| Lists: | pgsql-hackers |
|---|
| From: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
|---|---|
| To: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
| Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Hot standby, freezing |
| Date: | 2009-11-11 10:35:50 |
| Message-ID: | 4AFA9386.5040901@enterprisedb.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Lists: | pgsql-hackers |
While reading through the patch for what must be the 100th time by now,
it occurred to me that this comment in heap_xlog_freeze:
+ /*
+ * Freezing tuples does not require conflict processing
+ */
is plain wrong. In the master, we can freeze the xmin of a tuple that's
not yet visible to all read-only transactions in the standby. We do need
conflict processing there.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
| From: | Simon Riggs <simon(at)2ndQuadrant(dot)com> |
|---|---|
| To: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
| Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Hot standby, freezing |
| Date: | 2009-11-11 15:07:53 |
| Message-ID: | 1257952073.5363.1594.camel@ebony |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Lists: | pgsql-hackers |
On Wed, 2009-11-11 at 12:35 +0200, Heikki Linnakangas wrote:
> While reading through the patch for what must be the 100th time by now,
:-)
> it occurred to me that this comment in heap_xlog_freeze:
>
> + /*
> + * Freezing tuples does not require conflict processing
> + */
>
> is plain wrong. In the master, we can freeze the xmin of a tuple that's
> not yet visible to all read-only transactions in the standby. We do need
> conflict processing there.
I agree. Hmph, I wonder why I thought otherwise?
--
Simon Riggs www.2ndQuadrant.com