UNICAST3: create receiver table when non-first message is received first ------------------------------------------------------------------------ Key: JGRP-2327 URL: https://issues.jboss.org/browse/JGRP-2327 Project: JGroups Issue Type: Enhancement Reporter: Bela Ban Assignee: Bela Ban Priority: Major Fix For: 4.0.17 * A and B * B sends 2 messages to A: B1 and B2 * A receives B2 _before_ B1 (both B1 and B2 are OOB) * The current code has A drop B2 and send a SEND_FIRST_SEQNO message to B * B resends B1, but _not_ B2 * Retransmission needs to kick in before A receives B2. This might take up to {{xmit_interval * 2}} ms before B2 is retransmitted and delivered h4. Scenario (JGRP-2293): * A installs a new view * B sends a LEAVE-REQ to A (B is leaving, too) on the view installation and a VIEW-ACK for the view. Both messages are unicasts to A and OOB * The VIEW-ACK (B2) is received first and dropped, so it will have to be retransmitted * This delays the view installation, as A waits for {{view_ack_collection_timeout}} ms until it has received all VIEW-ACKs h4. Workaround * Set GMS.leave_timeout to a higher value (say 8000ms) h4. Solution * When B2 is received, and it is not the first message and we don't have a receiver table for B yet, investigate whether we can create the receiver table anyway * However, this requires the first seqno from B *to always be 0* --> Investigate whether the first seqno in UNICAST3 is always 0, then this solution will work