Re: Big 7.1 open items

Tom Lane wrote:
> JanWieck@t-online.de (Jan Wieck) writes:
> >     There are also disadvantages.
>
> >         You can run out of space even if there  are  plenty  GB's
> >         free  on  your  disks.   You  have  to create tablespaces
> >         explicitly.
>
> Not to mention the reverse: if I read this right, you have to suck
> up your GB's long in advance of actually needing them.  That's OK
> for a machine that's dedicated to Oracle ... not so OK for smaller
> installations, playpens, etc.

    Right,  the design is perfect for a few databases with a more
    or less stable size and schema (slow to medium  growth).  The
    problem  is, that production databases tend to fall into that
    behaviour and that might be  a  reason  for  so  many  people
    asking for Oracle compatibility - they want to do development
    in the high  flexible  Postgres  environment,  while  running
    their production server under Oracle :-(.

> I'm not convinced that there's anything fundamentally wrong with
> doing storage allocation in Unix files the way we have been.
>
> (At least not when we're sitting atop a well-done filesystem,
> which may leave the Linux folk out in the cold ;-).)

    I'm  with  you on that, even if I'm one of the Linux loosers.
    The only point that really strikes me is that in  our  system
    you  might  end  up with a corrupted file system because some
    inode changes didn't make it to the disk before a crash. Even
    if  using  fsync() instead of fdatasync() (what we cannot use
    at all and that's a pain from the performance PoV).   In  the
    Oracle world, that could only happen during

        ALTER TABLESPACE <tsname> ADD DATAFILE ...

    which  is  a  fairly seldom command, issued usually by the DB
    admin (at  least  it  requires  admin  privileges)  and  thus
    ensures  the "admin is there and already paying attention". A
    little detail not to underestimate IMHO.


Jan

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