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https://issues.apache.org/jira/browse/HBASE-4344?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13112274#comment-13112274
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Ted Yu commented on HBASE-4344:
-------------------------------
This is due to KeyValue not remembering whether MemstoreTS is included.
One trick is to distinguish existence of MemstoreTS through a special value
(e.g. -1).
Currently we have:
{code}
// default value is 0, aka DNC
private long memstoreTS = 0;
{code}
We can use -1 to distinguish the absence of MemstoreTS.
However, getMemstoreTS() would always return 0 if memstoreTS carries -1.
TestStoreFile passes with the above trick.
> Persist memstoreTS to disk
> --------------------------
>
> Key: HBASE-4344
> URL: https://issues.apache.org/jira/browse/HBASE-4344
> Project: HBase
> Issue Type: Sub-task
> Reporter: Amitanand Aiyer
> Assignee: Amitanand Aiyer
> Fix For: 0.89.20100924
>
> Attachments: 4344-v2.txt, 4344-v4.txt, patch-2
>
>
> Atomicity can be achieved in two ways -- (i) by using a multiversion
> concurrency system (MVCC), or (ii) by ensuring that "new" writes do not
> complete, until the "old" reads complete.
> Currently, Memstore uses something along the lines of MVCC (called RWCC for
> read-write-consistency-control). But, this mechanism is not incorporated for
> the key-values written to the disk, as they do not include the memstore TS.
> Let us make the two approaches be similar, by persisting the memstoreTS along
> with the key-value when it is written to the disk.
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