Re: Indexing foreign keys - Mailing list pgsql-performance

From Matt Mello
Subject Re: Indexing foreign keys
Date
Msg-id 3E361946.4060000@spaceship.com
Whole thread Raw
In response to Re: Indexing foreign keys  (Ron Johnson <ron.l.johnson@cox.net>)
Responses Re: Indexing foreign keys  (Stephan Szabo <sszabo@megazone23.bigpanda.com>)
Re: Indexing foreign keys  (Ron Johnson <ron.l.johnson@cox.net>)
List pgsql-performance
Ron Johnson wrote:
> When you say "I created an index on those 2 fields", so you mean on
> the fields in the 400K row table, or on the keys in the "fact tables"
> that the 400K row table?
>
> Also, in IFX, could the creation of the foreign indexes have implicitly
> created indexes?
> The reason I ask is that this is what happens in Pg when you create a
> PK.
>

The 400K row table has 2 fields that are FK fields.  The already-indexed
PK fields that they reference are in another table.  I just recently
added indexes to the 2 FK fields in the 400K row table to get the speed
boost.

Yes.  In IFX, when you create a FK, it seems to create indexes
automatically for you, just like PG does with PK's.

In fact, I can't imagine a situation where you would NOT want a FK
indexed.  I guess there must be one, or else I'm sure the developers
would have already added auto-creation of indexes to the FK creation, as
well.

--
Matt Mello


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