Doubt regarding mem cache.

[Rakhi Khatwani <rk...@gmail.com>]

Hi,
I am not very clear as to how does the mem cache thing works.

1. When you set memcache to say 1MB, does hbase write all the table
information into some cache memory and when the size reaches IMB, it writes
into hadoop and after that the replication takes place???

2. Is there any minimum limit on the mem cache property in hbase site??

Regards,
Raakhi

Re: Doubt regarding mem cache.

[Erik Holstad <er...@gmail.com>]

Hi Rakhi!

On Wed, Aug 12, 2009 at 11:49 AM, Rakhi Khatwani <rk...@gmail.com>wrote:

> Hi,
> I am not very clear as to how does the mem cache thing works.


MemCache was a name that was used and caused some confusion of what the
purpose of it is.
It has now been renamed to MemStore and is basically a write buffer that
gets flushed to disk/HDFS
when it is too big.

>
> 1. When you set memcache to say 1MB, does hbase write all the table
> information into some cache memory and when the size reaches IMB, it writes
> into hadoop and after that the replication takes place???
>
So yeah, kinda

>
> 2. Is there any minimum limit on the mem cache property in hbase site??
>
Not sure if there is a minimum limit but have a look at hbase-default .xml
and
you will see a bunch of settings for memStore

>
> Regards,
> Raakhi


Regards Erik