I also agree that it's enough to use mzxid in the case. As you know, zxid is global value which is used to be stamped in znode as czxid, mzxid, and pzxid. It's monotonically increased even when a znode is deleted. On the other hand, the version in znode can be reset once the znode is deleted. It's the case Jordan mentioned. In conclusion, to deal with the case, we should use mzxid.
Thanks, - Tsuyoshi On Mon, Mar 13, 2017 at 7:18 AM, Scott Blum <[email protected]> wrote: > I think mxzid should be fine, it should be a ZK-wide unique value. > > On Sun, Mar 12, 2017 at 6:03 PM, Jordan Zimmerman < > [email protected]> wrote: > >> So, is mxzid enough? Do we check version too? Is compared the data even >> necessary? >> >> -JZ >> >> On Mar 12, 2017, at 2:14 PM, Scott Blum <[email protected]> wrote: >> >> Oh, this is related to CURATOR-391 https://github. >> com/apache/curator/pull/202 >> >> You wrote: >> >>> Using only Stat version to note node change (for UPDATE event) is not >>> enough. In a split brain if a node delete plus a recreate is missed, the >>> Stat version can appear to be the same. >> >> >> I never considered this corner case! So yeah, I agree that mxzid would be >> more reliable. >> >> >> On Sun, Mar 12, 2017 at 5:09 PM, Scott Blum <[email protected]> wrote: >> >>> I think "version" and "mzxid" should be equally reliable for determining >>> that the contents changed. Whenever a change happens the version gets >>> incremented while the mzxid gets set to the associated zk transaction id. >>> So I don't see a problem with ifVersion == data.getStat().getVersion() but >>> I haven't looked through all the PathChildrenCache code in a while, was >>> there something else you were referring to going on in there? >>> >>> On Sun, Mar 12, 2017 at 1:23 PM, Jordan Zimmerman < >>> [email protected]> wrote: >>> >>>> I'm working on CURATOR-391 and notice that TreeCache uses Mzxid to >>>> determine if a ZNode has changed. PathChildrenCache uses a less reliable >>>> method. I _think_ that Mzxid is enough. Does everyone else agree? >>>> >>>> -Jordan >>> >>> >>> >> >> -- - Tsuyoshi
