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From Віталій Тимчишин <tiv...@gmail.com>
Subject Re: Cassandra dying when gets many deletes
Date Sun, 06 May 2012 18:51:48 GMT
Thanks a lot. It seems that a fix is commited now and fix will appear in
the next release, so I won't need my own patched cassandra :)

Best regards, Vitalii Tymchyshyn.

2012/5/3 Andrey Kolyadenko <akolyadenko@gmail.com>

> Hi Vitalii,
>
> I sent patch.
>
>
> 2012/4/24 Віталій Тимчишин <tivv00@gmail.com>
>
>> Glad you've got it working properly. I've tried to make as "local"
>> changes as possible, so changed only single value calculation. But it's
>> possible your way is better and will be accepted by cassandra maintainer.
>> Could you attach your patch to the ticket. I'd like for any fix to be
>> applied to the trunk since currently I have to make my own patched build
>> each time I upgrade because of the bug.
>>
>> Best regards, Vitalii Tymchyshyn
>>
>> 25 квітня 2012 р. 09:08 crypto five <cryptofive@gmail.com> написав:
>>
>> I agree with your observations.
>>> From another hand I found that ColumnFamily.size() doesn't calculate
>>> object size correctly. It doesn't count two fields Objects sizes and
>>> returns 0 if there is no object in columns container.
>>> I increased initial size variable value to 24 which is size of two
>>> objects(I didn't now what's correct value), and cassandra started
>>> calculating live ratio correctly, increasing trhouhput value and flushing
>>> memtables.
>>>
>>> On Tue, Apr 24, 2012 at 2:00 AM, Vitalii Tymchyshyn <tivv00@gmail.com>wrote:
>>>
>>>> **
>>>> Hello.
>>>>
>>>> For me " there are no dirty column families" in your message tells it's
>>>> possibly the same problem.
>>>> The issue is that column families that gets full row deletes only do
>>>> not get ANY SINGLE dirty byte accounted and so can't be picked by flusher.
>>>> Any ratio can't help simply because it is multiplied by 0. Check your
>>>> cfstats.
>>>>
>>>> 24.04.12 09:54, crypto five написав(ла):
>>>>
>>>> Thank you Vitalii.
>>>>
>>>>  Looking at the Jonathan's answer to your patch I think it's probably
>>>> not my case. I see that LiveRatio is calculated in my case, but
>>>> calculations look strange:
>>>>
>>>>  WARN [MemoryMeter:1] 2012-04-23 23:29:48,430 Memtable.java (line 181)
>>>> setting live ratio to maximum of 64 instead of Infinity
>>>>  INFO [MemoryMeter:1] 2012-04-23 23:29:48,432 Memtable.java (line 186)
>>>> CFS(Keyspace='lexems', ColumnFamily='countersCF') liveRatio is 64.0
>>>> (just-counted was 64.0).  calculation took 63355ms for 0 columns
>>>>
>>>>  Looking at the comments in the code: "If it gets higher than 64
>>>> something is probably broken.", looks like it's probably the problem.
>>>> Not sure how to investigate it.
>>>>
>>>> 2012/4/23 Віталій Тимчишин <tivv00@gmail.com>
>>>>
>>>>> See https://issues.apache.org/jira/browse/CASSANDRA-3741
>>>>> I did post a fix there that helped me.
>>>>>
>>>>>
>>>>> 2012/4/24 crypto five <cryptofive@gmail.com>
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>>  I have 50 millions of rows in column family on 4G RAM box. I
>>>>>> allocatedf 2GB to cassandra.
>>>>>> I have program which is traversing this CF and cleaning some data
>>>>>> there, it generates about 20k delete statements per second.
>>>>>> After about of 3 millions deletions cassandra stops responding to
>>>>>> queries: it doesn't react to CLI, nodetool etc.
>>>>>> I see in the logs that it tries to free some memory but can't even
if
>>>>>> I wait whole day.
>>>>>> Also I see following in  the logs:
>>>>>>
>>>>>>  INFO [ScheduledTasks:1] 2012-04-23 18:38:13,333 StorageService.java
>>>>>> (line 2647) Unable to reduce heap usage since there are no dirty
column
>>>>>> families
>>>>>>
>>>>>>  When I am looking at memory dump I see that memory goes to
>>>>>> ConcurrentSkipListMap(10%), HeapByteBuffer(13%), DecoratedKey(6%),
>>>>>> int[](6%), BigInteger(8.2%), ConcurrentSkipListMap$HeadIndex(7.2%),
>>>>>> ColumnFamily(6.5%), ThreadSafeSortedColumns(13.7%), long[](5.9%).
>>>>>>
>>>>>>  What can I do to make cassandra stop dying?
>>>>>> Why it can't free the memory?
>>>>>> Any ideas?
>>>>>>
>>>>>>  Thank you.
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>>   --
>>>>> Best regards,
>>>>>  Vitalii Tymchyshyn
>>>>>
>>>>
>>>>
>>>>
>>>
>>
>>
>> --
>> Best regards,
>>  Vitalii Tymchyshyn
>>
>
>


-- 
Best regards,
 Vitalii Tymchyshyn

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