Thread: About TOAST and indices

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
beimplemented in   v7.1.
 
   So at the time  beeing,  I  think  index  tuples  should  not   contain  any external toast references. I'll change
theheap-   am/toaster combo temporarily to do that.  All  that  will  be   covered  by  #ifdef, so we can switch back
easilyat the time   we have file versioning to unlimit indexed attribute sizes as   well.
 
   Comments?


Jan

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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

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

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