"Donald Fraser" writes:
Is the returned value of a function defined as IMMUTABLE cached =
globally?
"Tom Lane" writes:
No, in fact it isn't cached at all. IMMUTABLE tells the planner that
it's OK to fold a function call with constant inputs to a constant
result value at plan time. Nothing more.
Ok I'm sort of clutching at straws here...
What about this scenario: I'm aware that sql statements within PL/pgSQL
functions get cached. Therefore if the query planner can fold a function with a
constant result, could that query plan get cached by PL/pgSQL with a folded
value?
Regards
Donald Fraser
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
