Re: Datafiles 32 & 64 compatibility

Steve Howard wrote:
> astalavista wrote:
> > >
> > > Think logical!
> > > What is your response?
> > >
> > > NO
> > It was I thought ..
> > Thanks
>
> Actually, they are, depending on the processor endian type. If the
> Oracle version is the same, and the processor endian is the same, all
> you must do is run the utlirp.sql script to invalidate and recompile
> all packages (converts internal format from 32 to 64 bit). We did this
> a couple of years ago when we are on 9.2.0.6.
>

So are you lucky or smart?

It works because most of the data is in oracle's own format: number, date, varchar2, rownum. But have you completely tested everything? I don't think you can. The types of things that would blow up are numeric format, if anything uses that, you are potentially toast. What happens is that some commercial packages wrap numeric data into Oracle datatypes. When that stuff gets pulled out of the db and into a different bit library routine than the one it originally used... well, what do you think -2 32bit will become on 64bit? (I've even seen this problem on a varchar2 stuffed as a numeric sequence, values changed with imp changing charactersets).

So we don't really know what will happen with some of the stuff Oracle uses internally. We can guess, we can test... but we don't have much to guess with and can't really test everything, even Oracle has let 32-bit bugs out at times, we don't have any way of knowing the real differences.

We do know some things have blown up with floating-point problems: Oracle apps and the pentium bug, numerous things on linux including RMAN RAC hanging, and so forth. One has to wonder about anything that is stored RAW by Oracle... or anything that you don't know how Oracle stores it.

Perhaps the best indicator of "can it be done reliably?": Can transportable tablespaces do it? So perhaps the answer is yes, since 8.1 - except for function-based indexes. I wonder why no FBI?

jg

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