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From Sam Seigal <selek...@yahoo.com>
Subject Re: Row get very slow
Date Mon, 14 Nov 2011 19:37:47 GMT
If you are not too concerned with random access time, but want more
efficient scans, is increasing the block size then a good idea ?

On Mon, Nov 14, 2011 at 11:24 AM, lars hofhansl <lhofhansl@yahoo.com> wrote:
> Did it speed up your queries? As you can see from the followup discussions here, there
is some general confusion around this.
>
> Generally there are 2 sizes involved:
> 1. HBase Filesize
> 2. HBase Blocksize
>
> #1 sets the maximum size of a region before it is split. Default used to be 512mb, it's
now 1g (but usually it should be even larger)
>
> #2 is the size of the blocks inside the HFiles. Smaller blocks mean better random access,
but larger block indexes. I would only increase that if you have large cells.
>
> -- Lars
> ________________________________
>
> From: Damien Hardy <dhardy@figarocms.fr>
> To: user@hbase.apache.org
> Sent: Monday, November 14, 2011 12:51 AM
> Subject: Re: Row get very slow
>
> Le 13/11/2011 16:13, Arvind Jayaprakash a écrit :
>> A common confusion is b/w MAX_FILESIZE and BLOCKSIZE. Given that
>> MAX_FILESIZE is not listed on :60010/master.jsp, one tends to assume
>> BLOCKSIZE represents that value.
>>
>> On Nov 10, lars hofhansl wrote:
>>> "BLOCKSIZE =>  '536870912'"
>>>
>>>
>>> You set your blocksize to 512mb? The default is 64k (65536), try to set it to
something lower.
>
>
> Hello,
>
> Thank you for answer I have just altered my table and launched a major_compact to get
it effective.
>
> I thought that increasing FILSIZE of HBases implies somehow changes on the BLOSKSIZE
of my tables and to prevent unbalanced paramaters increased it too ... #FAIL.
>
> The question is : in what application BLOCKSIZE should be changed (increased or decreased)
?
>
> Thank you.
>
> -- Damien
>

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