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  1. JGroups
  2. JGRP-659

Merge and UNICAST sequencing problem

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Details

    • Bug
    • Resolution: Done
    • Major
    • 2.8
    • 2.4, 2.5, 2.6
    • None

    Description

      The problem is related to trashing of connection table in UNICAST during merge. Consider following scenario:

      There are 4 nodes in a cluster A,B,C, and D. After network split we have two islands A,B and C,D. When the network healing starts eventually MergeView gets installed in both islands. MergeView installation causes trashing of UNICAST connection table [1].

      However if we have a scenario where MergeView gets installed in A,B island at time T and it gets installed in island C,D at time T+N msec and a node from island A,B sends a unicast message in this N msec time window then we'll run into problems with unicast sequencing at C and D. Why? Because next message coming from island A,B into C,D will be will with sequence number > 1 and sequencing in UNICAST of C,D after connection trashing (from merge) expects starting sequence of 1. This causes UNICAST in C and/or D to wait forever for missing messages. Final outcome is thus that no more unicast message coming from A and/or B will ever be delivered at C and/or D!

      [1]http://jira.jboss.com/jira/browse/JGRP-348

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          is blocked by

          Feature Request - Feature requests from customers and/or users JGRP-129 Logical addresses

          • Major - To be worked after higher priority work items are addressed. When the severity is high and the effort to change it is low to moderate, this term is chosen. Issues in this category likely have an existing workaround but implementation or execution may be non-trivial.
          • Resolved
          is duplicated by

          Bug - A problem that impairs or prevents the functions of the product. JGRP-952 MERGE: UNICAST can lose messages on merging

          • Major - To be worked after higher priority work items are addressed. When the severity is high and the effort to change it is low to moderate, this term is chosen. Issues in this category likely have an existing workaround but implementation or execution may be non-trivial.
          • Resolved
          is related to

          Task - Represents a small unit of work that is not end-user facing. JGRP-700 FLUSH: flushing should span merge

          • Major - To be worked after higher priority work items are addressed. When the severity is high and the effort to change it is low to moderate, this term is chosen. Issues in this category likely have an existing workaround but implementation or execution may be non-trivial.
          • Resolved
          relates to

          Bug - A problem that impairs or prevents the functions of the product. JGRP-665 Merge and Multiplexer have a race issue

          • Major - To be worked after higher priority work items are addressed. When the severity is high and the effort to change it is low to moderate, this term is chosen. Issues in this category likely have an existing workaround but implementation or execution may be non-trivial.
          • Resolved

          Task - Represents a small unit of work that is not end-user facing. JGRP-939 MERGE: merging of overlapping subgroups causes problems with UNICAST

          • Major - To be worked after higher priority work items are addressed. When the severity is high and the effort to change it is low to moderate, this term is chosen. Issues in this category likely have an existing workaround but implementation or execution may be non-trivial.
          • Resolved

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            People

              rhn-engineering-bban Bela Ban
              vblagoje Vladimir Blagojevic (Inactive)
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              Dates

                Created:
                Updated:
                Resolved: