I've tried arrays but plpython does not support returning arrays of custom db types (which is what I'd need to do)
On Monday, 8 October 2012, Merlin Moncure wrote:
On Mon, Oct 8, 2012 at 3:14 PM, Seref Arikan <serefarikan@kurumsalteknoloji.com> wrote: > Greetings, > I have a binary blog which is passed to a plpython function by a plpgsql > function. plpython is used to create 2 different transformations of this > binary blob to sets of postgresql type instances. > The flow is: blob -> plpython -> canonical python based data model -> (set > of db_type_As + set of db_type_Bs) > The problem is, transforming the binary blob to postgresql is expensive, and > a single binary blob is the source of two transformations. I have not found > a way of returning to sets of data form the plpython function. > At the moment, I have two options: > 1) calling two functions in plpython that use the same blob and return > different sets of postgresql types (heavyweight transformation will happen > twice: bad) > 2) creating two temp tables and calling the plpython function which in turn > writes to these temp tables, and then using the temp tables from plpgsql. > > Do you think there are any other options that I might be missing? What would > be the most efficient way of passing temp tables to plpython function?
Are the two sets the same size? If so, you probably want to do a vanilla SRF. If not, consider a a composite containing arrays:
create type foo as(a int[], b int[]);
CREATE FUNCTION get_stuff() RETURNS foo AS $$ return [(1, 2, 3, 4, 5), (1,2,3)]; $$ LANGUAGE plpythonu;
select * from get_stuff(); postgres=# select * from get_stuff(); a | b -------------+--------- {1,2,3,4,5} | {1,2,3}
