From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Pg Hackers <pgsql-hackers@postgresql.org>
Cc: Simon Riggs <simon@2ndquadrant.com>
Subject: Re: FOR EACH ROW triggers on partitioned tables
Date: Fri, 16 Feb 2018 15:30:15 -0500
Message-ID: <812dce79-717e-6905-afee-8c3cb27aab1a@2ndquadrant.com> (raw)
In-Reply-To: <20180215215525.3anqmydfi6pfrmvf@alvherre.pgsql>
References: <20180215215525.3anqmydfi6pfrmvf@alvherre.pgsql>
On 2/15/18 16:55, Alvaro Herrera wrote:
> Amit Langote wrote:
>> Do you mean to fire these triggers only if the parent table (not a child
>> table/partition) is addressed in the DML, right? If the table directly
>> addressed in the DML is a partition whose parent has a row-level trigger,
>> then that trigger should not get fired I suppose.
>
> No, I think that would be strange and cause data inconsistencies.
> Inserting directly into the partition is seen as a performance
> optimization (compared to inserted into the partitioned table), so we
> don't get to skip firing the triggers defined on the parent because the
> behavior would become different. In other words, the performance
> optimization breaks the database.
>
> Example: suppose the trigger is used to maintain an audit record trail.
Although this situation could probably be addressed by not giving
permission to write directly into the partitions, I can't think of an
example where one would want a trigger that is only fired when writing
into the partition root rather than into the partition directly.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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To: pgsql-hackers@postgresql.org
Cc: peter.eisentraut@2ndquadrant.com, alvherre@alvh.no-ip.org, Langote_Amit_f8@lab.ntt.co.jp, robertmhaas@gmail.com, simon@2ndquadrant.com
Subject: Re: FOR EACH ROW triggers on partitioned tables
In-Reply-To: <812dce79-717e-6905-afee-8c3cb27aab1a@2ndquadrant.com>
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