Hi folks. I notice that immutable flag does nothing when i invoke
my plpgsql function within one session with same args.
tele=# SELECT version();
version
-------------------------------------------------------------
PostgreSQL 7.3.4 on i686-pc-linux-gnu, compiled by GCC 2.96
At first EXPLAIN ANALYZE shown strange runtime :)
[15:41]/0:[EMAIL PROTECTED]:~>time psql -c 'EXPLAIN ANALYZE SELECT calc_total(1466476,
1062363600, 1064955599)' tele
QUERY PLAN
----------------------------------------------------------------------------------
Result (cost=0.00..0.01 rows=1 width=0) (actual time=0.00..0.00 rows=1 loops=1)
Total runtime: 0.02 msec
^^^^^^^^^
(2 rows)
real 0m19.282s
^^^^^^^^^
At second. calc_total() is immutable function:
tele=# SELECT provolatile from pg_proc where proname = 'calc_total' and pronargs =3;
provolatile
-------------
i
but it seems that it's not cached in one session:
[15:38]/0:[EMAIL PROTECTED]:~>psql tele
Welcome to psql 7.3.4, the PostgreSQL interactive terminal.
Type: \copyright for distribution terms
\h for help with SQL commands
\? for help on internal slash commands
\g or terminate with semicolon to execute query
\q to quit
tele=# EXPLAIN ANALYZE SELECT calc_total(1466476, 1062363600, 1064955599);
QUERY PLAN
----------------------------------------------------------------------------------
Result (cost=0.00..0.01 rows=1 width=0) (actual time=0.00..0.00 rows=1 loops=1)
Total runtime: 0.02 msec
(2 rows)
tele=# EXPLAIN ANALYZE SELECT calc_total(1466476, 1062363600, 1064955599);
QUERY PLAN
----------------------------------------------------------------------------------
Result (cost=0.00..0.01 rows=1 width=0) (actual time=0.00..0.00 rows=1 loops=1)
Total runtime: 0.02 msec
(2 rows)
What i miss?
Thanks,
Andriy Tkachuk
http://www.imt.com.ua
---------------------------(end of broadcast)---------------------------
TIP 9: the planner will ignore your desire to choose an index scan if your
joining column's datatypes do not match
