WL#13773: Increase default group_replication_member_expel_timeout
Affects: Server-8.0 — Status: Complete
EXECUTIVE SUMMARY ================= Change the default group_replication_member_expel_timeout from 0 to 5 seconds. Currently, group_replication_member_expel_timeout is set to 0 seconds, which means that a member will expel immediately another group member which is suspected of leaving the group. Since there is a 5 second waiting period until creating the suspicion that the member has left the group, the member is actually expelled 5 seconds after becoming unreachable. If the expelled member is the primary a new primary is elected automatically. Set the default group_replication_member_expel_timeout to 5 seconds, in order to decrease the likelihood of unnecessary expulsions and primary failovers on slower networks or in the presence of transient network failures, following feedback gathered from customers. The new value for the default implies that the member will be expelled 10 seconds after becoming unreachable.
FUNCTIONAL REQUIREMENTS ======================= FR1: The default value of the variable group_replication_member_expel_timeout shall be set to 5.
Change the default value of group_replication_member_expel_timeout from '0' to '5' seconds. Run MTR and JET regression test suites with the new default value. Evaluate the list of MTR and JET tests failing. Check if these are expected due to the change in group_replication_member_expel_timeout and set it to zero for such test cases.
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