Re: [infinispan-dev] Meaning of locking in Infinispan: ISPN-1546 and better general throughput
On 7 December 2011 16:00, Vladimir Blagojevic <vblagoje(a)redhat.com> wrote:
On 11-12-07 10:27 AM, Sanne Grinovero wrote:
>
>
> To solve ISPN-1546, I think it's totally fine to acquire a lock on the
> FGAM for the time needed to create an iterator. But this lock needs to
> be a different instance than the entry itself, and will be very short
> lived, and not clustered in any way. it's just a means to guarantee we
> can make a safe copy of the needed Array, and acquiring this lock
> should have nothing to do with the "data experience" of preventing
> some entries of the FGAM to be updated.
>
> thoughts?
>
In order to make these snapshot in case of FGAM I believe we need
hierarchical locks. Besides each key in FGAM having its own lock we'd now
need a lock for the entire FGAM. Do you agree?
Yes that's my thought as well, and this additional lock will not be
acquired for longer than what you need to make a consistent snapshot
- so it won't span multiple RPC requests for example, and will always
be very short so that it doesn't affect the "experienced semantics" of
the FGAM.
Sanne