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https://issues.apache.org/jira/browse/HBASE-14070?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15378383#comment-15378383
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Enis Soztutar commented on HBASE-14070:
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bq. Referring to the Description on RB link. Why are Meta Tables not HLC ? What
is the reason for it ?
I think it is a typo on my end. It should have read:
- Meta table is *now* HLC and all tables by default are HLC.
The patch contains this:
{code}
metaDescriptor.setTimestampType(Timestamp.HLC);
{code}
> Hybrid Logical Clocks for HBase
> -------------------------------
>
> Key: HBASE-14070
> URL: https://issues.apache.org/jira/browse/HBASE-14070
> Project: HBase
> Issue Type: New Feature
> Reporter: Enis Soztutar
> Assignee: Sai Teja Ranuva
> Attachments: HybridLogicalClocksforHBaseandPhoenix.docx,
> HybridLogicalClocksforHBaseandPhoenix.pdf
>
>
> HBase and Phoenix uses systems physical clock (PT) to give timestamps to
> events (read and writes). This works mostly when the system clock is strictly
> monotonically increasing and there is no cross-dependency between servers
> clocks. However we know that leap seconds, general clock skew and clock drift
> are in fact real.
> This jira proposes using Hybrid Logical Clocks (HLC) as an implementation of
> hybrid physical clock + a logical clock. HLC is best of both worlds where it
> keeps causality relationship similar to logical clocks, but still is
> compatible with NTP based physical system clock. HLC can be represented in
> 64bits.
> A design document is attached and also can be found here:
> https://docs.google.com/document/d/1LL2GAodiYi0waBz5ODGL4LDT4e_bXy8P9h6kWC05Bhw/edit#
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