Re: Fixing GIN for empty/null/full-scan cases

On Tue, Jan 4, 2011 at 4:09 PM, Tom Lane  wrote:
> * Existing GIN indexes are upwards compatible so far as on-disk storage
> goes, but they will of course be missing entries for empty, null, or
> null-containing items.  Users who want to do searches that should find
> such items will need to reindex after updating to 9.1.

This is the only part of this proposal that bothers me a little bit.
It would be nice if the system could determine whether a GIN index is
"upgraded from 9.0 or earlier and thus doesn't contain these entries"
- and avoid trying to use the index for these sorts of queries in
cases where it might return wrong answers.

-- 
Robert Haas
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