On 27/06/14 21:19, Andres Freund wrote:
On 2014-06-27 14:28:20 +1200, Mark Kirkwood wrote:
My feeling is spinlock or similar, 'perf top' shows
kernel find_busiest_group
kernel _raw_spin_lock
as the top time users.
Those don't tell that much by themselves, could you do a hierarchical
profile?
On 2014-06-27 14:28:20 +1200, Mark Kirkwood wrote:
> My feeling is spinlock or similar, 'perf top' shows
>
> kernel find_busiest_group
> kernel _raw_spin_lock
>
> as the top time users.
Those don't tell that much by themselves, could you do a hierarchical
profile? I.e. perf record -ga? That'll a
The simplified scene:
select slowfunction() from a order by b limit 1
is slow than
select slowfunction() from ( select * from a order by b limit 1)
if there are many records in table 'a'
The real scene:
function ST_Distance_Sphere is slow than ST_Distance, the query:
SELECT ST_Distance_Sphere(
