[ https://issues.apache.org/jira/browse/CASSANDRA-16760?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Caleb Rackliffe updated CASSANDRA-16760: ---------------------------------------- Status: Review In Progress (was: Patch Available) > JMXTimer exposes attributes in inconsistent time units > ------------------------------------------------------ > > Key: CASSANDRA-16760 > URL: https://issues.apache.org/jira/browse/CASSANDRA-16760 > Project: Cassandra > Issue Type: Improvement > Components: Legacy/Observability > Reporter: Yifan Cai > Assignee: Yifan Cai > Priority: Normal > Fix For: 4.x > > Time Spent: 10m > Remaining Estimate: 0h > > JMXTimer objects are constructed with a duration time unit, which is fixed to > MICROSECONDS in the codebase. According to that, we should expect the time > values returned from the JXMTimer are in micros. > However, the time unit is inconsistent among the JMXTimer attributes. > Most of the attributes such as percentiles and mean values returned are in > micros, except Values and RecentValues. > Those 2 attributes expose the raw histogram values of the underlying Timer > (CodaHale) and the values are fixed to be based on nanos. > The inconsistency leads to confusion and mis-interpretation of the values, if > the end user is not familiar with the implementation details. One may > consider the Values and RecentValues are also in micros. > Besides the confusion, given the intention is to record the time values in > the micros resolution, we do not need to allocate 165 buckets in the > DecayingEstimatedHistogramReservoir. 165 buckets is necessary for nanos, but > not for micros. We can only allocate 90 buckets and it should reduce ~50% > memory footprint used by the Timers. > I'd like to propose an approach to scale the values being recorded in the > reservoirs used by Timers and reduce the allocation. -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org