[jira] [Updated] (CASSANDRA-8417) Default base_time_seconds in DTCS is almost always too large

["Björn Hegerfors (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CASSANDRA-8417?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Björn Hegerfors updated CASSANDRA-8417:
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    Attachment: cassandra-trunk-CASSANDRA-8417-basetime60.txt

Sorry about the delayed response. I went with 1 minute. Indeed there's not much of a downside with a too small baseTime. A too big baseTime is much more damaging for performance. It's very much analogous to min_sstable_size in STCS, which would also be bad to set too high, while a very low value ought to not hurt performance much, compared to the ideal value (whatever that is). It will leave very small SSTable scattered for a while longer, which means that there might be more SSTables on disk. But these new SSTables are likely to be in disk cache anyway, right? So I'd go with 60 seconds as a "better safe than sorry"  measure.

> Default base_time_seconds in DTCS is almost always too large
> ------------------------------------------------------------
>
>                 Key: CASSANDRA-8417
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-8417
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Jonathan Ellis
>            Assignee: Björn Hegerfors
>             Fix For: 2.0.12, 2.1.3
>
>         Attachments: cassandra-trunk-CASSANDRA-8417-basetime60.txt
>
>
> One hour is a very long time to compact all new inserts together with any reasonable volume at all.



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