This seems like one of the most asked questions in the PostgreSQL world, but I
guess I haven’t understood all the answers yet:
Why won’t my SELECT query use the INDEX I have created for it?
I have a table with about 18mio rows.
My SELECT statement looks like this:
SELECT
On 12/16/2014 9:18 AM, Casper Børgesen (CABO) wrote:
This seems like one of the most asked questions in the PostgreSQL world,
but I guess I haven’t understood all the answers yet:
Why won’t my SELECT query use the INDEX I have created for it?
I have a table with about 18mio rows.
My SELECT
Hey,
no index can come from 2 problems :
- your querry can't use the index
- your querry could use the index but the planner thinks it's faster to
do sequential scan.
You can discriminate between the 2 avoiding explicitly sequential scan :
`SET enable_seqscan TO FALSE`
(don't forget to turn
For this particular case,
using st_srid(geom) means that the planner have to compute this value for
each line .
(the planner has no way to know that srid is the same for every geometry in
the column, this might not be the case)
You can't use it .
for instance, you could simply use plpgsql to get
