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From Stack <st...@duboce.net>
Subject Re: HBase row level cache for random read
Date Sat, 18 Aug 2012 19:33:52 GMT
On Fri, Aug 17, 2012 at 4:42 PM, Gen Liu <geliu@zynga.com> wrote:
> I assume block cache store compressed data,

Generally its not, not unless you use block encoding.

> one block can hold 6 rows, but in random read, maybe 1 row is ever accessed, 5/6 of the
cache space is wasted.
> Is there a better way of caching for random read. Lower the block size to 32k or even
16k might be a choice.

We don't seem to list this as an option in this section,
http://hbase.apache.org/book.html#perf.reading, but yes, if lots of
random reads, smaller block cache could make a difference.


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