Re: database not using indexes, yet

Silvio Brandani <silvio(dot)brandani(at)tech(dot)sdb(dot)it> writes:
> On postgres 8.3.11 on linux centos 5 we have a table not too big with
> primary key index on

> Indexes:
> "aida_references_pkey" PRIMARY KEY, btree (aida_reference_id)

> the query not use index:

> aidadb=# explain analyze select aida_reference_id from
> aida.aida_references where aida_reference_id = '3145';
> QUERY PLAN
> ----------------------------------------------------------------------------------------------------------------
> Seq Scan on aida_references (cost=0.00..51489.15 rows=1 width=4)
> (actual time=0.173..1457.643 rows=1 loops=1)
> Filter: (aida_reference_id = 3145)
> Total runtime: 1457.696 ms

There's nothing here to suggest that this query shouldn't use an index,
so the problem is in something you didn't show us. Maybe you have
enable_indexscan turned off, or maybe that index isn't really on that
table, or something else.

regards, tom lane