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From Anoop Sam John <anoo...@huawei.com>
Subject RE: Regarding memstoreTS in bulkloaded HFiles
Date Thu, 31 May 2012 03:52:52 GMT
@Stack
> As of now we are not able to set any Block encoder algo as part of bulk loading.
HBASE-6040 will address this issue  :)

>How would we Anoop?  If we create KVs during an upload, the KV
>instance will have a memstorets data member?
 Yes Stack. KV instances will have a long member memstoreTS in it defaults to 0L.  In case
of bulk load this value will remain as it is.
When we use HFile V2, the writer will include the memstoreTS into bytes written as part of
KSs.
As I said in my last mail, this wont use 8 bytes per KV, but 1 byte per KV when the value
is 0. We write it as Vlong type.
(Initially I thought it will be 8 bytes which will be like a huge wastage of space). One byte
also we need to be considered? When the number of records and KVs per records are highs may
be this will take up space...

-Anoop-
________________________________________
From: saint.ack@gmail.com [saint.ack@gmail.com] on behalf of Stack [stack@duboce.net]
Sent: Thursday, May 31, 2012 12:26 AM
To: dev@hbase.apache.org
Subject: Re: Regarding memstoreTS in bulkloaded HFiles

On Tue, May 29, 2012 at 5:55 AM, Anoop Sam John <anoopsj@huawei.com> wrote:
>            In HFile V2 we have introduced the memstore TS to be getting written to the
HFiles. In case of bulk load also, now we are writing a long value as part of every KV. I
think in case of the bulk loading there is no meaning for the memstore TS. Can we avoid this?
>

How would we Anoop?  If we create KVs during an upload, the KV
instance will have a memstorets data member?

> As of now we are not able to set any Block encoder algo as part of bulk loading.

This would be a nice feature.  Some of the encodings are intensive so
doing it offline would be sweet for read-heavy deploys.

> Do we need to think making the memstoreTS write into the HFile (in version 2) as some
way configurable? In case of bulk loading we can turn it OFF. Pls correct me if my understanding
is wrong
>

What you thinking?  This could be a nice addtiion.
St.Ack

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