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 <[email protected]> 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 <[email protected]> > To: [email protected] > 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 >
