in_memory column family records should be available in memory past memstore
flush if total memory to habse > memory to memstore
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Key: HBASE-3067
URL: https://issues.apache.org/jira/browse/HBASE-3067
Project: HBase
Issue Type: Improvement
Affects Versions: 0.89.20100621
Reporter: Abhijit Pol
On Fri, Oct 1, 2010 at 8:31 AM, Stack <[email protected]> wrote:
Blockcache is made of blocks pulled from HDFS. It'd be a little awkward
inserting hot records into the block cache w/o going via HDFS.
But, yes, you have a good point that flush is disruptive of hot records.
In the past we talked of a keyvalue cache on top of the block cache but it fell
out of favor because block cache seemed to be good enough but sounds like we
need to revive it or do some fancy dancing if column family is marked
in-memory, we keep around the snapshot of memstore until we know the block
cache has been populated?
Any other suggestions?
On Fri, Oct 1, 2010 at 1:26 AM, Abhijit Pol <[email protected]> wrote:
> we are trying to read efficiently a hot column family (in_memory=true,
> blockcaching=true) that get writes at say 500 qps and reads at 10,000 qps.
> - as long as writes are in memstore we get them from memstore and its fast
> - if we have read it once it will be at least in block cache (gets priority
> due to in_memory=true) and subsequent reads are faster
> - however memstore flush puts records on disk which demands for disk IO to
> get them back in block cache
>
> is there a way for memstore flush to go to blockcache?
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