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From: scott ribe <scott_ribe@elevated-dev.com>
To: pgsql-admin@postgresql.org, pgsql-general General <pgsql-general@postgresql.org>
Subject: Re: Ideas to deal with table corruption
Date: Sat, 6 Jan 2018 12:14:56 -0700
Message-ID: <D61E7ACB-FF21-4447-8580-AC27E3DD10B2@elevated-dev.com> (raw)
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On Jan 6, 2018, at 12:11 PM, Corey Taylor <corey.taylor.fl@gmail.com> wrote:
> Is it possible for an index to not exist on those columns?
> 
> https://www.postgresql.org/docs/current/static/ddl-constraints.html#DDL-CONSTRAINTS-FK
> 
> "A foreign key must reference columns that either are a primary key or form a unique constraint. This means that the referenced columns always have an index (the one underlying the primary key or unique constraint); so checks on whether a referencing row has a match will be efficient."

One should also remember that the foreign key itself should usually be indexed, lest a delete on the referenced table require a table scan on the referencing table.

--
Scott Ribe
https://www.linkedin.com/in/scottribe/
(303) 722-0567





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