On 01/10/2014 01:49 PM, Andres Freund wrote:
> On 2014-01-10 10:59:23 -0800, Joshua D. Drake wrote:
>>
>> On 01/10/2014 07:47 AM, Bruce Momjian wrote:
>>
>>> I know there was a desire to remove this TODO item, but I think we have
>>> brought up enough new issues that we can keep it to see if we can come
>>> up with a solution. I have added a link to this discussion on the TODO
>>> item.
>>>
>>> I think we will need at least four new GUC variables:
>>>
>>> * timeout control for degraded mode
>>> * command to run during switch to degraded mode
>>> * command to run during switch from degraded mode
>>> * read-only variable to report degraded mode
I would argue that we don't need the first. We just want a command to
switch synchronous/degraded, and a variable (or function) to report on
degraded mode. If we have those things, then it becomes completely
possible to have an external monitoring framework, which is capable of
answering questions like "is the replica down or just slow?", control
degrade.
Oh, wait! We DO have such a command. It's called ALTER SYSTEM SET!
Recently committed. So this is really a solvable issue if one is
willing to use an external utility.
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com