Re: [HACKERS] Surjective functional indexes

On 10 January 2018 at 09:54, Konstantin Knizhnik
<k.knizhnik@postgrespro.ru> wrote:

> Sorry, issue with documentation is fixed.

OK, thanks.

Patch appears to work cleanly now.

I'm wondering now about automatically inferring "recheck_on_update =
true" for certain common datatype/operators. It doesn't need to be an
exhaustive list, but it would be useful if we detected the main use
case of

(JSONB datatype column)->>CONSTANT

Seems like we could do a test to see if the index function is
FUNCTION(COLUMNNAME, CONSTANTs...)
{JSONB, ->>} or
{jsonb_object_field_text(Columnname, Constant)}
{substring(Columname, Constants...)}

It would be a shame if people had to remember to use this for the
common and obvious cases.

-- 
Simon Riggs                http://www.2ndQuadrant.com/
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