On Wed, Aug 26, 2015 at 7:20 PM, Alexander Korotkov < a.korot...@postgrespro.ru> wrote:
> On Wed, Aug 26, 2015 at 6:50 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > >> Alexander Korotkov <a.korot...@postgrespro.ru> writes: >> > OK. So, as we mentioned before, if we need to expose something of am >> > parameters at SQL-level then we need to write special functions which >> would >> > call amhandler and expose it. >> > Did we come to the agreement on this solution? >> >> I think we were agreed that we should write functions to expose whatever >> needs to be visible at SQL level. I'm not sure that we had a consensus >> on exactly which things need to be visible. >> >> One thought here is that we might not want to just blindly duplicate >> the existing pg_am behavior anyway. For example, the main use of the >> amstrategies column was to allow validation of pg_amop.amopstrategy >> entries --- but in 4 out of the 6 existing AMs, knowledge of the AM alone >> isn't sufficient information to determine the valid set of strategy >> numbers anyway. So inventing a "pg_amstrategies(am oid)" function seems >> like it would be repeating a previous failure. Not quite sure what to >> do instead, though. We could imagine something like "pg_amstrategies(am >> oid, opclass oid)", but I don't see how to implement it without asking >> opclasses to provide a validation function, which maybe is a change we >> don't want to take on here. >> > > Could we add another function to access method interface which would > validate opclass? > Am could validate this way not only strategies, but also supporting > functions. For instance, in GIN, we now require opclass to specify at least > one of consistent and triconsistent. ISTM I would be nice to let the access > method check such conditions. Also, we would be able to check opclass > correction on its creation. Now one can create opclass with missing support > functions which doesn't work. > In the SQL-level we can create function which validates opclass using this > new method. This function can be used in regression tests. > Should I try to implement such new access method function, say 'amvalidate'? ------ Alexander Korotkov Postgres Professional: http://www.postgrespro.com The Russian Postgres Company
