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From Josh Elser <josh.el...@gmail.com>
Subject Re: tserver.mutation.queue.max default in 1.5
Date Wed, 23 Jul 2014 22:20:18 GMT
Each write thread to a server will consume up to 4x the memory (256K->1M).

For example, 8 write threads to a tserver would take 8M of heap instead 
of 2M (at most).

On 7/23/14, 6:12 PM, David Medinets wrote:
> How does that impact memory usage? Is there some other setting that
> needs to be adjusted at the same time?
>
> On Wed, Jul 23, 2014 at 4:36 PM, Josh Elser <josh.elser@gmail.com> wrote:
>> I started running some tests against 1.5.2 today and was baffled for a few
>> hours with horrid ingest performance (~30% of what I expected).
>>
>> After staring at configs for a while, I finally realized it was because I
>> didn't increase tserver.mutation.queue.max from the default of 256k. Sure
>> enough, this resulted in speeds that I expected.
>>
>> I see that in 1.6.0, the default value for this was increase from 256K to 1M
>> (in ACCUMULO-1905). I know we have it written down in the release notes, but
>> I think the likelihood of causing terrible performance for users is much
>> greater than causing OOMEs (or similar increased memory footprint) problems
>> for users. I would like to change the default for 1.5.2 to 1M to match
>> 1.6.0.
>>
>> Thoughts/worries/complaints?

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