LSM-Trees

[karthik tunga <ka...@gmail.com>]

Hi,

I am reading about LSM trees (in HBase : The Definitive guide) and
wondering if the log file mention is nothing but the write-ahead log
(WAL) in HBase?
If it is , how are sequential writes guaranteed when write to WAL is
set to false ?

Sorry if I am missing or have misunderstood something here.

Cheers,
Karthik

Re: LSM-Trees

[karthik tunga <ka...@gmail.com>]

Thanks George.

Cheers,
Karthik

On 5 July 2011 12:13, Lars George <la...@gmail.com> wrote:
> Hi Karthik,
>
> Yes, that is correct. If you disable the WAL on puts (and deletes) then you
> are on your own. In other words, using the WAL is what you want pretty much
> all the time. But there are rare cases where it makes sense to bypass it.
>
> Lars
>
> On Mon, Jul 4, 2011 at 10:42 AM, karthik tunga <ka...@gmail.com>wrote:
>
>> Hi,
>>
>> I am reading about LSM trees (in HBase : The Definitive guide) and
>> wondering if the log file mention is nothing but the write-ahead log
>> (WAL) in HBase?
>> If it is , how are sequential writes guaranteed when write to WAL is
>> set to false ?
>>
>> Sorry if I am missing or have misunderstood something here.
>>
>> Cheers,
>> Karthik
>>
>

Re: LSM-Trees

[Lars George <la...@gmail.com>]

Hi Karthik,

Yes, that is correct. If you disable the WAL on puts (and deletes) then you
are on your own. In other words, using the WAL is what you want pretty much
all the time. But there are rare cases where it makes sense to bypass it.

Lars

On Mon, Jul 4, 2011 at 10:42 AM, karthik tunga <ka...@gmail.com>wrote:

> Hi,
>
> I am reading about LSM trees (in HBase : The Definitive guide) and
> wondering if the log file mention is nothing but the write-ahead log
> (WAL) in HBase?
> If it is , how are sequential writes guaranteed when write to WAL is
> set to false ?
>
> Sorry if I am missing or have misunderstood something here.
>
> Cheers,
> Karthik
>