hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Heng Chen (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-15376) ScanNext metric is size-based while every other per-operation metric is time based
Date Thu, 03 Mar 2016 02:43:18 GMT

    [ https://issues.apache.org/jira/browse/HBASE-15376?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15177041#comment-15177041
] 

Heng Chen commented on HBASE-15376:
-----------------------------------

{code}
The https://hbase.apache.org/book.html#hbase.versioning page says that there is no operational
compatibility between minor versions, so according to the previously agreed on guidelines,
we can (but do not need to) in fact change the name of the metrics in 1.3+.
{code}

You are right.  So we have no plan to backport it to branch-1.0+ (just add metrics for scan
time) ?

> 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
>         Attachments: HBASE-15376.patch
>
>
> 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)

Mime
View raw message