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From aaron morton <aa...@thelastpickle.com>
Subject Re: Memtables stored in which location
Date Thu, 21 Jul 2011 10:45:29 GMT
Try the project wiki here http://wiki.apache.org/cassandra/ArchitectureOverview or the my own
blog here
http://thelastpickle.com/2011/04/28/Forces-of-Write-and-Read/

There is also a list of articles on the wiki here http://wiki.apache.org/cassandra/ArticlesAndPresentations

in short, writes got to the commit log first, then the memtable in memory, which is later
flushed to disk. A read is from potentially multiple sstables and memtables. 

Cheers

-----------------
Aaron Morton
Freelance Cassandra Developer
@aaronmorton
http://www.thelastpickle.com

On 21 Jul 2011, at 21:17, CASSANDRA learner wrote:

> Hi,
> 
> You r right but i too have some concerns...
> 
> Any ways , some where memtable has to be stored right, like we say memtable data is flushed
to create sstable on disk.
> Exactly from which location or memory it will be getting from. is it like an objects
streams or like it is storing the values in commitlog.
> my next question is , data is written to commit log. all the data is available here,
and the sstable are getting created on disk, then where and when these memtables are coming
into picture
> 
> On Thu, Jul 21, 2011 at 1:44 PM, samal <samal@wakya.in> wrote:
> SSTable is stored on disk not memtable.
> 
> Memtable is memory representation of data, which is on flush to create SSTable on disk.
> 
> This is the location where SSTable is stored
> https://github.com/apache/cassandra/blob/trunk/conf/cassandra.yaml#L71
> 
> 
> Where as Commitlog which is back up (log) for memtable replaying store in
> https://github.com/apache/cassandra/blob/trunk/conf/cassandra.yaml#L75
> location.
> 
> Once the all memtable is flushed to disk, new commit log segment is created.
> 
> On Thu, Jul 21, 2011 at 1:12 PM, Abdul Haq Shaik <abdulsk.cassandra@gmail.com>
wrote:
> Hi,
> 
> Can you please let me know where exactly the memtables are getting stored. I wanted to
know the physical location
> 
> 


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