| From: | Craig Ringer <craig(at)2ndquadrant(dot)com> |
|---|---|
| To: | "Tsunakawa, Takayuki" <tsunakawa(dot)takay(at)jp(dot)fujitsu(dot)com> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Magnus Hagander <magnus(at)hagander(dot)net>, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>, Elvis Pranskevichus <elprans(at)gmail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: [PATCH v1] Add and report the new "in_hot_standby" GUC pseudo-variable. |
| Date: | 2017-04-13 07:47:55 |
| Message-ID: | CAMsr+YGKOqx3MO83ScFAvHpzBFVseGHAh9OHa1KO39Ny42R0vg@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On 13 April 2017 at 14:59, Tsunakawa, Takayuki
<tsunakawa(dot)takay(at)jp(dot)fujitsu(dot)com> wrote:
> 2. Make transaction_read_only GUC_REPORT
> This is to avoid the added round-trip by SHOW command. It also benefits client apps that want to know when the server gets promoted? And this may simplify the libpq code.
> I don't understand yet why we need to provide this feature for older servers by using SHOW. Those who are already using <= 9.6 in production completed the system or application, and their business is running. Why would they want to just replace libpq and use this feature?
I think "transaction_read_only" is a bit confusing for something we're
expecting to change under us.
To me, a "read only" xact is one created with
BEGIN READ ONLY TRANSACTION;
.... which I would not expect to become read/write under me, since I
explicitly asked for read-only.
It's more like "session read only" that we're interested in IMO.
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Kyotaro HORIGUCHI | 2017-04-13 07:49:49 | Re: FDW and parallel execution |
| Previous Message | Andrew Borodin | 2017-04-13 07:01:46 | Re: Merge join for GiST |