public inbox for [email protected]  

help / color / mirror / Atom feed

From: Alvaro Herrera <[email protected]>
To: [email protected]
To: [email protected]
Subject: Re: Add further details to ROW SHARE table level lock modes section
Date: Wed, 13 Apr 2022 20:00:49 +0200
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On 2022-Apr-04, PG Doc comments form wrote:

> I propose that it would be useful to explicitly state that `SELECT FOR KEY
> SHARE` AND `SELECT FOR NO KEY UPDATE` commands also acquire the ROW SHARE
> table level lock on target table(s). That is:
> ```
> Conflicts with the EXCLUSIVE and ACCESS EXCLUSIVE lock modes.
> 
> The SELECT FOR UPDATE, SELECT FOR NO KEY UPDATE,  SELECT FOR SHARE, and
> SELECT FOR KEY SHARE commands acquire a lock of this mode on the target
> table(s) (in addition to ACCESS SHARE locks on any other tables that are
> referenced but not selected FOR UPDATE/FOR SHARE).
> ```

I agree we need an update here.  But the original wording seems a bit
off; I think we should say SELECT is a command, and that the FOR bits
are options thereof.  Maybe something like this:

        <para>
         The <command>SELECT</command> command acquires a lock of this mode
         on all tables on which one of the <option>FOR UPDATE</option>,
         <option>FOR NO KEY UPDATE</option>,
         <option>FOR SHARE</option>, or
         <option>FOR KEY SHARE</option> options is specified
         (in addition to <literal>ACCESS SHARE</literal> locks on any other
         tables that are referenced without any explicit
         <option>FOR ...</option> locking option).
        </para>

Thoughts?

Grammar check: "one of the a,b,c options IS specified" or "one of the
a,b,c options ARE specified"?

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected]
  Subject: Re: Add further details to ROW SHARE table level lock modes section
  In-Reply-To: <[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox