Re: Cassandra 4.1 compaction thread no longer low priority (cpu nice)

Thank you for highlighting this, it looks like I need to refresh my knowledge about IO schedulers :-) Cheers, Dmitry On Thu, 22 Feb 2024 at 22:18, Bowen Song via user wrote: > On the IO scheduler point, cfq WAS the only scheduler supporting IO > priorities (such as ionice) shipped by default wi

Re: Cassandra 4.1 compaction thread no longer low priority (cpu nice)

On the IO scheduler point, cfq WAS the only scheduler supporting IO priorities (such as ionice) shipped by default with the Linux kernel, but that has changed since bfq and mq-deadline were added to the Linux kernel. Both bfq and mq-deadline supports IO priority, as documented here: https://doc

Re: Cassandra 4.1 compaction thread no longer low priority (cpu nice)

Hi all, I was not participating in the changes but I analyzed the question some time ago from another side. There were also changes related to -XX:ThreadPriorityPolicy JVM option. When you set a thread priority for a Java thread it does not mean it is always propagated as a native OS thread priori

Re: Cassandra 4.1 compaction thread no longer low priority (cpu nice)

Hi Pierre, Is there anything stopping you from using the compaction_throughput option in the cassandra.yaml file to manage the performance impact of compaction operations? With thread

Cassandra 4.1 compaction thread no longer low priority (cpu nice)

Hello all, I've recently upgraded to Cassandra 4.1 and see a change in compaction behavior that seems unwanted: * With Cassandra 3.11 compaction was run by thread in low priority and thus using CPU nice (visible using top) (I believe Cassandra 4.0 also had this behavior) * With Cassandra 4.1,