On Fri, Apr 7, 2023 at 09:16:14PM -0700, Andres Freund wrote: > On 2023-04-07 22:53:53 -0400, Bruce Momjian wrote: > > > postgres_fdw has no business pushing down calls to non-builtin functions > > > unless the user has explicitly authorized that via the existing > > > whitelisting mechanism. I think you're reinventing the wheel, > > > and not very well. > > > > The patch has you assign an option at CREATE AGGREGATE time if it can do > > push down, and postgres_fdw checks that. What whitelisting mechanism > > are you talking about? async_capable? > > extensions (string) > > This option is a comma-separated list of names of PostgreSQL extensions > that are installed, in compatible versions, on both the local and remote > servers. Functions and operators that are immutable and belong to a listed > extension will be considered shippable to the remote server. This option can > only be specified for foreign servers, not per-table. > > When using the extensions option, it is the user's responsibility that > the listed extensions exist and behave identically on both the local and > remote servers. Otherwise, remote queries may fail or behave unexpectedly.
Okay, this is very helpful --- it is exactly the issue we are dealing with --- how can we know if partial aggregate functions exists on the remote server. (I knew I was going to need API help on this.) So, let's remove the PARTIALAGG_MINVERSION option from the patch and just make it automatic --- we push down builtin partial aggregates if the remote server is the same or newer _major_ version than the sending server. For extensions, if people have older extensions on the same or newer foreign servers, they can adjust 'extensions' above. -- Bruce Momjian <br...@momjian.us> https://momjian.us EDB https://enterprisedb.com Embrace your flaws. They make you human, rather than perfect, which you will never be.
