Hi, On 2016/10/05 14:19, Chenxi Li wrote: > Hello, > > I'm reading some papers about aggregation push down like in " > https://ub-madoc.bib.uni-mannheim.de/37228/1/main.pdf" and " > http://www.vldb.org/conf/1995/P345.PDF". I think it is very useful but very > complex to implement. In some complex queries, it can be a lot faster. Is > there any plan to do this in the future?
Thanks for the links. On a quick look, I think you are referring to the following section in the document at the first link (and the title of the paper at the second link): 4.2 Applying Eager Aggregation I think someone is working on something like that. Check out the following discussion (currently inactive though): * Partial Aggregation / GROUP BY before JOIN * https://www.postgresql.org/message-id/flat/CAKJS1f9kw95K2pnCKAoPmNw%3D%3D7fgjSjC-82cy1RB%2B-x-Jz0QHA%40mail.gmail.com There is also related work which is under active development: * Aggregate Push Down - Performing aggregation on foreign server * https://www.postgresql.org/message-id/flat/CAM2%2B6%3DW%3Dr_vh2gpccPJ4tc%3D%2BhFm4UGQsQdZgt4GiBMYVEk%2B5vg%40mail.gmail.com In this case, the aggregation step is pushed all the way to the remote server where the data resides. It stands to avoid a good deal of unnecessary data traffic across the network. Thanks, Amit -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers