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[Zookeeper-developer] [ zookeeper-Patches-1845696 ] Create session patch
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From: SourceForge.net <no...@so...> - 2007-12-11 18:48:50
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Patches item #1845696, was opened at 2007-12-06 09:29 Message generated for change (Comment added) made by breed You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=1008546&aid=1845696&group_id=209147 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: server Group: None >Status: Closed >Resolution: Accepted Priority: 5 Private: No Submitted By: Benjamin Reed (breed) >Assigned to: Benjamin Reed (breed) Summary: Create session patch Initial Comment: There is a weird race condition in the quorum server where it is possible that a create session request can be committed and applied at a follower before it is applied at the leader. The problem is that the checkSession that is done in PrepRequestProcessor doesn't look at pending createRequests when checking the session. Thus, a follower can commit the createSession, submit a new request to the leader, and the pending request processor at the leader can reject the request as part of an expired session before the createSession request is applied at the leader. The simplest fix seems to be to add the new session to the sessionTable before the request is actually committed. It is premature in theory, but in practice it fixes this problem and doesn't do any damage if it is incorrect (a failure causes the session not to be committed.) ---------------------------------------------------------------------- >Comment By: Benjamin Reed (breed) Date: 2007-12-11 10:48 Message: Logged In: YES user_id=154690 Originator: YES Committed revision 64. ---------------------------------------------------------------------- Comment By: Mahadev Konar (mahadevkonar) Date: 2007-12-10 11:54 Message: Logged In: YES user_id=1926680 Originator: NO +1 the patch looks good!! ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=1008546&aid=1845696&group_id=209147 |
