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From aaron morton <aa...@thelastpickle.com>
Subject Re: Tombstones and memtable_operations
Date Tue, 19 Apr 2011 21:01:21 GMT
How do you do the deletes ?

Aaron

On 20 Apr 2011, at 08:39, Héctor Izquierdo Seliva wrote:

> El mar, 19-04-2011 a las 23:33 +0300, shimi escribió:
>> You can use memtable_flush_after_mins instead of the cron
>> 
>> 
>> Shimi
>> 
> 
> Good point! I'll try that.
> 
> Wouldn't it be better to count a delete as a one column operation so it
> contributes to flush by operations?
> 
>> 2011/4/19 Héctor Izquierdo Seliva <izquierdo@strands.com>
>> 
>>        El mié, 20-04-2011 a las 08:16 +1200, aaron morton escribió:
>>> I think their may be an issue here, we are counting the
>>        number of columns in the operation. When deleting an entire
>>        row we do not have a column count.
>>> 
>>> Can you let us know what version you are using and how you
>>        are doing the delete ?
>>> 
>>> Thanks
>>> Aaron
>>> 
>> 
>> 
>>        I'm using 0.7.4. I have a file with all the row keys I have to
>>        delete
>>        (around 100 million) and I just go through the file and issue
>>        deletes
>>        through pelops.
>> 
>>        Should I manually issue flushes with a cron every x time?
>> 
>> 
>>> On 20 Apr 2011, at 04:21, Héctor Izquierdo Seliva wrote:
>>> 
>>>> Ok, I've read about gc grace seconds, but i'm not sure I
>>        understand it
>>>> fully. Untill gc grace seconds have passed, and there is a
>>        compaction,
>>>> the tombstones live in memory? I have to delete 100
>>        million rows and my
>>>> insert rate is very low, so I don't have a lot of
>>        compactions. What
>>>> should I do in this case? Lower the major compaction
>>        threshold and
>>>> memtable_operations to some very low number?
>>>> 
>>>> Thanks
>>>> 
>>>> El mar, 19-04-2011 a las 17:36 +0200, Héctor Izquierdo
>>        Seliva escribió:
>>>>> Hi everyone. I've configured in one of my column families
>>>>> memtable_operations = 0.02 and started deleting keys. I
>>        have already
>>>>> deleted 54k, but there hasn't been any flush of the
>>        memtable. Memory
>>>>> keeps pilling up and eventually nodes start to do
>>        stop-the-world GCs. Is
>>>>> this the way this is supposed to work or have I done
>>        something wrong?
>>>>> 
>>>>> Thanks!
>>>>> 
>>>> 
>>>> 
>>> 
>> 
>> 
>> 
>> 
>> 
> 
> 


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