PostgreSQL: Aggregate Push-down in postgres_fdw

It's exciting times in PostgreSQL for those who are using postgres_fdw or Foreign Data Wrappers (FDWs) in general. Users often complained that a simple count(*) on a foreign table was slow since PostgreSQL required to pull all the rows from the foreign server just to count them to produce count(*). “What a waste of resources,” they complained, “Why doesn’t it just get the count from the foreign se

[wyukawa]

うーんと、これは結局9.6でもpush downできるってことで良いのかな。