Re: Support for N synchronous standby servers - take 2

On Mon, Oct 19, 2015 at 8:47 PM, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>
wrote:

>
> Hi,
>
> Attached patch is a rough patch which supports multi sync replication
> by another approach I sent before.
>
> The new GUC parameters are:
> * synchronous_standby_num, which specifies the number of standby
> servers using sync rep. (default is 0)
> * synchronous_replication_method, which specifies replication method;
> priority or quorum. (default is priority)
>
> The behaviour of 'priority' and 'quorum' are same as what we've been
> discussing.
> But I write overview of these here again here.
>
> [Priority Method]
> The standby server has each different priority, and the active standby
> servers having the top N priroity are become sync standby server.
> If synchronous_standby_names = '*', the all active standby server
> would be sync standby server.
> If you want to set up standby like 9.5 or before, you can set
> synchronous_standby_num = 1.
>
>

I used the following setting with 2 servers A and D connected:

synchronous_standby_names = 'A,B,C,D'
synchronous_standby_num = 2
synchronous_replication_method = 'priority'

Though s_r_m = 'quorum' worked fine, changing it to 'priority' caused
segmentation fault.

Regards,

Beena Emerson

Have a Great Day!