Re: Index not used in join.. (example included)

From: Ron Arts <ron(dot)arts(at)neonova(dot)nl>
To: Michael Wood <esiotrot(at)gmail(dot)com>
Cc: PostgreSQL List - Novice <pgsql-novice(at)postgresql(dot)org>
Subject: Re: Index not used in join.. (example included)
Date: 2009-09-18 13:15:15
Message-ID: 4AB387E3.7010707@neonova.nl
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Michael Wood schreef:
> 2009/9/18 Michael Wood <esiotrot(at)gmail(dot)com>:
>> 2009/9/18 Ron Arts <ron(dot)arts(at)neonova(dot)nl>:
>>> A. Kretschmer schreef:
>> [...]
>>>> You can try to force an index-scan by disabling the seq-scan (set
>>>> enable_seqscan='no';) and re-run the query.
>>> That does force it to use the index, but doesn't speed up my query.
>> Would it help to add an index on the name column of the detail table?
>> And maybe to make it a foreign key referencing the first table?
>
> Sorry, I just had another look and see you do have an index on the
> name column in detail.
>
> I wonder if it would make a difference if the index on the first table
> was a unique index.
>
> --
> Michael Wood <esiotrot(at)gmail(dot)com>
>

Well, the name columns are not unique in both tables. So I cannot make it
an unique index.

Ron

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