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Diffstat (limited to 'weed/mq/pub_balancer/balance_action_split.go')
| -rw-r--r-- | weed/mq/pub_balancer/balance_action_split.go | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/weed/mq/pub_balancer/balance_action_split.go b/weed/mq/pub_balancer/balance_action_split.go new file mode 100644 index 000000000..6d317ffb9 --- /dev/null +++ b/weed/mq/pub_balancer/balance_action_split.go @@ -0,0 +1,43 @@ +package pub_balancer + +/* +Sequence of operations to ensure ordering + +Assuming Publisher P10 is publishing to Topic Partition TP10, and Subscriber S10 is subscribing to Topic TP10. +After splitting Topic TP10 into Topic Partition TP11 and Topic Partition TP21, +Publisher P11 is publishing to Topic Partition TP11, and Publisher P21 is publishing to Topic Partition TP21. +Subscriber S12 is subscribing to Topic Partition TP11, and Subscriber S21 is subscribing to Topic Partition TP21. + +(The last digit is ephoch generation number, which is increasing when the topic partitioning is changed.) + +The diagram is as follows: +P10 -> TP10 -> S10 + || + \/ +P11 -> TP11 -> S11 +P21 -> TP21 -> S21 + +The following is the sequence of events: +1. Create Topic Partition TP11 and TP21 +2. Close Publisher(s) P10 +3. Close Subscriber(s) S10 +4. Close Topic Partition TP10 +5. Start Publisher P11, P21 +6. Start Subscriber S11, S21 + +The dependency is as follows: + 2 => 3 => 4 + | | + v v + 1 => (5 | 6) + +And also: +2 => 5 +3 => 6 + +For brokers: +1. Close all publishers for a topic partition +2. Close all subscribers for a topic partition +3. Close the topic partition + +*/ |