SUMMARY OF THREAD The design of patch 0001 is agreed upon by everyone on the thread (so far). This adds the PARTIAL_AGGREGATE label for aggregates, which will cause the finalfunc not to run. It also starts using PARTIAL_AGGREGATE for pushdown of aggregates in postgres_fdw. In 0001 PARTIAL_AGGREGATE is only supported for aggregates with a non-internal/pseudo type as the stype.
The design for patch 0002 is still under debate. This would expand on the functionality added by adding support for PARTIAL_AGGREGATE for aggregates with an internal stype. This is done by returning a byte array containing the bytes that the serialfunc of the aggregate returns. A competing proposal for 0002 is to instead change aggregates to not use an internal stype anymore, and create dedicated types. The main downside here is that infunc and outfunc would need to be added for text serialization, in addition to the binary serialization. An open question is: Can we change the requirements for CREATE TYPE, so that types can be created without infunc and outfunc. WHAT IS NEEDED? The things needed for this patch are that docs need to be added, and detailed codereview needs to be done. Feedback from more people on the two competing proposals for 0002 would be very helpful in making a decision.
