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From "Vijay (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (CASSANDRA-4860) Estimated Row Cache Entry size incorrect (always 24?)
Date Sat, 30 Mar 2013 19:11:16 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-4860?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13617978#comment-13617978
] 

Vijay edited comment on CASSANDRA-4860 at 3/30/13 7:09 PM:
-----------------------------------------------------------

Hi Ryan, can you try this one? 

I am really optimistic that this patch should improve the performance without sacrificing
the accuracy of measurement of the memory footprint.
Attached patch doesn't use any reflection, Micro benchmark shows a better performance than
any other approach.

{code}
Completed warmup!, Number of Iteratoions: 1000000
Using reflection took: 8113
Using 4860-v3 took: 95
Using MemoryMeter meter.measure(key) took: 190
Using MemoryMeter meter.measureDeep(key) took: 982
{code}

Note: We don't have this optimization when we have a range tombstone in KeyCache (coz the
code becomes really complex), and while using RowCache.

Let me know if you want me to publish the accuracy test and perf test code.
                
      was (Author: vijay2win@yahoo.com):
    Hi Ryan, can you try this one? 

I am really optimistic that this patch should improve the performance without sacrificing
the accuracy of measurement of the memory footprint.
Attached patch doesn't use any reflection, Micro benchmark shows a better performance than
any other approach.

{code}
Completed warmup!, Number of Iteratoions: 1000000
Using reflection took: 8113
Using 4860-v3 took: 95
Using MemoryMeter meter.measure(key) took: 190
Using MemoryMeter meter.measureDeep(key) took: 982
{code}

We don't have this optimization when we have a range tombstone in KeyCache (coz the code becomes
really complex), and while using RowCache.

Let me know if you want me to publish the accuracy test and perf test code.
                  
> Estimated Row Cache Entry size incorrect (always 24?)
> -----------------------------------------------------
>
>                 Key: CASSANDRA-4860
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-4860
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 1.1.0, 1.2.3, 2.0
>            Reporter: Chris Burroughs
>            Assignee: Vijay
>             Fix For: 1.2.0 beta 3
>
>         Attachments: 0001-4860-v2.patch, 0001-4860-v3.patch, 0001-CASSANDRA-4860-for-11.patch,
0001-CASSANDRA-4860.patch, trunk-4860-revert.patch
>
>
> After running for several hours the RowCacheSize was suspicious low (ie 70 something
MB)  I used  CASSANDRA-4859 to measure the size and number of entries on a node:
> In [3]: 1560504./65021
> Out[3]: 24.0
> In [4]: 2149464./89561
> Out[4]: 24.0
> In [6]: 7216096./300785
> Out[6]: 23.990877204647838
> That's RowCacheSize/RowCacheNumEntires  .  Just to prove I don't have crazy small rows
the mean size of the row *keys* in the saved cache is 67 and Compacted row mean size: 355.
 No jamm errors in the log
> Config notes:
> row_cache_provider: ConcurrentLinkedHashCacheProvider
> row_cache_size_in_mb: 2048
> Version info:
>  * C*: 1.1.6
>  * centos 2.6.32-220.13.1.el6.x86_64
>  * java 6u31 Java HotSpot(TM) 64-Bit Server VM (build 20.6-b01, mixed mode)

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