Re: Patch: Implement failover on libpq connect level.

On 19 November 2016 at 01:29, Robert Haas <robertmhaas@gmail.com> wrote:

>> We can and probably should have both.
>>
>> If the server tells us on connect whether it's a standby or not, use that.
>>
>> Otherwise, ask it.
>>
>> That way we don't pay the round-trip cost and get the log spam when
>> talking to newer servers that send us something useful in the startup
>> packet, but we can still query it on older servers. Graceful fallback.
>>
>> Every round trip is potentially very expensive. Having libpq do them
>> unnecessarily is bad.
>
> True, but raising the bar for this feature so that it doesn't get done
> is also bad.  It can be improved in a later patch.

Good point. Starting with the followup query method seems fine.


-- Craig Ringer                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services