I wrote:
> Greg Stark <stark@mit.edu> writes:
>> For what it's worth there are a number of mentions in the docs of
>> platforms that have non-ieee semantics behaving differently so I
>> wouldn't say we don't support such platforms. If we could avoid the
>> test failures without weakening the tests for other platforms that
>> would be nice. But I don't see any obvious way to do that.
> Yeah. The NaN and Infinity behavioral changes seem like a big problem.
... having said that, it is fair to wonder why the pgstatindex() tests
involve NaNs at all. It's one thing to cope with NaNs if they're present
in user input or the user does a computation that will produce them,
but defining database services that produce NaNs for no especially good
reason is something else again.
A look in the git logs suggests that this particular behavior was
probably completely accidental. We memorialized it as official in commits
af7d18129 & bd165757f, but I would bet a good lunch that zero thought went
into it before that.
I don't care enough about this point to push it forward myself, but
I would support a change to make pgstatindex() return zero rather than
NaN for these statistics on empty indexes.
regards, tom lane