Re: select query does not pick up the right index - Mailing list pgsql-performance

On Wed, Jan 02, 2019 at 04:28:41PM +0000, Abadie Lana wrote:
> css_archive_3_0_0=# explain analyze select t.name, c.smpl_time,c.nanosecs,c.float_val,c.num_
                                            val,c.str_val,c.datatype,c.array_val from sample c, channel t where
t.channel_id=c.channel_i                                                                      d and
t.name='BUIL-B36-VA-RT-RT1:CL0001-2-ABW'  order by c.smpl_time desc limit 5;
 
>  QUERY PLAN
> 
> --------------------------------------------------------------------------------------------
> --------------------------------------------------------------------------------------------
> -------------
> Gather  (cost=1004.71..125606.08 rows=5 width=150) (actual time=38737.443..1220277.244 rows
> =3 loops=1)
>    Workers Planned: 1
>    Workers Launched: 1
>    Single Copy: true

Do you have force_parallel_mode set ?

http://rhaas.blogspot.com/2018/06/using-forceparallelmode-correctly.html

-- 
Justin Pryzby
System Administrator
Telsasoft
+1-952-707-8581