Re: update on TOAST status' - Mailing list pgsql-hackers

From JanWieck@t-online.de (Jan Wieck)
Subject Re: update on TOAST status'
Date
Msg-id 200007111308.PAA17886@hot.jw.home
Whole thread Raw
In response to Re: update on TOAST status'  (Philip Warner <pjw@rhyme.com.au>)
Responses Re: update on TOAST status'
List pgsql-hackers
Philip Warner wrote:
> At 14:38 11/07/00 +0200, Jan Wieck wrote:
> >> Can I suggest that we also put out a warning when defining an index using a
> >> field with a (potentially) unlimited size? Indexing a text field will
> >> mostly be a bizarre thing to do, but, eg, indexing the first 255 chars of a
> >> text field (via substr) might not be.
> >
> >    Marking it BOLD somewhere in the release  notes,  the  CREATE
> >    INDEX  doc  and  some  other  places should be enough. Such a
> >    message at every CREATE INDEX is annoying.
>
> The suggestion was only if the index contained a text, lztext etc field,
> but no problem. The way I read your suggestion was that I'd get a real
> error when doing an insert if the text was too large.
   Yes, that's what I'm after. It's too fragile IMHO to check on   multi column indices with char(n) or so  if
resulting index   tuples will fit in the future.
 
   The  atttypmod  field  on NUMERIC columns for example doesn't   tell the easy way how big the internal
representation might   grow.  And  what  about variable size user defined types that   are marked toastable?  Can you
estimatethe maximum  internal   storage size for them?
 


Jan

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