Add further details to ROW SHARE table level lock modes section
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/14/explicit-locking.html
Description:
The ROW SHARE table level lock modes section currently states:
```
Conflicts with the EXCLUSIVE and ACCESS EXCLUSIVE lock modes.
The SELECT FOR UPDATE and SELECT FOR 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 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).
```
Thank you for your time.
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/
Op 13-04-2022 om 20:00 schreef Alvaro Herrera:
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"?
one [...] IS specified