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Sijie Guo edited comment on BOOKKEEPER-252 at 6/11/12 5:51 AM: --------------------------------------------------------------- attach a patch based on latest trunk. the patch is generated based on BOOKKEEPER-191. was (Author: hustlmsp): attach a patch based on latest trunk. > Hedwig: provide a subscription mode to kill other subscription channel when > hedwig client is used as a proxy-style server. > -------------------------------------------------------------------------------------------------------------------------- > > Key: BOOKKEEPER-252 > URL: https://issues.apache.org/jira/browse/BOOKKEEPER-252 > Project: Bookkeeper > Issue Type: New Feature > Affects Versions: 4.1.0 > Reporter: Sijie Guo > Assignee: Sijie Guo > Fix For: 4.2.0 > > Attachments: BK-252.diff, BOOKKEEPER-252.diff > > > In some case, we need to hedwig-client as proxy server to provide messaging > service to other users. > client -> proxy server 1 -> hedwig > \> proxy server 2 /> > when client would connect to either proxy server to receive messages, the > proxy server would setup subscription channel to hedwig server. > we just want client to be simple, so when the channel between client and > proxy server is broken, client will try to connect to proxy servers thru VIP. > it might connect to other proxy server. for example, first time client > connects to proxy server 1, but the client found the connection is broken, it > connects to proxy server 2. when proxy server 2 tried to setup subscription > channel to hedwig, hedwig found that this subscription has existed before > occupied by proxy server 1. > the panic here is that proxy server 1 only disconnect old subscription > channel only when it detected the channel between client and itself is > broken. The detection might be delayed due to several reasons. so it might > increment the latency that messages are pushed to real client. > so we try to introduce a subscription mode called CREATE_OR_ATTACH_OR_KILL > mode. > when a subscriber use this subscription mode, it would kill old existed > subscription channel. when using this subscription mode, we would turn off > auto-reconnect functionality in hedwig client and just tell client about the > channel disconnected event so client could do its logic when channel is > detected. > in order to provide some admin tool for admin guys to debug/operate, we > provide ADMIN mode. if a subscriber attach to a subscription using ADMIN > mode, its subscription channel would never be killed, then it is safe to > guarantee admin operations. > -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira