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From Ted Yu <yuzhih...@gmail.com>
Subject Re: hbase architecture doubts
Date Sun, 01 May 2016 13:44:09 GMT
For #1, in branch-1, please take a look at DefaultMemStore.java where you
would see:

  // MemStore.  Use a CellSkipListSet rather than SkipListSet because of the

  // better semantics.  The Map will overwrite if passed a key it already
had

  // whereas the Set will not add new Cell if key is same though value
might be

  // different.  Value is not important -- just make sure always same

  // reference passed.

  volatile CellSkipListSet cellSet;


  // Snapshot of memstore.  Made for flusher.

  volatile CellSkipListSet snapshot;

For #2, MemStoreFlusher#flushRegion() -> HRegion#flush() ->
HRegion#internalFlushCacheAndCommit()

Please take a look at HStore#commit().

On Sun, May 1, 2016 at 3:36 AM, Shushant Arora <shushantarora09@gmail.com>
wrote:

> 1.Does Hbase uses ConcurrentskipListMap(CSLM) to store data in memstore?
>
> 2.When mwmstore is flushed to HDFS- does it dump the memstore
> Concurrentskiplist as Hfile2? Then How does it calculates blocks out of
> CSLM and dmp them in HDFS.
>
> 3.After dumping the inmemory CSLM of memstore to HFILe does memstore
> content is discarded and if while dumping memstore any read request comes
> will it be responded by copy of memstore or discard of memstore will be
> blocked until read request is completed?
>
> 4.When a read request comes does it look in inmemory CSLM and then in
> HFile? And what is LogStructuredMerge tree and its usage in Hbase.
>
> Thanks!
>

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