[jira] [Commented] (CASSANDRA-5657) remove deprecated metrics
[ https://issues.apache.org/jira/browse/CASSANDRA-5657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14288523#comment-14288523 ] Aleksey Yeschenko commented on CASSANDRA-5657: -- Attached nits.txt with some nits and issues fixed: - fixed the mixup in SEP#newExecutor() argument order - StageManager#multiThreadedLowSignalStage() was calling them in the wrong order otherwise - removed unused fields in LatencyMetrics - replaced silly looking Stage#isJmxHidden() Otherwise the branch mostly LGTM, +1. P.S. There are many imports in wrong order, redundant @Override-s when implementing interface/abstract methods (I assume automatically generated), and else/catch on the same line as the closing bracket. Ideally those should be fixed on commit. > remove deprecated metrics > - > > Key: CASSANDRA-5657 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5657 > Project: Cassandra > Issue Type: Task > Components: Tools >Reporter: Jonathan Ellis >Assignee: T Jake Luciani > Labels: technical_debt > Fix For: 3.0 > > Attachments: 5657.txt, 5657v2.txt, nits.txt > > -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-5657) remove deprecated metrics
[ https://issues.apache.org/jira/browse/CASSANDRA-5657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14149588#comment-14149588 ] Nick Bailey commented on CASSANDRA-5657: Yeah if the metric is just a simple counter then a recent* method exposing it isn't really necessary. You can just track the difference between calls. The more complicated metrics like latency (total recent latency / total recent requests) are better exposed by the 1/5/15 minute rate metrics you mentioned. That said, last I checked there were a few recent* metrics that didn't have a 1/5/15 minute rate equivalent. For example Key/RowCacheRecentHitRate. > remove deprecated metrics > - > > Key: CASSANDRA-5657 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5657 > Project: Cassandra > Issue Type: Task > Components: Tools >Reporter: Jonathan Ellis >Assignee: T Jake Luciani > Labels: technical_debt > Fix For: 3.0 > > Attachments: 5657.txt > > -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-5657) remove deprecated metrics
[ https://issues.apache.org/jira/browse/CASSANDRA-5657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14136814#comment-14136814 ] Benedict commented on CASSANDRA-5657: - It looks like we could still plugin to reporting frameworks by implementing Histogram or Timer, ignoring the internal state we won't be using and simply overriding all of the relevant methods. It would waste a small amount of main memory, but would be otherwise fine. > remove deprecated metrics > - > > Key: CASSANDRA-5657 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5657 > Project: Cassandra > Issue Type: Task > Components: Tools >Reporter: Jonathan Ellis >Assignee: T Jake Luciani > Labels: technical_debt > Fix For: 3.0 > > -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-5657) remove deprecated metrics
[ https://issues.apache.org/jira/browse/CASSANDRA-5657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14136810#comment-14136810 ] Benedict commented on CASSANDRA-5657: - There is some brief discussion of this in CASSANDRA-6486, although it hasn't been updated in a while. The main functional problems with yammer are: * *Lack of accuracy for latency numbers, especially at the tail end (which is generally the only number users are really interested in. This is the most important issue)* * Lack of accuracy over time horizons (i.e. 5m numbers are not really 5m numbers, they're just weighted more towards that window) * No attempt to deal with coordinated omission Also, there are issues with performance. Although these are mild, they are mounting as we introduce more and more metrics, and reduce other costs * These are the only likely-to-block calls on the typical read/write path now * They pollute the CPU cache through the use of LongAdder - we have hundreds of LongAdders we touch across a node, which is wasteful given competition to updates is not very high; each Timer has three long adders it updates. * The exponentially decaying sample is performed with a heavy-weight data structure with complex objects, where a simple primitive array would suffice. This compounds the accuracy problem, as each sample occupies a LOT of space (probably ~100 bytes), so our sample is at least 10 times smaller than it could be. It also requires several CAS operations to maintain. In general I favour the maintenance of one shared latency structure per thread for all latency measurements, which is aggregated periodically to maintain cross server statistics. This bounds the wasted memory much lower, ensures no competition for updates, no cache coherency traffic, and no unnecessary cache pollution. > remove deprecated metrics > - > > Key: CASSANDRA-5657 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5657 > Project: Cassandra > Issue Type: Task > Components: Tools >Reporter: Jonathan Ellis >Assignee: T Jake Luciani > Labels: technical_debt > Fix For: 3.0 > > -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-5657) remove deprecated metrics
[ https://issues.apache.org/jira/browse/CASSANDRA-5657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14136610#comment-14136610 ] T Jake Luciani commented on CASSANDRA-5657: --- I'm not sure what about yammer metrics is lacking, I find them to be very simple and easy to integrate. If the histogram is lacking detail I'm happy to keep the old ones around. But you seem to mean they are not accurate? > remove deprecated metrics > - > > Key: CASSANDRA-5657 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5657 > Project: Cassandra > Issue Type: Task > Components: Tools >Reporter: Jonathan Ellis >Assignee: T Jake Luciani > Labels: technical_debt > Fix For: 3.0 > > -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-5657) remove deprecated metrics
[ https://issues.apache.org/jira/browse/CASSANDRA-5657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14135464#comment-14135464 ] Benedict commented on CASSANDRA-5657: - This does _not_ appear to be the same as the just closed CASSANDRA-7943, which suggests dropping 'legacy metrics' - which seems to refer to the custom histogram. This ticket refers to removing deprecated mbeans and object wrappers only. I am -1 dropping the legacy histograms, since they are considerably more accurate than the yammer histograms. Before we consider dropping them we need to consider holistically our approach to metrics, which really need overhauling, since yammer metrics are lacking. > remove deprecated metrics > - > > Key: CASSANDRA-5657 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5657 > Project: Cassandra > Issue Type: Task > Components: Tools >Reporter: Jonathan Ellis >Assignee: T Jake Luciani > Labels: technical_debt > Fix For: 3.0 > > -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (CASSANDRA-5657) remove deprecated metrics
[ https://issues.apache.org/jira/browse/CASSANDRA-5657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13934083#comment-13934083 ] Jonathan Ellis commented on CASSANDRA-5657: --- 3.0 is probably the right place to do this. > remove deprecated metrics > - > > Key: CASSANDRA-5657 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5657 > Project: Cassandra > Issue Type: Task > Components: Tools >Reporter: Jonathan Ellis >Assignee: Yuki Morishita > Fix For: 3.0 > > -- This message was sent by Atlassian JIRA (v6.2#6252)
