Possible memory leak with SQL function?

Hello list,

Is the following known behaviour, or should I put some time in writing a 
self contained test case?

We have a function that takes a value and returns a ROW type. With the 
function implemented in language SQL, when executing this function in a 
large transaction, memory usage of the backend process increases. 
MemoryContextStats showed a lot of SQL function data. Debugging 
init_sql_fcache() showed that it was for the same function oid each 
time, and the oid was the function from value to ROW type.

When the function is implemented in PL/pgSQL, the memory usage was much 
less.

I'm sorry I cannot be more specific at the moment, such as what is 'much 
less' memory with a PL/pgSQl function, and are there as many SQL 
function data's as calls to the SQL function, because I would have to 
write a test case for this. I was just wondering, if this is known 
behavior of SQL functions vs PL/pgSQL functions, or could it be a bug?

-- 
Yeb Havinga
http://www.mgrid.net/
Mastering Medical Data