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https://issues.apache.org/jira/browse/HBASE-2406?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12889926#action_12889926
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Jonathan Gray commented on HBASE-2406:
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bq. Gets lack "...the ability to retrieve the latest version less than or equal
to a given timestamp, thus giving the 'latest' state of the record at a certain
point in time."
I commented on this on the blog post. This is not the case, we do support this
by setting max to be the timestamp+1
bq. Major compactions are not invisible to the user
This is hard to fix and it's not clear what "expected" behavior should be. Do
you ever re-surface a Put once it's been hidden? Seems like there's an
argument on both sides of this. If I want to keep the latest two versions, I
might have accidentally inserted a bad version, so I want to delete it and
resurface an older one. But maybe someone else has an argument that they never
want something to be able to re-appear after being shadowed?
I think the most important fix is to handle duplicate versions (ordered by
insertion time, using memstoreTS and storefile stamps).
Other stuff is less clear what the "right" answer should be. I also don't
think we can attempt to completely nail-down this stuff until we make a strong
determination about what should/should not be processed during minor
compactions. I did some preliminary benchmarking work on minor compactions a
couple months back, hoping to have an intern pick that work back up so we can
make a decision here.
> Define semantics of cell timestamps/versions
> --------------------------------------------
>
> Key: HBASE-2406
> URL: https://issues.apache.org/jira/browse/HBASE-2406
> Project: HBase
> Issue Type: Task
> Components: documentation
> Reporter: Todd Lipcon
> Priority: Critical
> Fix For: 0.90.0
>
>
> There is a lot of general confusion over the semantics of the cell timestamp.
> In particular, a couple questions that often come up:
> - If multiple writes to a cell have the same timestamp, are all versions
> maintained or just the last?
> - Is it OK to write cells in a non-increasing timestamp order?
> Let's discuss, figure out what semantics make sense, and then move towards
> (a) documentation, (b) unit tests that prove we have those semantics.
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