LONG

I thought about the huge size variable text type a little
more. And I think I could get the following implementation
to work reliable for our upcoming release.

For any relation, having one or more LONG data type
attributes, another relation (named pg_<something>) is
created, accessible only to superusers (and internal access
routines). All LONG data items are stored as a reference
into that relation, split up automatically so the chunks fit
into the installation specific tuple limit size. Items are
added/updated/removed totally transparent.

It would not be indexable (jesus no!) and using it in a WHERE
clause will be expensive. But who ever uses a WHERE on a not
indexable (possibly containing megabytes per item) data type
is a silly fool who should get what he wanted, poor response
times.

I'd like to name it LONG, like Oracle's 2G max. data type.
Even if I intend to restrict the data size to some megabytes
for now. All the data must still be processable in memory,
and there might be multiple instances of one item in memory
at the same time. So a real 2G datatype is impossible with
this kind of approach. But isn't a 64MB #define'd limit
enough for now? This would possibly still blow away many
installations due to limited memory and/or swap space. And we
can adjust that #define in 2001 (an address space odyssey),
when 64bit hardware and plenty of GB real memory is the low
end standard *1).

I already thought that the 8K default BLKSIZE is a little out
of date for today's hardware standards. Two weeks ago I
bought a PC for my kids. It's a 433MHz Celeron, 64MB ram, 6GB
disk - costs about $500 (exactly DM 999,-- at Media Markt).
With the actual on disk cache <-> memory and cache <->
surface transfer rates, the 8K size seems a little archaic to
me.

Thus, if we can get a LONG data type in 7.0, and maybe adjust
the default BLKSIZE to something more up to date, wouldn't
the long tuple item get away silently?

Should I go ahead on this or not?

Jan

*1) Or will it be TB/PB?

I fear to estimate, because it's only a short time ago, that
a 4G hard disk was high-end. Today, IBM offers a 3.5'' disk
with 72G formatted capacity and 64M is the lowest end of real
memory, so where's the limit?

--

#======================================================================#
# It's easier to get forgiveness for being wrong than for being right. #
# Let's break this rule - forgive me. #
#========================================= wieck(at)debis(dot)com (Jan Wieck) #