Re: Why there are no max_wal_receivers

Hello:

Thank you all for kindly replying my question.

I read the documentation about pg_basebackup.

The description says:

The server must also be configured with max_wal_senders set high enough to
leave at least one session available for the backup.

Dose it mean:

If I am building a one master -- one slave environment, I need the
max_wal_sender to be at least 2.

But I think pg_basebackup just use the one sender process temporarily, Is
that right?

Best Regards

2013/10/7 Adrian Klaver <adrian(dot)klaver(at)gmail(dot)com>

> On 10/06/2013 09:53 PM, Amit Langote wrote:
>
>> Hi,
>>
>> On Mon, Oct 7, 2013 at 12:02 PM, 高健 <luckyjackgao(at)gmail(dot)com> wrote:
>>
>>> Hello :
>>>
>>>
>>> I found that for PG9.2.4, there is parameter max_wal_senders,
>>>
>>> But there is no parameter of max_wal_receivers.
>>>
>>>
>>>
>> max_wal_senders is the maximum number of WAL sender processes that a
>> primary server can create in response to requests from the standby
>> servers. One WAL sender process is created on the primary server for
>> each standby which would running the corresponding WAL receiver. So
>> there is one-to-one mapping between WAL senders and WAL receivers
>> (standbys).
>>
>
> Just to add, pg_basebackup also counts against the total of receivers:
>
> http://www.postgresql.org/**docs/9.3/interactive/app-**pgbasebackup.html<http://www.postgresql.org/docs/9.3/interactive/app-pgbasebackup.html>
>
>
>
>> --
>> Amit Langote
>>
>>
>>
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)gmail(dot)com
>