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

From Thomas Munro
Subject Re: [HACKERS] [PATCH] Lockable views
Date
Msg-id CAEepm=3ww6sFeKrvNOfaMTES-F-FPirvAr_GwVTZcZTGXNdJXg@mail.gmail.com
Whole thread Raw
In response to Re: [HACKERS] [PATCH] Lockable views  (Tatsuo Ishii <ishii@sraoss.co.jp>)
Responses Re: [HACKERS] [PATCH] Lockable views
Re: [HACKERS] [PATCH] Lockable views
List pgsql-hackers
On Tue, Jan 30, 2018 at 6:48 PM, Tatsuo Ishii <ishii@sraoss.co.jp> wrote:
>>> You need to DROP VIEW lock_view4 and lock_view5 in the regression
>>> test as well.
>>
>> Thank you for reviewing the patch.
>>
>> I fixed this and attached a updated patch v6.
>
> Looks good to me. If there's no objection, especially from Thomas
> Munro, I will mark this as "ready for committer".

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."  I can imagine using this for making backwards-compatible
schema changes, in which case the LOCK-based transaction isolation
techniques might benefit from this behaviour.  I'd be interested to
hear about the ideal use case you have in mind.

About the patch:  I didn't study it in detail.  It builds, has
documentation and passes all tests.  Would it be a good idea to add an
isolation test to show that the underlying relation is actually
locked?

Typo:

+ /* Check permissions with the view owner's priviledge. */

s/priviledge/privilege/

Grammar:

+/*
+ * Check whether the view is lockable.
+ *
+ * Currently, only auto-updatable views can be locked, that is,
+ * views whose definition are simple and that doesn't have
+ * instead of rules or triggers are lockable.

s/definition are simple and that doesn't/definition is simple and that don't/
s/instead of/INSTEAD OF/ ?

-- 
Thomas Munro
http://www.enterprisedb.com


pgsql-hackers by date:

Previous
From: Tatsuo Ishii
Date:
Subject: Re: [HACKERS] [PATCH] Lockable views
Next
From: Fabien COELHO
Date:
Subject: Re: PATCH: pgbench - break out timing data for initializationphases