On 11/20/2017 04:43 PM, Евгений Шишкин wrote: > > >> On Nov 20, 2017, at 18:29, Tomas Vondra <tomas.von...@2ndquadrant.com> wrote: >> >>> >>> What about instead of dropping column we leave data uncompressed? >>> >> >> That requires you to go through the data and rewrite the whole table. >> And I'm not aware of a DROP command doing that, instead they just drop >> the dependent objects (e.g. DROP TYPE, ...). So per PLOS the DROP >> COMPRESSION METHOD command should do that too. > > Well, there is no much you can do with DROP TYPE. But i'd argue that > compression > is different. We do not drop data in case of DROP STATISTICS or DROP INDEX. >
But those DROP commands do not 'invalidate' data in the heap, so there's no reason to drop the columns. > At least there should be a way to easily alter compression method then. > +1 regards -- Tomas Vondra http://www.2ndQuadrant.com PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
