[SERVER-61557] Get rid of top chunk migration Created: 17/Nov/21 Updated: 16/May/23 Resolved: 20/Mar/23 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Sharding |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Task | Priority: | Major - P3 |
| Reporter: | Pierlauro Sciarelli | Assignee: | Pierlauro Sciarelli |
| Resolution: | Duplicate | Votes: | 0 |
| Labels: | shardingemea-qw | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Assigned Teams: |
Sharding EMEA
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| Sprint: | Sharding EMEA 2023-02-20, Sharding EMEA 2023-03-06, Sharding EMEA 2023-03-20 | ||||||||||||||||||||||||||||||||||||
| Participants: | |||||||||||||||||||||||||||||||||||||
| Story Points: | 3 | ||||||||||||||||||||||||||||||||||||
| Description |
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The top chunk migration was thought as a way to distribute the write load for applications inserting a lot of documents with non-hashed incremental shard keys. It turns out that for heavy workloads it could cause more harm than good:
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| Comments |
| Comment by Githook User [ 16/May/23 ] |
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Author: {'name': 'Pierlauro Sciarelli', 'email': 'pierlauro.sciarelli@mongodb.com', 'username': 'pierlauro'}Message: |
| Comment by Pierlauro Sciarelli [ 20/Mar/23 ] |
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Closing as duplicate of |
| Comment by Pierlauro Sciarelli [ 31/May/22 ] |
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I would keep separate tickets. We protect only the triggering of the top chunk migration flow via the feature flag, but not all code used for performing top chunk optimization is protected by the feature flag. For example, Balancer::rebalanceSingleChunk is exclusively used by top chunk optimization, but there is no reference to the feature flag. |
| Comment by Tommaso Tocci [ 31/May/22 ] |
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pierlauro.sciarelli@mongodb.com could you confirm that the entire code of the top chunk optimization will go away with the autosplitter? If so can we mark this as duplicate of the NOMAS feature flag removal |
| Comment by Kaloian Manassiev [ 18/Nov/21 ] |
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I would like to turn this into a project around improving the behaviour of bulk-loading of data into a new sharded cluster. |