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Here an example of how the assignments might change as members join the share group and the number of partitions changes.
State | Members subscribed to T1 | Topic:partitions | Assignment change | Assignments |
|---|---|---|---|---|
M1 subscribed to topic T1 with 1 partition | M1 (hash 1) | T1:0 | Assign T1:0 to M1 | M1 → T1:0 |
M2 joins the group and subscribes to T1 | M1 (hash 1), M2 (hash 2) | T1:0 | Assign T1:0 to M2 | M1 → T1:0 M2 → T1:0 |
Add 3 partitions to T1 | M1 (hash 1), M2 (hash 2) | T1:0, T1:1, T1:2, T1:3 | Assign T1:1 and T1:3 to M2 Revoke T1:0 from M2 Assign T1:2 to M1 | M1 → T1:0, T1:2 M2 → T1:1, T1:3 |
M3 joins the group and subscribes to T1 | M1 (hash 1), M2 (hash 2), M3 (hash 3) | T1:0, T1:1, T1:2, T1:3 | Assign T1:2 to M3 Revoke T1:2 from M1 | M1 → T1:0 M2 → T1:1, T1:3 M3 → T1:2 |
M4 joins the group and subscribes to T1 | M1 (hash 1), M2 (hash 2), M3 (hash 3), M4 (hash 4) | T1:0, T1:1, T1:2, T1:3 | Assign T1:3 to M4 Revoke T1:3 from M2 | M1 → T1:0 M2 → T1:1 M3 → T1:2 M4 → T1:3 |
M5, M6, M7, M8 join the group and subscribe to T1 | M1 (hash 1), M2 (hash 2), M3 (hash 3), M4 (hash 4), M5 (hash 5), M6 (hash 6), M7 (hash 7), M8 (hash 8) | T1:0, T1:1, T1:2, T1:3 | Assign T1:0 to M5 Assign T1:1 to M6 Assign T1:2 to M7 Assign T1:3 to M8 | M1 → T1:0 M2 → T1:1 M3 → T1:2 M4 → T1:3 M5 → T1:0 M6 → T1:1 M7 → T1:2 M8 → T1:3 |
M1 subscribes to T2 with 2 partitions | M1 (hash 1), M2 (hash 2), M3 (hash 3), M4 (hash 4), M5 (hash 5), M6 (hash 6), M7 (hash 7), M8 (hash 8) | T1:0, T1:1, T1:2, T1:3 T2:0, T2:1 | Assign T2:0 and T2:1 to M1 | M1 → T1:0, T2:0, T2:1 M2 → T1:1 M3 → T1:2 M4 → T1:3 M5 → T1:0 M6 → T1:1 M7 → T1:2 M8 → T1:3 |
All members leave except M2 | M2 (hash 2) | T1:0, T1:1, T1:2, T1:3 | Assign T1:0, T1:2, T1:3 to M2 | M2 → T1:0, T1:1, T1:2, T1:3 |
SimpleShareAssignor does not make assignments based on rack IDs. SimpleShareAssignor does not make assignments based on lag or consumer throughput.
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| Code Block |
|---|
{
"type": "data",
"name": "ShareGroupPartitionMetadataValue",
"validVersions": "9",
"flexibleVersions": "none",
"fields": [
{ "name": "Epoch", "versions": "0+", "type": "int32" },
{ "name": "Topics", "versions": "0+", "type": "[]TopicMetadata", "fields": [ },
{ "name": "TopicIdInitializingTopics", "versions": "0+", "type": "uuid[]TopicIndexMetadata" },
{ "name": "NumPartitionsDeletingTopics", "versions": "0+", "type": "int32[]TopicMetadata" }
],
]},"commonStructs": [
{ "name": "InitializingTopicsTopicMetadata", "versions": "0+", "type": "[]TopicMetadata", "fields": [
{ "name": "TopicId", "type": "uuid", "versions": "0+",
"typeabout": "uuidThe topic identifier." },
{ {"name": "NumPartitions", "nametype": "StartPartitionIndexint32", "versions": "0+",
"typeabout": "int32The number of partitions." }
]},
{ "name": "EndPartitionIndexTopicIndexMetadata", "versions": "0+", "typefields": "int32" }[
]},
{ "name": "DeletingTopicsTopicId", "versions": "0+", "type": "[]TopicMetadatauuid", "fields": [ },
{ "name": "TopicIdStartPartitionIndex", "versions": "0+", "type": "uuidint32" },
{ "name": "NumPartitionsEndPartitionIndex", "versions": "0+", "type": "int32" }
]}
]
} |
The InitializingTopics field is used as the first stage of a two-stage process to initialize the persistent state for a set of share-partitions. When the share coordinator successfully responds to InitializeShareGroupState , the topic-partitions are moved into the Topics field.
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