FYI - I’ve applied the last remaining request from Review Board and moved the patch to Github:
https://github.com/apache/zookeeper/pull/82 -Jordan > On Aug 30, 2016, at 7:27 PM, Jordan Zimmerman <jor...@jordanzimmerman.com> > wrote: > >> As I understand TTL nodes, you want to have them when you don't want to have >> sessions > > That’s not the only use case. For example, here at Elasticsearch we have a > need for a semi-persistent node. It’s a node that lasts for about an hour. > Whether or not there is a session is irrelevant. I ended up adding a recipe > to Curator for it but it would be much nicer to have direct support in ZK for > this. Again, I think you’re conflating the session issue with TTL nodes. They > are different topics. > > -Jordan > >> On Aug 30, 2016, at 12:23 PM, Flavio Junqueira <f...@apache.org> wrote: >> >> As I understand TTL nodes, you want to have them when you don't want to have >> sessions. I find it odd that you still need to create a session when you >> choose to use TTL nodes to avoid sessions. It is correct that you can create >> session/create TTL/close session in this order, but again, if you're trying >> to avoid sessions, then it doesn't seem to be very appealing to use TTL >> nodes this way. >> >> In any case, I need to go through the e-mail thread that Camille pointed >> out. There is possibly some insight there that I'm missing. >> >> -Flavio >> >>> On 30 Aug 2016, at 14:21, Jordan Zimmerman <jor...@jordanzimmerman.com> >>> wrote: >>> >>> Yes, you need a session to create the TTL node. I believe discussion about >>> needing a session to create the node is beyond the scope of this issue and >>> should be addressed by a new Jira issue. It doesn’t affect the utility of >>> TTL nodes that you must first have a ZK session. Users who no longer want a >>> session can merely close the ZK handle after creating the TTL node. >>> >>> -Jordan >>> >>>> On Aug 30, 2016, at 7:41 AM, Flavio Junqueira <f...@apache.org> wrote: >>>> >>>> >>>>> On 29 Aug 2016, at 19:51, Jordan Zimmerman <jor...@jordanzimmerman.com> >>>>> wrote: >>>>> >>>>>> On the server side, we already have a mechanism to expire sessions, do >>>>>> we a separate scheme to expire TTL nodes or can we use the same >>>>>> mechanism? Does it make sense to consider a TTL node as a degenerate >>>>>> case of a session in which I have a single ephemeral node? My >>>>>> recollection is that it currently uses the container manager instead. >>>>> >>>>> The TTL implementation I did takes advantage of the Container node >>>>> feature. A TTL node is a variation of a container node. It doesn’t >>>>> require a session (like any persistent node). >>>>> >>>> >>>> It doesn't require a session, but the client has no way to create such a >>>> TTL node without creating a session first, right? You need the zk handle, >>>> which has a session associated, to create a TTL node as I understand it. >>>> >>>> -Flavio >>>> >>> >>> >> >
