Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Plain View
Zookeeper >> mail # dev >> Quorum reads on zookeeper


+
Abhishek .E.S 2013-03-26, 05:37
+
Ted Dunning 2013-03-26, 08:21
+
Alexander Shraer 2013-03-26, 15:19
Copy link to this message
-
Re: Quorum reads on zookeeper
Yes.  Sure.

But Abishek's question is pretty basic so it deserved the basic answer.

On Tue, Mar 26, 2013 at 4:19 PM, Alexander Shraer <[EMAIL PROTECTED]> wrote:

> Ted, as previously discussed on this list, what you are saying is true
> when the leader doesn't fail but it may not work in the general case
> under some asynchrony conditions. Please see my email "sync semantics"
> from Mar 1st or the thread "Ensure Leader hasn't changed" from
> September 2012. In order to handle the general
> case we should make the sync a quorum operation.
>
> Alex
>
> On Tue, Mar 26, 2013 at 1:21 AM, Ted Dunning <[EMAIL PROTECTED]>
> wrote:
> > Because the leader is the one who leads all writes, it suffices to catch
> up
> > with that one node.  There is no need to read from a quorum.  Another way
> > to look at this is that there is no way for a quorum read to succeed
> > without there also existing a leader and one read to the leader is better
> > than trying to read from the entire cluster.
> >
> > On Tue, Mar 26, 2013 at 6:37 AM, Abhishek .E.S <[EMAIL PROTECTED]
> >wrote:
> >
> >> Hi,
> >>
> >> Zookeeper suggests using sync if the most up to date value is required
> for
> >> reading.
> >> Would it be possible to use Quorum reads for ensuring up to date reads ?
> >>
> >> There is a function called  isQuorum for indicating quorum requirement
> for
> >> operations. Read is listed as not requiring forum in this function
> >> How would changing this to true impact the behavior ?
> >>
> >> Any pointers would be appreciated.
> >>
> >> -Abhishek
> >>
>