From: | Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com> |
---|---|
To: | Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | "SELECT *" vs hidden columns and logical column order |
Date: | 2017-06-29 03:52:10 |
Message-ID: | CAEepm=3ZHh=p0nEEnVbs1Dig_UShPzHUcMNAqvDQUgYgcDo-pA@mail.gmail.com |
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Lists: | pgsql-hackers |
Hi hackers,
I am aware of at three potential projects that would change the
meaning of "SELECT *":
1. Incremental MATERIALIZED VIEW maintenance probably needs to be
able to use a hidden counter column which you can ask for by name but
will otherwise not show up to users:
https://www.postgresql.org/message-id/1371480075.55528.YahooMailNeo@web162901.mail.bf1.yahoo.com
2. SQL:2011 temporal tables track system time and/or valid time with
columns that users create and then declare to be temporal control
columns. I don't think they show up unless you name them directly (I
didn't check the standard but I noticed that it's that way in another
product), so I guess that's basically the same as (1).
3. Logical column order aka ALTER COLUMN POSITION, a recurring topic
on pgsql-hackers for which patches have been written but nothing has
so far managed to stick:
https://www.postgresql.org/message-id/flat/20141209174146.GP1768%40alvh.no-ip.org
Suppose someone wanted to chip away at a small piece of incremental
matviews by inventing a way to declare 'hidden' columns: is there
really a dependency here as implied in the 2013 email above? Is
anyone planning to revive logical column order?
--
Thomas Munro
http://www.enterprisedb.com
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