> Philip Warner wrote:
> > At 14:02 11/07/00 +0200, Jan Wieck wrote:
> > > AFAICS, we need to detoast values for index inserts allways
> > > and have another toaster inside the index access methods at
> > > some day.
> >
> > We might not need it...at least not in the furst pass.
>
> The thing is actually broken and needs a fix. As soon as
> "text" is toastable, it can happen everywhere that text is
> toasted even if it's actual plain value would perfectly fit
> into an index tuple. Think of a table with 20 text columns,
> where the indexed one has a 1024 bytes value, while all
> others hold 512 bytes. In that case, the indexed one is the
> biggest and get's toasted first. And if all the data is of
> nature that compression doesn't gain enough, it might still
> be the biggest one after that step and will be considered for
> move off ... boom.
>
> We can't let this in in the first pass!
Have you added a minimum size for a value to actually be considered
for toasting ? Imho some lower border between 64 and 256 bytes per value
would be useful, not only the row size.
Imho the same logic should apply to choose wheather a fixed (max) size
column
qualifys for toasting (e.g. varchar(32) should never qualify for toasting)
Andreas
