On Jun14, 2011, at 07:15 , Tom Lane wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> On Mon, Jun 13, 2011 at 7:47 PM, Bruce Momjian <bruce@momjian.us> wrote:
>>> No, it does not. Under what circumstances should I issue a suggestion
>>> to reindex, and what should the text be?
>
>> It sounds like GIN indexes need to be reindexed after upgrading from <
>> 9.1 to >= 9.1.
>
> Only if you care whether they work for corner cases such as empty
> arrays ... corner cases which didn't work before 9.1, so very likely
> you don't care.
We also already say "To fix this, do REINDEX INDEX ... " in the errhint
of "old GIN indexes do not support whole-index scans nor searches for nulls".
best regards,
Florian Pflug