After resetting all statistics it still opts for a Seq Scan. I went ahead to test with creating another table and querying that, and it shows on that test table to be using the index. So I wonder if there is anything else that may effect the planner. is there a way I can dog into this and see the steps the planner performs while deciding which ap to use?
On 2/6/17, Podrigal, Aron <aronp@guaranteedplus.com> wrote: > Hi, > > I noticed when I do a simple SELECT id FROM mytable WHERE id = > 'cb81d070-4213-465f-b32e-b8db43b83a25'::UUID Postgres does not use the > primary key index and opts for a Seq Scan. > > I of course did VACUUM ANALYZE and I have reset statistics But no sign. Is > there any particular thing I should be looking at?
Postgres uses specified access methods according to table's statistics. If you have a small table, it is likely that Postgres uses SeqScan because it is similar or cheaper than IndexScan. That's why it can ignore existing indexes.
