Enis Soztutar created HBASE-15376:
-------------------------------------
Summary: ScanNext metric is size-based while every other
per-operation metric is time based
Key: HBASE-15376
URL: https://issues.apache.org/jira/browse/HBASE-15376
Project: HBase
Issue Type: Sub-task
Reporter: Enis Soztutar
We have per-operation metrics for {{Get}}, {{Mutate}}, {{Delete}},
{{Increment}}, and {{ScanNext}}.
The metrics are emitted like:
{code}
"Get_num_ops" : 4837505,
"Get_min" : 0,
"Get_max" : 296,
"Get_mean" : 0.2934618155433431,
"Get_median" : 0.0,
"Get_75th_percentile" : 0.0,
"Get_95th_percentile" : 1.0,
"Get_99th_percentile" : 1.0,
...
"ScanNext_num_ops" : 194705,
"ScanNext_min" : 0,
"ScanNext_max" : 18441,
"ScanNext_mean" : 7468.274651395701,
"ScanNext_median" : 583.0,
"ScanNext_75th_percentile" : 583.0,
"ScanNext_95th_percentile" : 13481.0,
"ScanNext_99th_percentile" : 13481.0,
{code}
The problem is that all of Get,Mutate,Delete,Increment,Append,Replay are time
based tracking how long the operation ran, while ScanNext is tracking returned
response sizes (returned cell-sizes to be exact). Obviously, this is very
confusing and you would only know this subtlety if you read the metrics
collection code.
Not sure how useful is the ScanNext metric as it is today. We can deprecate it,
and introduce a time based one to keep track of scan request latencies.
ps. Shamelessly using the parent jira (since these seem relavant).
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
