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https://issues.apache.org/jira/browse/HBASE-10305?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13867592#comment-13867592
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Lars Hofhansl commented on HBASE-10305:
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If you have more regions for the *same* number of a writes this is expected.

Which version of 0.94 are you using? In 0.94.7 or later you have the option to 
defer the log flush (see HBASE-7801,  Mutation.setDurability(...)). Would that 
work for you?


> Batch update performance drops as the number of regions grows
> -------------------------------------------------------------
>
>                 Key: HBASE-10305
>                 URL: https://issues.apache.org/jira/browse/HBASE-10305
>             Project: HBase
>          Issue Type: Bug
>          Components: Performance
>            Reporter: Chao Shi
>
> In our use case, we use a small number (~5) of proxy programs that read from 
> a queue and batch update to HBase. Our program is multi-threaded and HBase 
> client will batch mutations to each RS.
> We found we're getting lower TPS when there are more regions. I think the 
> reason is RS syncs HLog for each region. Suppose there is a single region, 
> the batch update will only touch one region and therefore syncs HLog once. 
> And suppose there are 10 regions per server, in RS#multi() it have to process 
> update for each individual region and sync HLog 10 times.
> Please note that in our scenario, batched mutations usually are independent 
> with each other and need to touch a various number of regions.
> We are using the 0.94 series, but I think the trunk should have the same 
> problem after a quick look into the code.



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