Hi When I tested json_populate_function in test http://stackoverflow.com/questions/7711432/how-to-set-value-of-composite-variable-field-using-dynamic-sql/28673097#28673097 I found a small issue
create type pt as (a int, b int); postgres=# select json_populate_record('(10,20)'::pt, '{}'); WARNING: TupleDesc reference leak: TupleDesc 0x7f10fcf41400 (567018,-1) still referenced json_populate_record ---------------------- (10,20) (1 row) jsonb is ok postgres=# select jsonb_populate_record('(10,20)'::pt, '{}'); jsonb_populate_record ----------------------- (10,20) (1 row) Regards Pavel