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https://issues.apache.org/jira/browse/CASSANDRA-21632?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Brandon Williams reassigned CASSANDRA-21632:
--------------------------------------------

    Assignee: Alexandre Viau  (was: Brandon Williams)

> BTI partition index preload is unbounded
> ----------------------------------------
>
>                 Key: CASSANDRA-21632
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-21632
>             Project: Apache Cassandra
>          Issue Type: Bug
>          Components: Local/SSTable, Local/Startup and Shutdown
>            Reporter: Alexandre Viau
>            Assignee: Alexandre Viau
>            Priority: Normal
>              Labels: patch-available
>             Fix For: 5.0.x, 6.x, 7.x
>
>         Attachments: ci_summary_apache_5.0_199.html, 
> ci_summary_apache_6.0_139.html, ci_summary_apache_trunk_696.html, 
> results_details_apache_5.0_199.tar.xz, results_details_apache_6.0_139.tar.xz, 
> results_details_apache_trunk_696.tar.xz
>
>          Time Spent: 2.5h
>  Remaining Estimate: 0h
>
> When a table has bloom_filter_fp_chance = 1, PartitionIndex.load warms the 
> entire Partitions.db by seeking to every 4096-byte offset and reading a 
> single byte. The warm is unbounded. Nothing relates the amount read to the 
> amount of page cache the node can actually retain
>  
> On our cluster (5.4 TiB and 32.5B partitions per node, bloom_filter_fp_chance 
> = 1, Partitions.db totalling 309.47 GiB across 798 files, or 81,125,849 pages 
> to touch), roughly 70 GiB of page cache is available to the process. The warm 
> reads 309 GiB to retain at most a fraction of it, and startup takes roughly 
> 90 minutes, essentially all of it in SSTableReader.openAll.



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