> I've changed default_statistics_target to 1 and I think that is a
> reason.
> That's certainly going to cost you something, but this seems like a mighty
large slowdown, especially for a non-join query. What datatype is te.idtr,
anyway?
Integer not null and primary key of t_positions tab
=?iso-8859-2?Q?Artur_Zaj=B1c?= writes:
> I've changed default_statistics_target to 1 and I think that is a
> reason.
That's certainly going to cost you something, but this seems like a
mighty large slowdown, especially for a non-join query. What datatype
is te.idtr, anyway?
2010/11/15 Artur Zając :
> Why there is so big difference between explain analyze (0.710 ms) and
> real execution time (3309 ms)? Any suggestions?
> Could it be that it takes a long time to plan for some reason? How fast
is a plain EXPLAIN?
Yes! That is it :) Planning is painful. I'm so stupi
2010/11/15 Artur Zając :
> Why there is so big difference between explain analyze (0.710 ms) and real
> execution time (3309 ms)? Any suggestions?
Could it be that it takes a long time to plan for some reason? How
fast is a plain EXPLAIN?
What happens if you start up psql, turn on \timing, and t
[Tom Lane]
> EXPLAIN ANALYZE doesn't account for all of the runtime involved. In
> this case, I'd bet that session startup/shutdown is a big part of the
> difference.
The session startup/shutdown should be the same for the real SQL and
the broken SQL, shouldn't it?
[Artur Zając]
> time psql -c
> EXPLAIN ANALYZE doesn't account for all of the runtime involved. In this
case, I'd bet that session startup/shutdown is a big part of the difference.
>
> regards, tom lane
Does session startup/shutdown depend on tables used in query? Some simpler
query:
time psql -c 'e
=?iso-8859-2?Q?Artur_Zaj=B1c?= writes:
> Why there is so big difference between explain analyze (0.710 ms) and real
> execution time (3309 ms)?
EXPLAIN ANALYZE doesn't account for all of the runtime involved. In
this case, I'd bet that session startup/shutdown is a big part of the
difference.
I have some simple query (executed with time command):
time psql -c 'explain analyze SELECT te.idt FROM t_positions AS te JOIN
t_st AS stm ON (te.idt=stm.idt AND 4=stm.idm) WHERE te.idtr IN (347186)'
QUERY
PLAN
