Re: [HACKERS] [PATCH] Lockable views - Mailing list pgsql-hackers

From Robert Haas
Subject Re: [HACKERS] [PATCH] Lockable views
Date
Msg-id CA+Tgmob7z0e9rgCzP1D365YkjCxXb-1Zo0og4V5psc3nvfh9sQ@mail.gmail.com
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In response to Re: [HACKERS] [PATCH] Lockable views  (Thomas Munro <thomas.munro@enterprisedb.com>)
Responses Re: [HACKERS] [PATCH] Lockable views  (Tatsuo Ishii <ishii@sraoss.co.jp>)
List pgsql-hackers
On Tue, Jan 30, 2018 at 1:21 AM, Thomas Munro
<thomas.munro@enterprisedb.com> wrote:
> About the idea:  it makes some kind of sense to me that we should lock
> the underlying table, in all the same cases that you could do DML on
> the view automatically.  I wonder if this is a problem for the
> soundness:  "Tables appearing in a subquery are ignored and not
> locked."

Yeah, that seems like a pretty bad idea.  It's exposing what is
basically an implementation detail to users.  I think that if we
change the rules for which subqueries get flattened in a future
release, then the behavior will also change.  That seems bad.

I also think that this is a bad idea for another reason, which is that
it leaves us with no syntax to say that you want to lock the view
itself, and pg_dump wants do that if only we had syntax for it.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


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