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From Bill Havanki <bhava...@clouderagovt.com>
Subject Re: Supporting large values
Date Tue, 27 May 2014 21:09:52 GMT
I left the default key size constraint in place. I had set the tserver
mesage size up from 1 GB to 1.5 GB, but it didn't help. (I forgot that
config item.)

Stack trace(s) coming up! I got tired of failures all day so I'm running a
different test that will hopefully work. I'll re-break it shortly :D


On Tue, May 27, 2014 at 5:04 PM, Josh Elser <josh.elser@gmail.com> wrote:

> Stack traces would definitely be helpful, IMO.
>
> (or interesting if nothing else :D)
>
>
> On 5/27/14, 4:55 PM, Bill Havanki wrote:
>
>> No sir. I am seeing general out of heap space messages, nothing about
>> direct buffers. One specific example would be while Thrift is writing to a
>> ByteArrayOutputStream to send off scan results. (I can get an exact stack
>> trace - easily :} - if it would be helpful.) It seems as if there just
>> isn't enough heap left, after controlling for what I have so far.
>>
>> As a clarification of my original email: each row has 100 cells, and each
>> cell has a 100 MB value. So, one row would occupy just over 10 GB.
>>
>>
>> On Tue, May 27, 2014 at 4:49 PM, <dlmarion@comcast.net> wrote:
>>
>>  Are you seeing something similar to the error in
>>> https://issues.apache.org/jira/browse/ACCUMULO-2495?
>>>
>>> ----- Original Message -----
>>>
>>> From: "Bill Havanki" <bhavanki@clouderagovt.com>
>>> To: "Accumulo Dev List" <dev@accumulo.apache.org>
>>> Sent: Tuesday, May 27, 2014 4:30:59 PM
>>> Subject: Supporting large values
>>>
>>> I'm trying to run a stress test where each row in a table has 100 cells,
>>> each with a value of 100 MB of random data. (This is using Bill Slacum's
>>> memory stress test tool). Despite fiddling with the cluster
>>> configuration,
>>> I always run out of tablet server heap space before too long.
>>>
>>> Here are the configurations I've tried so far, with valuable guidance
>>> from
>>> Busbey and madrob:
>>>
>>> - native maps are enabled, tserver.memory.maps.max = 8G
>>> - table.compaction.minor.logs.threshold = 8
>>> - tserver.walog.max.size = 1G
>>> - Tablet server has 4G heap (-Xmx4g)
>>> - table is pre-split into 8 tablets (split points 0x20, 0x40, 0x60,
>>> ...), 5
>>> tablet servers are available
>>> - tserver.cache.data.size = 256M
>>> - tserver.cache.index.size = 40M (keys are small - 4 bytes - in this
>>> test)
>>> - table.scan.max.memory = 256M
>>> - tserver.readahead.concurrent.max = 4 (default is 16)
>>>
>>> It's often hard to tell where the OOM error comes from, but I have seen
>>> it
>>> frequently coming from Thrift as it is writing out scan results.
>>>
>>> Does anyone have any good conventions for supporting large values?
>>> (Warning: I'll want to work on large keys (and tiny values) next! :) )
>>>
>>> Thanks very much
>>> Bill
>>>
>>> --
>>> // Bill Havanki
>>> // Solutions Architect, Cloudera Govt Solutions
>>> // 443.686.9283
>>>
>>>
>>>
>>
>>


-- 
// Bill Havanki
// Solutions Architect, Cloudera Govt Solutions
// 443.686.9283

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