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Posted to commits@cassandra.apache.org by "Dmitry Konstantinov (Jira)" <ji...@apache.org> on 2026/05/28 16:53:00 UTC
[jira] [Comment Edited] (CASSANDRA-21399) Megamorphic call overhead at org.apache.cassandra.io.util.RandomAccessReader#current
[ https://issues.apache.org/jira/browse/CASSANDRA-21399?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18084152#comment-18084152 ]
Dmitry Konstantinov edited comment on CASSANDRA-21399 at 5/28/26 4:52 PM:
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same story is about fileLength, in total 1.4% of CPU
!isEOF_cpu.png|width=600!
was (Author: dnk):
same story is about fileLength, in total 1.4% of CPU
!isEOF_cpu.png!
> Megamorphic call overhead at org.apache.cassandra.io.util.RandomAccessReader#current
> ------------------------------------------------------------------------------------
>
> Key: CASSANDRA-21399
> URL: https://issues.apache.org/jira/browse/CASSANDRA-21399
> Project: Apache Cassandra
> Issue Type: Improvement
> Components: Local/SSTable
> Reporter: Dmitry Konstantinov
> Assignee: Dmitry Konstantinov
> Priority: Normal
> Fix For: 6.x, 7.x
>
> Attachments: image-2026-05-23-16-17-07-684.png, isEOF_cpu.png
>
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> 0.9% of overall CPU in profile is spent in org.apache.cassandra.io.util.RandomAccessReader#current
> when we do a polymorphic call of org.apache.cassandra.io.util.Rebufferer.BufferHolder#offset
> we can avoid it by caching the offset value for the current block on RandomAccessReader level.
> !image-2026-05-23-16-17-07-684.png|width=600!
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