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,
theindexed one is the biggest and get's toasted first. And if all the data is of nature that compression
doesn'tgain 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!
> > In the meantime we should decide a safe maximum
> > index tuple size and emit an explanative error message on the
> > attempt to insert oversized index entries instead of possibly
> > corrupting the index.
>
> 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.
Jan
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