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https://issues.apache.org/jira/browse/HBASE-16417?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15662618#comment-15662618
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Anoop Sam John commented on HBASE-16417:
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It is not just TS being applied by client issue. (Yes that is also one and
when we are sure that all TS applied by server only and it is strictly
increasing some other optimizations also possible. There is some jira around
that. Forgot id. But LarsH raised that)
The main thing is that when we do a row get, how u will know that u have done
with all the columns in that row? HBase being a CF oriented NoSQL, we don't
know the columns within a CF and it can differ from row to row. But when we
know the column qualifiers always and specify in Get, and we look for only one
version and we are sure abt the TS increasing nature, ya the optimization is
possible. The ColumnTracker always track and allow only the given columns in
Get are being selected. And the other 2 also stands, then we can do this
optimization I believe.. I did not do any code read or deep analysis.. I
get ur point also.. In usecase like u described, it is some thing to really
think abt
{code}
/**
* Special scanner, currently used for increment operations to
* allow additional server-side arguments for Scan operations.
* <p>
* Rather than adding new options/parameters to the public Scan API, this new
* class has been created.
* <p>
* Supports adding an option to only read from the MemStore with
* {@link #checkOnlyMemStore()} or to only read from StoreFiles with
* {@link #checkOnlyStoreFiles()}.
*/
@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)
public class InternalScan extends Scan {
{code}
This is not public client side exposed. Only can be used within CPs. JFYI
> In-Memory MemStore Policy for Flattening and Compactions
> --------------------------------------------------------
>
> Key: HBASE-16417
> URL: https://issues.apache.org/jira/browse/HBASE-16417
> Project: HBase
> Issue Type: Sub-task
> Reporter: Anastasia Braginsky
> Assignee: Eshcar Hillel
> Fix For: 2.0.0
>
> Attachments: HBASE-16417-benchmarkresults-20161101.pdf,
> HBASE-16417-benchmarkresults-20161110.pdf
>
>
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