particularly dumb today, but I don't see why a 64K page
> requires either universal ULONGs or an ODS change. All offsets on a
> 64K page can be referenced with an unsigned 16 bit number. BDB's are
> another issue - they would require larger blocks and that might
> propagate pretty widely in the runtime structures, but that's not
> ODS - or is it?

Page offsets surely can still be USHORT. But the whole page size - not.
Look at dbb_page_size and its ODS counterpart hdr_page_size -- both are
currently USHORTs and thus cannot hold a value of 65536. You may find
many local variables that get assigned with dbb_page_size, compared with
it, etc. And extending hdr_page_size means an ODS change, doesn't it (if
we don't speak about encoding it some way, e.g. storing an appropriate
power of two instead of the plain number)?


Dmitry