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https://issues.apache.org/jira/browse/HBASE-5162?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Lars Hofhansl updated HBASE-5162:
---------------------------------

    Fix Version/s:     (was: 0.94.0)
                   0.94.1

Let's aim for 0.94.1 with this.
                
> Basic client pushback mechanism
> -------------------------------
>
>                 Key: HBASE-5162
>                 URL: https://issues.apache.org/jira/browse/HBASE-5162
>             Project: HBase
>          Issue Type: New Feature
>    Affects Versions: 0.92.0
>            Reporter: Jean-Daniel Cryans
>             Fix For: 0.94.1
>
>         Attachments: java_HBASE-5162.patch
>
>
> The current blocking we do when we are close to some limits (memstores over 
> the multiplier factor, too many store files, global memstore memory) is bad, 
> too coarse and confusing. After hitting HBASE-5161, it really becomes obvious 
> that we need something better.
> I did a little brainstorm with Stack, we came up quickly with two solutions:
>  - Send some exception to the client, like OverloadedException, that's thrown 
> when some situation happens like getting past the low memory barrier. It 
> would be thrown when the client gets a handler and does some check while 
> putting or deleting. The client would treat this a retryable exception but 
> ideally wouldn't check .META. for a new location. It could be fancy and have 
> multiple levels of pushback, like send the exception to 25% of the clients, 
> and then go up if the situation persists. Should be "easy" to implement but 
> we'll be using a lot more IO to send the payload over and over again (but at 
> least it wouldn't sit in the RS's memory).
>  - Send a message alongside a successful put or delete to tell the client to 
> slow down a little, this way we don't have to do back and forth with the 
> payload between the client and the server. It's a cleaner (I think) but more 
> involved solution.
> In every case the RS should do very obvious things to notify the operators of 
> this situation, through logs, web UI, metrics, etc.
> Other ideas?

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