2010/11/25 pasman pasmański <pasma...@gmail.com>: >>I've seen this as well be a performance issue, in particular with partitioned >>tables. >>Out of habit I now write functions that always cache the value of the >>function in >>a variable and use the variable in the actual query to avoid this particular >>"gotcha". > > subquery may be used to cache constants: > > SELECT a_date > FROM test > WHERE a_date=(SELECT current_date); > > > "Seq Scan on test1 (cost=0.01..10.76 rows=5 width=4)" > " Filter: (a_date = $0)" > " InitPlan 1 (returns $0)" > " -> Result (cost=0.00..0.01 rows=1 width=0)"
Interesting. So we pull a subquery out and treat it as an initplan, but not a stable function? Hmm... -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
