Re: standby registration (was: is sync rep stalled?)

On Fri, Oct 8, 2010 at 4:29 AM, Yeb Havinga <yebhavinga(at)gmail(dot)com> wrote:
> Robert Haas wrote:
>>
>> Yes, let's please just implement something simple and get it
>> committed.  k = 1.  Two GUCs (synchronous_standbys = name, name, name
>> and synchronous_waitfor = none|recv|fsync|apply), SUSET so you can
>> change it per txn.  Done.  We can revise it *the day after it's
>> committed* if we agree on how.  And if we *don't* agree, then we can
>> ship it and we still win.
>>
>
> I like the idea of something simple committed first, and am trying to
> understand what's said above.
>
> k = 1 : wait for only one ack
> two gucs: does this mean configurable in postgresql.conf at the master, and
> changable with SET commands on the master depending on options? Are both
> gucs mutable?
> synchronous_standbys: I'm wondering if this registration is necessary in
> this simple setup. What are the named used for? Could they be removed?
> Should they also be configured at each standby?
> synchronous_waitfor: If configured on the master, how is it updated to the
> standbys? What does being able to configure 'none' mean? k = 0? I smell a
> POLA violation here.

Well, there's got to be some way to turn synchronous replication off.
The obvious methods are to allow synchronous_standbys to be set to
empty or to allow synchronous_waitfor to be set to none.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company