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https://issues.apache.org/jira/browse/HBASE-5162?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14249462#comment-14249462
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stack commented on HBASE-5162:
------------------------------

The test this patch adds has been failing.  You lot on it (i'm sure you are!)

> 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
>            Assignee: Jesse Yates
>             Fix For: 1.0.0, 2.0.0
>
>         Attachments: hbase-5162-branch-1-v0.patch, 
> hbase-5162-trunk-addendum.patch, hbase-5162-trunk-v0.patch, 
> hbase-5162-trunk-v1.patch, hbase-5162-trunk-v10.patch, 
> hbase-5162-trunk-v11.patch, hbase-5162-trunk-v12-committed.patch, 
> hbase-5162-trunk-v2.patch, hbase-5162-trunk-v3.patch, 
> hbase-5162-trunk-v4.patch, hbase-5162-trunk-v5.patch, 
> hbase-5162-trunk-v6.patch, hbase-5162-trunk-v7.patch, 
> hbase-5162-trunk-v8.patch, 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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