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https://issues.apache.org/jira/browse/CASSANDRA-13738?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16112230#comment-16112230
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Jay Zhuang commented on CASSANDRA-13738:
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I think the problem has been there for awhile. It only happens when [the 
IndexSummary is 
rebuilt|https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/io/sstable/IndexSummaryRedistribution.java#L129],
 which is triggered by [large read traffic load 
changing|https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/io/sstable/IndexSummaryRedistribution.java#L202].
 I'm able to reproduce it with an unittest. Here is the patch, please review:
| branch | utest |
| [13738-2.2|https://github.com/cooldoger/cassandra/tree/13738-2.2] | 
[circleci#53|https://circleci.com/gh/cooldoger/cassandra/53] |
| [13738-3.0|https://github.com/cooldoger/cassandra/tree/13738-3.0] | 
[circleci#52|https://circleci.com/gh/cooldoger/cassandra/52] |
| [13738-3.11|https://github.com/cooldoger/cassandra/tree/13738-3.11] | 
[circleci#51|https://circleci.com/gh/cooldoger/cassandra/51] |
| [13738-trunk|https://github.com/cooldoger/cassandra/tree/trunk] | 
[circleci#50|https://circleci.com/gh/cooldoger/cassandra/50] |

Seems branch {{2.1}} don't have this issue.

> Load is over calculated after each IndexSummaryRedistribution
> -------------------------------------------------------------
>
>                 Key: CASSANDRA-13738
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-13738
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>            Reporter: Jay Zhuang
>            Assignee: Jay Zhuang
>             Fix For: 3.0.x, 3.11.x, 4.x
>
>         Attachments: sizeIssue.png
>
>
> For example, here is one of our cluster with about 500GB per node, but 
> {{nodetool status}} shows far more load than it actually is and keeps 
> increasing, restarting the process will reset the load, but keeps increasing 
> afterwards:
> {noformat}
> Status=Up/Down
> |/ State=Normal/Leaving/Joining/Moving
> --  Address        Load       Tokens       Owns (effective)  Host ID          
>                      Rack
> UN  IP1*****       13.52 TB   256          100.0%            
> c4c31e0a-3f01-49f7-8a22-33043737975d  rac1
> UN  IP2*****       14.25 TB   256          100.0%            
> efec4980-ec9e-4424-8a21-ce7ddaf80aa0  rac1
> UN  IP3*****       13.52 TB   256          100.0%            
> 7dbcfdfc-9c07-4b1a-a4b9-970b715ebed8  rac1
> UN  IP4*****       22.13 TB   256          100.0%            
> 8879e6c4-93e3-4cc5-b957-f999c6b9b563  rac1
> UN  IP5*****       18.02 TB   256          100.0%            
> 4a1eaf22-4a83-4736-9e1c-12f898d685fa  rac1
> UN  IP6*****       11.68 TB   256          100.0%            
> d633c591-28af-42cc-bc5e-47d1c8bcf50f  rac1
> {noformat}
> !sizeIssue.png|test!
> The root cause is if the SSTable index summary is redistributed (typically 
> executes hourly), the updated SSTable size is added again.



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