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

Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> writes:
> On 7/25/16 3:26 PM, Andrew Gierth wrote:
>> The issue I ran into was the exact same one as in the JDBC thread I
>> linked to earlier: correctly interpreting pg_index.indoption (to get the
>> ASC / DESC and NULLS FIRST/LAST settings), which requires knowing
>> whether amcanorder is true to determine whether to look at the bits at
>> all.

> Maybe we should provide a facility to decode those bits then?

Yeah. I'm not very impressed by the underlying assumption that it's
okay for client-side code to hard-wire knowledge about what indoption
bits mean, but not okay for it to hard-wire knowledge about which index
AMs use which indoption bits. There's something fundamentally wrong
in that. We don't let psql or pg_dump look directly at indoption, so
why would we think that third-party client-side code should do so?

Andrew complained upthread that pg_get_indexdef() was too heavyweight
for his purposes, but it's not clear to me what he wants instead.

regards, tom lane