> And, to give you a starting point: the discussion has morphed into:
> "What manual ways can we come up with for the DBA to
> influence the planner and fix planner "bugs" which won't have
> the fragility of query-based hints ala Oracle?"
I see a few downsides though:
1. it lacks a way to try out different plans in one session
without actually influencing other sessions.
Maybe the way to do this is:
begin work;
add statistics hints
explain analyze your select
rollback work;
this is not enough to try a whole program with a new manual correction
though.
2. To try out sensible plans would only work if there where ways that
allow all
nodetypes (on specific tables/where clauses) to be made more/less
expensive individually.
3. the manual entry may negatively influence other queries that
previously were fast
thus a typical tuning measure for one bad query plan imposes
high risk
4. sometimes I know as a developer that certain queries only run in case
of
abnormal skew in data (e.g. I expect to get a lot of rows even if
usually i would get few)
Andreas
---------------------------(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
