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From sulong <sulong1...@gmail.com>
Subject Re: CompactionExecutor holds 8000+ SSTableReader 6G+ memory
Date Fri, 28 Jun 2013 06:14:25 GMT
aaron, thanks for your reply. Yes, I do use the Leveled compactions
strategy, and the SSTable size is 10M. If it happens again, I will try to
enlarge the sstable size.

I just wonder why cassandra doesn't limit the SSTableReader's total memory
usage when compacting. Lots of memory are consumed by the SSTableReader's
cache. Why not clear these cache first at the beginning of compaction?


On Fri, Jun 28, 2013 at 1:14 PM, aaron morton <aaron@thelastpickle.com>wrote:

> Are you running the Levelled compactions strategy ?
> If so what is the max SSTable size and what is the total data per node?
>
>  If you are running it try using a larger SSTable size like 32MB
>
> Cheers
>
>    -----------------
> Aaron Morton
> Freelance Cassandra Consultant
> New Zealand
>
> @aaronmorton
> http://www.thelastpickle.com
>
> On 27/06/2013, at 2:02 PM, sulong <sulong1984@gmail.com> wrote:
>
> According to  the OpsCenter records, yes,  the compaction was running
> then, 8.5mb /s
>
>
> On Thu, Jun 27, 2013 at 9:54 AM, sulong <sulong1984@gmail.com> wrote:
>
>> version: 1.2.2
>> cluster read requests 800/s, write request 22/s
>> Sorrry, I don't know whether  the compaction was running then.
>>
>>
>> On Thu, Jun 27, 2013 at 1:02 AM, Robert Coli <rcoli@eventbrite.com>wrote:
>>
>>> On Tue, Jun 25, 2013 at 10:13 PM, sulong <sulong1984@gmail.com> wrote:
>>> > I have 4 nodes cassandra cluster. Every node has 32G memory, and the
>>> > cassandra jvm uses 8G. The cluster is suffering from gc. Looks like
>>> > CompactionExecutor thread holds too many SSTableReader. See the
>>> attachement.
>>>
>>> What version of Cassandra?
>>> What workload?
>>> Is compaction actually running?
>>>
>>> =Rob
>>>
>>
>>
>
>

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