Re: Index Scans become Seq Scans after VACUUM ANALYSE

On Wed, 2002-04-17 at 11:00, mlw wrote:
>
> Here is the problem, in a single paragraph.
>
> If the DBA notices that there is a problem with a query, he adds an index, he
> notices that there is no difference, then he notices that PostgreSQL is not
> using his index. First and foremost he gets mad at PostgreSQL for not using his
> index.

Perhaps a notice from backend:

NOTICE: I see the DBA has created a useless index ...

;)

Or would this make the DBA even madder ;) ;)

> If PostgreSQL decided to use an index which increases execution time,
> the DBA would delete the index. If PostgreSQL does not use an index, he has to
> modify the posgresql.conf file,

Or just do

set enable_seqscan to off;

> which disallows PostgreSQL from using an index when it would be a clear loser.
>
> My assertion is this: "If a DBA creates an index, he has a basis for his
> actions."

The basis can be that "his boss told him to" ?

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Hannu