Re: [GENERAL] Simple Query not using Primary Key Index

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.

--
Best regards,
Vitaly Burovoy