Re: Spilling hashed SetOps and aggregates to disk - Mailing list pgsql-hackers

From Andres Freund
Subject Re: Spilling hashed SetOps and aggregates to disk
Date
Msg-id 20180606140129.ymghte3rtv33d5ad@alap3.anarazel.de
Whole thread Raw
In response to Re: Spilling hashed SetOps and aggregates to disk  (Tomas Vondra <tomas.vondra@2ndquadrant.com>)
Responses Re: Spilling hashed SetOps and aggregates to disk
List pgsql-hackers
Hi,

On 2018-06-06 15:58:16 +0200, Tomas Vondra wrote:
> The other issue is that serialize/deserialize is only a part of a problem -
> you also need to know how to do "combine", and not all aggregates can do
> that ... (certainly not in universal way).

There are several schemes where only serialize/deserialize are needed,
no?  There are a number of fairly sensible schemes where there won't be
multiple transition values for the same group, no?

Greetings,

Andres Freund


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