Do function calls the cached?

[Daniel Caldeweyher <dcalde@xxxxxxxxx>]

Hi,

I have an expensive function that does a lot of regex and other text analysis. This function relies on several columns of my table and for efficiency/code reuse also has several OUT arguments:

CREATE OR REPLACE FUNCTION extract_keywords(IN l large_table, OUT a text, OUT b text, OUT c text)

  RETURNS record AS

$BODY$

select  l.a ~* 'lots of regex' as a, l.b ~* 'lots of regex' as b, l.c ~* 'lots of regex' as c

from large_table l

$BODY$

  LANGUAGE sql STABLE;

I want to use this function in a view and since I only want the function to be called once I created my view as such:

create view with_keywords as

select x,y,z, (extract_keywords(l.*)).*

from large_table;

However when I then inspect the generated SQL for the view in pgadmin I get:

CREATE VIEW with_keywords AS

SELECT x,y,z, 

 (extract_keywords(l.*)).a AS a,

 (extract_keywords(l.*)).b AS b,

 (extract_keywords(l.*)).c AS c

FROM large_table l;

Does this mean the function gets called three time? The answer in http://stackoverflow.com/questions/20718499/does-postgresql-cache-function-calls suggests that no function call, not even for stable functions, ever gets cached. It also states that I should penalize the function with a high cost. But I don't see how this has any benefit in this case other than mess up the rest of my query plan.

Thanks,

Daniel