[FIXED] Clustering: restore snapshot with some messages no longer avail #835
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When a snapshot is performed prior to messages being removed (either expired or remove due to count/size limits), a node that would restore from this snapshot would ask the leader to send messages which indexes (first/last) are in the snapshot. Both leader and node would stop the restore when the first unavail message was found. Resolves #834 Signed-off-by: Ivan Kozlovic <ivan@synadia.com>
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PR #835 fixed an issue with restoreMsgsFromSnapshot when there were unavailable messages (expired or removed due to limits). However, the implementation was not optimized when lots of messages are no longer available. Also, it would not be backward compatible with older servers. This change detects if two servers are 0.14.1+ and can then send the first available sequence if the leader does not find the requested message. With this code change, a follower that requests messages to a leader that is of previous version will handle unavailable messages in an optimized way. It will first send few requests starting at the next sequence but then will try to do a binary search but first ask the leader for the last message on its range. If this message is not found, then that means all messages in the range have expired. After several releases, when we deem reasonable that all servers should be at 0.14.2+, we could remove some of the complexity in this PR. Resolves #834 Signed-off-by: Ivan Kozlovic <ivan@synadia.com>
kozlovic
added a commit
that referenced
this pull request
May 21, 2019
PR #835 fixed an issue with restoreMsgsFromSnapshot when there were unavailable messages (expired or removed due to limits). However, the implementation was not optimized when lots of messages are no longer available. Also, it would not be backward compatible with older servers. This change detects if two servers are 0.14.1+ and can then send the first available sequence if the leader does not find the requested message. With this code change, a follower that requests messages to a leader that is of previous version will handle unavailable messages in an optimized way. It will first send few requests starting at the next sequence but then will try to do a binary search but first ask the leader for the last message on its range. If this message is not found, then that means all messages in the range have expired. After several releases, when we deem reasonable that all servers should be at 0.14.2+, we could remove some of the complexity in this PR. Resolves #834 Signed-off-by: Ivan Kozlovic <ivan@synadia.com>
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When a snapshot is performed prior to messages being removed (either
expired or remove due to count/size limits), a node that would
restore from this snapshot would ask the leader to send messages
which indexes (first/last) are in the snapshot.
Both leader and node would stop the restore when the first unavail
message was found.
Resolves #834
Signed-off-by: Ivan Kozlovic ivan@synadia.com