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From jason zhao yang <zhaoyangsingap...@gmail.com>
Subject Re: why dose it still have to seach in SSTable when getting data in memtable in the read flow?
Date Mon, 27 Mar 2017 11:59:56 GMT
Hi,

Cassandra uses last-writetime-win strategy.

In memory data doesn't mean it is the latest data due to custom write time,
if data is also in Sstable, Cassandra has to read it and reconcile.

Jasonstack
On Mon, 27 Mar 2017 at 7:53 PM, 赵豫峰 <zhaoyf@easemob.com> wrote:

> hello, I get the message that "If the memtable has the desired partition
> data, then the data is read and then merged with the data from the
> SSTables. The SSTable data is accessed as shown in the following steps."
> in "how is data read?" chapter  in
> http://docs.datastax.com/en/archived/cassandra/2.2/cassandra/dml/dmlAboutReads.html
> .
>
> I do not understand that why have to read SSTable when it has got target
> data in memtable. If the data is in memtable, it means that data is lastest
> one, is there any other reason that it still has to seach in SSTable?
>
> Thanks!
>
>
> ------------------
> 赵豫峰
>
> 环信即时通讯云/研发
>
>

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