[ https://issues.apache.org/jira/browse/KAFKA-7026?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Dong Lin updated KAFKA-7026: ---------------------------- Fix Version/s: (was: 2.1.0) 2.2.0 > Sticky assignor could assign a partition to multiple consumers (KIP-341) > ------------------------------------------------------------------------ > > Key: KAFKA-7026 > URL: https://issues.apache.org/jira/browse/KAFKA-7026 > Project: Kafka > Issue Type: Bug > Components: clients > Reporter: Vahid Hashemian > Assignee: Vahid Hashemian > Priority: Major > Labels: kip > Fix For: 2.2.0 > > > In the following scenario sticky assignor assigns a topic partition to two > consumers in the group: > # Create a topic {{test}} with a single partition > # Start consumer {{c1}} in group {{sticky-group}} ({{c1}} becomes group > leader and gets {{test-0}}) > # Start consumer {{c2}} in group {{sticky-group}} ({{c1}} holds onto > {{test-0}}, {{c2}} does not get any partition) > # Pause {{c1}} (e.g. using Java debugger) ({{c2}} becomes leader and takes > over {{test-0}}, {{c1}} leaves the group) > # Resume {{c1}} > At this point both {{c1}} and {{c2}} will have {{test-0}} assigned to them. > > The reason is {{c1}} still has kept its previous assignment ({{test-0}}) from > the last assignment it received from the leader (itself) and did not get the > next round of assignments (when {{c2}} became leader) because it was paused. > Both {{c1}} and {{c2}} enter the rebalance supplying {{test-0}} as their > existing assignment. The sticky assignor code does not currently check and > avoid this duplication. > > Note: This issue was originally reported on > [StackOverflow|https://stackoverflow.com/questions/50761842/kafka-stickyassignor-breaking-delivery-to-single-consumer-in-the-group]. -- This message was sent by Atlassian JIRA (v7.6.3#76005)