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From ramkrishna vasudevan <ramkrishna.s.vasude...@gmail.com>
Subject Re: StoreScanner created for memstore flush should be bothered about updated readers?
Date Fri, 31 Jan 2014 04:56:35 GMT
Thanks Enis for your reply.  The effect of resetting the heap is that we
would start reading those files under the StoreScanner and start doing the
comparison with the KVs in the memstore scanner.
Ideally this comparison is not needed and this can be avoided by not
allowing the storescanners getting added to the heap.
(Will this flush the KVs from the file once again? Need to verify that.
Should not happen ideally.)
I can file a JIRA for this and discuss there.

Regards
Ram


On Fri, Jan 31, 2014 at 7:54 AM, Enis Söztutar <enis.soz@gmail.com> wrote:

> It seems you are right. I think only if a concurrent compaction finishes
> the memstore scanner would be affected right?
>
> How big is the affect for resetting the KVHeap ?
>
> Enis
>
>
> On Thu, Jan 30, 2014 at 11:48 AM, ramkrishna vasudevan <
> ramkrishna.s.vasudevan@gmail.com> wrote:
>
> > Hi All
> >
> > In case of flush we create a memstore flusher which in turn creates a
> >  StoreScanner backed by a Single ton MemstoreScanner.
> >
> > But this scanner also registers for any updates in the reader in the
> > HStore.  Is this needed?
> > If this happens then any update on the reader may nullify the current
> heap
> > and the entire Scanner Stack is reset, but this time with the other
> > scanners for all the files that satisfies the last top key.  So the flush
> > that happens on the memstore holds the storefile scanners also in the
> heap
> > that was recreated but originally the intention was to create a scanner
> on
> > the memstore alone.
> >
> > Am i missing something here?  Or what i observed is right?  If so, then I
> > feel that this step can be avoided.
> >
> > Regards
> > Ram
> >
>

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