On Mon, Mar 31, 2014 at 10:37 AM, Rendon, Carlos (KBB) <[email protected]>wrote:
> Table does not exist yet. I'm expecting random access across the rowkey > namespace. I also expect bursts of access to a given row, all of which will > change its contents and also read it. > > My question is from reading here: > https://hbase.apache.org/book/regionserver.arch.html#block.cache > that blockcache wastes memory/CPU/GCs if there aren't many hits to it or > if you have random writes that you typically don't read. So I was wondering > if writing on every read had the same effect. > > After reading the recent thread "Cache invalidation in Blockcache" I can > see that during bursts the reads would be coming from the memstore and also > that reads still need to be made to the underlying HFiles because data from > both sources are merged together to produce a result. > > In the scenario I have, it sounds like it is useful to have the HFile > blocks cached in the blockcache, even if the data ultimately is returned > from the memstore due to a recent write. > And enable cache on write if you are frequently going to be just reading back what you wrote? St.Ack
