On 2014-01-13 15:14:21 -0600, Jim Nasby wrote:
> On 1/13/14, 12:21 PM, Joshua D. Drake wrote:
> >
> >On 01/13/2014 10:12 AM, Hannu Krosing wrote:
> >>>>In other words, if we're going to have auto-degrade, the most
> >>>>intelligent place for it is in
> >>>>RepMgr/HandyRep/OmniPITR/pgPoolII/whatever. It's also the *easiest*
> >>>>place. Anything we do *inside* Postgres is going to have a really,
> >>>>really hard time determining when to degrade.
> >>>+1
> >>>
> >>>This is also how 2PC works, btw - the database provides the building
> >>>blocks, i.e. PREPARE and COMMIT, and leaves it to a transaction manager
> >>>to deal with issues that require a whole-cluster perspective.
> >>>
> >>
> >>++1
> >
> >+1
>
> Josh, what do you think of the upthread idea of being able to recover in-progress transactions that are waiting when
weturn off sync rep? I'm thinking that would be a very good feature to have... and it's not something you can easily do
externally.
I think it'd be a fairly simple patch to re-check the state of syncrep
config in SyncRepWaitForLsn(). Alternatively you can just write code to
iterate over the procarray and sets Proc->syncRepState to
SYNC_REP_WAIT_CANCELLED or such.
Greetings,
Andres Freund
-- Andres Freund http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services