Re: Why does Postgres allow duplicate (FK) constraints - Mailing list pgsql-general

From Thomas Kellerer
Subject Re: Why does Postgres allow duplicate (FK) constraints
Date
Msg-id kiuc18$9s$2@ger.gmane.org
Whole thread Raw
In response to Re: Why does Postgres allow duplicate (FK) constraints  (Alban Hertroys <haramrae@gmail.com>)
Responses Re: Why does Postgres allow duplicate (FK) constraints
List pgsql-general
Alban Hertroys, 26.03.2013 17:17:
> It can make sense during a maintenance window, if you create a new
> (redundant) FK constraint concurrently to replace the existing one.
> If you'd first remove the existing constraint, you're allowing FK
> violations until the new constraint has finished creating its index.
>
> This happens for example if you want to use a different index
> algorithm, say a gist index instead of a btree index, or if the
> initial index has gotten corrupt somehow and it needs reindexing.

I can understand this for indexes, but a foreign key constraint does not create one.

Regards
Thomas



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