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From Anoop John <anoop.hb...@gmail.com>
Subject Re: How does BlockCache find relevant Blocks?
Date Wed, 29 May 2013 11:45:12 GMT
There is an index for the blocks in a HFile. This index contains details
like start row in the block, its offset and length in the HFile...   So as
a 1st setp to get a rowkey, we will find this rk can be present in which
HFile block.. (I am assuming only one HFile as of now)..   Now we will see
whether this block is already present in the block cache or not. If so try
finding the row within that block..   If this HFile block is not present in
the cache, we will load it from HDFS..

Hope this helps u..


On Wed, May 29, 2013 at 4:40 PM, yun peng <pengyunmomo@gmail.com> wrote:

> Hi, All,
> Given a large-sized BlockCache, I am wondering how HBase performs to search
> a block of a requested rowkey. Is there any index structure (in-memory)
> inside BlockCache? or it search in a brute force way, (which seems unlikely
> though :-...)
> I am aware of reference guide online, but have not yet find the answer...
> http://hbase.apache.org/book.html#block.cache
> Thx,
> Yun

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