Date: Thu, 6 Feb 2020 19:05:25 -0300
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Jehan-Guillaume de Rorthais <jgdr@dalibo.com>
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: FK violation in partitioned table after truncating a referenced
 partition
Message-ID: <20200206220525.GA31831@alvherre.pgsql>
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On 2020-Feb-06, Alvaro Herrera wrote:

> Also, I think we should patch the documentation like this, because this
> effect is not 100% obvious.  (For example, if the partition strategy is
> identical in both referenced and referencing tables, you would wish that
> only the equivalent partition is truncated.  However, I doubt this can
> be really implemented.)

And of course, I forgot to attach the file.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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diff --git a/doc/src/sgml/ref/truncate.sgml b/doc/src/sgml/ref/truncate.sgml
index c1e42376ab..0895fd17eb 100644
--- a/doc/src/sgml/ref/truncate.sgml
+++ b/doc/src/sgml/ref/truncate.sgml
@@ -123,7 +123,9 @@ TRUNCATE [ TABLE ] [ ONLY ] <replaceable class="parameter">name</replaceable> [
    scans, and the whole point is not to do one.  The <literal>CASCADE</literal>
    option can be used to automatically include all dependent tables &mdash;
    but be very careful when using this option, or else you might lose data you
-   did not intend to!
+   did not intend to!  Note in particular that when the table to be truncated
+   is a partition, cascading occurs as if the parent partitioned table is
+   truncated.
   </para>
 
   <para>

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