Hi,

    up to now, TOAST would be a v7.1 show-stopper, because due to
    the upper-block btree references  problem,  it's  not  VACUUM
    safe  if there's a btree index on a toastable attribute (like
    text).

    The only clean way to get rid of these upper-block references
    is to recreate the indices from scratch, instead of vacuuming
    them in the crash-safe manner we do now. But doing  so  needs
    file  versioning,  and I don't expect it to be implemented in
    v7.1.

    So at the time  beeing,  I  think  index  tuples  should  not
    contain  any external toast references. I'll change the heap-
    am/toaster combo temporarily to do that.  All  that  will  be
    covered  by  #ifdef, so we can switch back easily at the time
    we have file versioning to unlimit indexed attribute sizes as
    well.

    Comments?


Jan

--

#======================================================================#
# It's easier to get forgiveness for being wrong than for being right. #
# Let's break this rule - forgive me.                                  #
#================================================== JanWieck@Yahoo.com #



Thu, 20 Jul 2000 17:20:38 +0200 (MEST)
JanWieck@t-online.de (Jan Wieck)
About TOAST and indices
JanWieck@t-online.de (Jan Wieck) writes:
>     So at the time  beeing,  I  think  index  tuples  should  not
>     contain  any external toast references.

Seems like a good stopgap solution.  You'll still allow them to be
compressed in-line, though, right?

			regards, tom lane

Thu, 20 Jul 2000 11:51:48 -0400
Tom Lane <tgl@sss.pgh.pa.us>
Re: About TOAST and indices 
Tom Lane wrote:
> JanWieck@t-online.de (Jan Wieck) writes:
> >     So at the time  beeing,  I  think  index  tuples  should  not
> >     contain  any external toast references.
>
> Seems like a good stopgap solution.  You'll still allow them to be
> compressed in-line, though, right?

    Of  course. There's no problem with in-line compressed items.
    It's only these external references that cause trouble  after
    a vacuum.


Jan

--

#======================================================================#
# It's easier to get forgiveness for being wrong than for being right. #
# Let's break this rule - forgive me.                                  #
#================================================== JanWieck@Yahoo.com #



Thu, 20 Jul 2000 18:41:16 +0200 (MEST)
JanWieck@t-online.de (Jan Wieck)
Re: About TOAST and indices