On Tue, Nov 25, 2008 at 7:16 PM, Jan Luehe <Jan.Luehe_at_sun.com> wrote:
> Hi Dick,
>
> On 11/25/08 07:26 AM, Dick Davies wrote:
>
> On Tue, Nov 25, 2008 at 6:05 AM, Shreedhar Ganapathy
> <Shreedhar.Ganapathy_at_sun.com> wrote:
>
>
> Ah, hadn't realised that; assumed session replication piggybacked on
> GMS traffic.
>
> Does that mean sessions do not go over multicast?
>
>
>
> Sessions go over TCP when replication happens. Replication module does need
> multicast to send out a query to the group as to who owns a particular
> version of a given session. This typically happens during failover.
>
>
> Thanks Shreedhar
>
> so just to clarify; when an instance gets a http request with a
> session it does not
> have the latest version of (determined by JSESSIONIDVERSION), it sends
> out a multicast
> request for it?
>
>
> [1] Yes, but only after checking its replica cache to see if it contains
> the session with the requested JSESSIONID and JSESSIONIDVERSION.
> If found, it will activate its replica copy of the requested session, and no
> multicast
> will be sent out. Otherwise, a multicast will be sent.
>
> i.e. rather than instances pushing out sessions to their cluster
> peers, a server requests a session if it needs it and does not have it
> locally?
>
>
> After having served a session (from its active cache), an instance will push
> a replica
> copy of the session (with incremented JSESSIONIDVERSION) to its replication
> partner instance only, to enable [1].
Thanks, that makes sense.
The logs I posted today seem to show the instance
checking it's replica cache for the session its presented with
(40b0e381597bc46a42826ccc239e) and then asking the other instance for it,
so it does look like something may be screwed with our replication layer:
[#|2008-11-25T14:35:00.192+0000|INFO|sun-appserver9.1|com.sun.enterprise.ee.web.sessmgmt|_ThreadID=21;_ThreadName=httpSSLWorkerThread-38080-18;|transferFromReplicationCache
for id: 40b0e381597bc46a42826ccc239e took: 0 ms|#]
[#|2008-11-25T14:35:00.193+0000|INFO|sun-appserver9.1|com.sun.enterprise.ee.web.sessmgmt|_ThreadID=21;_ThreadName=httpSSLWorkerThread-38080-18;|ReplicationStore>>load:localCachedState=null|#]
[#|2008-11-25T14:35:00.193+0000|INFO|sun-appserver9.1|javax.enterprise.system.stream.out|_ThreadID=21;_ThreadName=httpSSLWorkerThread-38080-18;|TEST:load
called during reshape|#]
[#|2008-11-25T14:35:04.200+0000|INFO|sun-appserver9.1|com.sun.enterprise.ee.web.sessmgmt|_ThreadID=21;_ThreadName=httpSSLWorkerThread-38080-18;|findSessionViaBroadcast
for id: 40b0e381597bc46a42826ccc239e took: 4007 ms|#]