Re: Replication

On 06/06/16 09:54, Masahiko Sawada wrote:
> On Sat, Jun 4, 2016 at 10:58 PM, Vik Fearing <vik(at)2ndquadrant(dot)fr> wrote:
>> On 02/06/16 15:32, Bertrand Paquet wrote:
>>> Hi,
>>>
>>> On an hot standby streaming server, is there any way to know, in SQL, to
>>> know the ip of current master ?
>>
>> No.
>>
>>> The solution I have is to read the recovery.conf file to find
>>> primary_conninfo,
>>
>> That is currently the only solution. There are plans to allow SQL
>> access to the parameters in recovery.conf (or to merge them into
>> postgresql.conf) but that's not currently possible.
>
> It might not be a right way but how about using pg_read_file()?
> postgres(1)=# select regexp_replace(pg_read_file('recovery.conf'),
> '.*primary_conninfo = (.*)', '\1');
> regexp_replace
> ---------------------------------------------------
> 'host=localhost port=5550 application_name=node1'+
>
> (1 row)
>
> You can get the master server information via SQL from standby server.

This is a good idea, but suffers the same problem that Bertrand has with
looking at the file a different way: if the file was changed but the
standby server has not been restarted, it's (potentially) not going to
be the correct information.
--
Vik Fearing +33 6 46 75 15 36
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support