Re: Missing docs: setting up replication slots for standbys

On 2014-09-03 22:43:19 -0700, Josh Berkus wrote:
>
> Section 46.2.2 has this:
>
> Note: PostgreSQL also has streaming replication slots (see Section
> 25.2.5), but they are used somewhat differently there.
>
> Section 25.2.5 has this:
>
> You can avoid this by setting wal_keep_segments to a value large enough
> to ensure that WAL segments are not recycled too early, or by
> configuring a replication slot for the standby.
>
> ... however, absolutely nowhere is it explained how to configure a
> replication slot for a streaming replica. Is it, in fact, possible to
> do so?

It actually is explained. I don't have a built source handy right now,
so chapter numbers... But at least the following is there:

<sect3 id="streaming-replication-slots-config">
<title>Configuration Example</title>
<para>
You can create a replication slot like this:
<programlisting>
postgres=# SELECT * FROM pg_create_physical_replication_slot('node_a_slot');
slot_name | xlog_position
-------------+---------------
node_a_slot |

postgres=# SELECT * FROM pg_replication_slots;
slot_name | slot_type | datoid | database | active | xmin | restart_lsn
-------------+-----------+--------+----------+--------+------+-------------
node_a_slot | physical | | | f | |
(1 row)
</programlisting>
To configure the standby to use this slot, <varname>primary_slot_name</>
should be configured in the standby's <filename>recovery.conf</>.
Here is a simple example:
<programlisting>
standby_mode = 'on'
primary_conninfo = 'host=192.168.1.50 port=5432 user=foo password=foopass'
primary_slot_name = 'node_a_slot'
</programlisting>

and I'm pretty sure primary_slot_name and such is configured at the
appropriate place too.

That's not to say it can't be be expanded and/or better linked...

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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