Re: select query does not pick up the right index

On Thu, 10 Jan 2019 at 01:55, Abadie Lana <Lana.Abadie@iter.org> wrote:
> The other query suggested by D.Rowley has the same issue : still swap activity is higher.
> explain analyze select 'BUIL-B36-VA-RT-RT1:CL0001-2-ABW',
c.smpl_time,c.nanosecs,c.float_val,c.num_val,c.str_val,c.datatype,c.array_valfrom sample c where c.channel_id in
(selectchannel_id from channel where name ='BUIL-B36-VA-RT-RT1:CL0001-2-ABW')   order by c.smpl_time  desc limit 5; 

This is not the query I suggested.  I mentioned if channel.name had a
unique index, you'd be able to do WHERE c.channel_id = (select
channel_id from channel where name = '...').  That's pretty different
to what you have above.

--
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services