| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
| Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Predicate Locks for writes? |
| Date: | 2017-10-11 16:27:51 |
| Message-ID: | CA+TgmoYtmeb3wG0-=0B+OZp6fWnMH8BePkACErejFo+84_GFwA@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Wed, Oct 11, 2017 at 11:51 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> I'm inclined to believe Robert's hypothesis that there is some race
> condition there.
>
> The question is whether that still constitutes a serializability
> problem since we haven't done anything with the data, just passed it
> upwards to be modified.
Well, the question is whether passing it upwards constitutes reading
it. I kind of suspect it does. The plan tree isn't just blindly
propagating values upward but stuff with them. There could be quite a
bit between the ModifyTable node and the underlying scan if DELETE ..
FROM or UPDATE .. USING is in use.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2017-10-11 16:32:20 | Re: [COMMITTERS] pgsql: Add port/strnlen support to libpq and ecpg Makefiles. |
| Previous Message | Andres Freund | 2017-10-11 16:12:18 | Re: pgsql: Add port/strnlen support to libpq and ecpg Makefiles. |