Re: No longer possible to query catalogs for index capabilities?

>>>>> "Tom" == Tom Lane <tgl@sss.pgh.pa.us> writes:
>> With the gutting of pg_am in 9.6, there seems to be no longer any>> way for a query of the system catalogs to
discoverany of the index>> capabilities that were formerly columns in pg_am (notably>> amcanorder, amcanorderbyop,
amclusterable,amsearcharray,>> amsearchnulls).
 
>> Am I missing something or is this a significant oversight?
Tom> It's absolutely not an oversight.  We asked when 65c5fcd35 went inTom> whether there was still any need for that
informationto beTom> available at the SQL level, and nobody appeared to care.
 

Perhaps you were asking the wrong people?
Tom> We could in theory expose a view to show the data --- but since aTom> large part of the point of that change was
tonot need initdb forTom> AM API changes, and to not be constrained to exactlyTom> SQL-compatible representations
withinthat API, I'm disinclined toTom> do so without a fairly compelling argument why it's needed.
 

It could easily be exposed as a function interface of the form
index_has_capability(oid,name) or indexam_has_capability(oid,name)
without any initdb worries.

That would surely be better than the present condition of being
completely unable to get this information from SQL.

-- 
Andrew (irc:RhodiumToad)