Hi Kevin,
thanks for the suggestion. It was my 1st task to try this after Easter. :)
Sorry to say this parameter doesn't help:
bad planning:
set cpu_tuple_cost = '0.05';
set effective_cache_size to '6GB';
1622ms
http://explain.depesz.com/s/vuOor
set cpu_tuple_cost = '0.01';
set effective_cache_size to '6GB';
1634ms
http://explain.depesz.com/s/YqSgood planning:
set effective_cache_size to '32MB';
set cpu_tuple_cost = '0.05';
22ms
http://explain.depesz.com/s/521or
set effective_cache_size to '32MB';
set cpu_tuple_cost = '0.01';
12ms
http://explain.depesz.com/s/Ypcthis was the query:
select distinct product_code from product p_
inner join product_parent par_ on p_.parent_id=par_.id
where par_.parent_name like 'aa%' limit 2
Any idea?
Thanks in advance,
Istvan
2012/4/5 Kevin Grittner
<Kevin.Grittner@wicourts.gov>> If effective_cache_size has a greater value (6GB), this select has
> a bad planning and long query time (2000ms):
Could you try that configuration with one change and let us know how
it goes?:
set cpu_tuple_cost = '0.05';
I've seen an awful lot of queries benefit from a higher value for
that setting, and I'm starting to think a change to that default is
in order.
-Kevin