[kudu-CR] Add a way to pin clean time advancement

["David Ribeiro Alves (Code Review)" <ge...@cloudera.org>]

Hello Alexey Serbin, Kudu Jenkins, Andrew Wong, Hao Hao, Todd Lipcon, 

I'd like you to reexamine a change. Please visit

    http://gerrit.cloudera.org:8080/9641

to look at the new patch set (#7).

Change subject: Add a way to pin clean time advancement
......................................................................

Add a way to pin clean time advancement

In order to make OpId/Timestamp assignment to transactions
atomic, during the prepare phase, we need to let consensus
assign the timestamp, before starting a transaction in
mvcc. However we also need to make sure that clean time is
not advanced past the possible timestamps assigned.

This patch add a pin to clean time advancement that acts
much like safe time, in the sense that it doesn't allow
clean time to be advanced past it.

This also adds a way to create and delete a pin within
a scope in a raii way.

Change-Id: If863d28016aee98672d94ec5dc8a8630e1cbf5c8
---
M src/kudu/tablet/mvcc-test.cc
M src/kudu/tablet/mvcc.cc
M src/kudu/tablet/mvcc.h
3 files changed, 75 insertions(+), 26 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/kudu refs/changes/41/9641/7
-- 
To view, visit http://gerrit.cloudera.org:8080/9641
To unsubscribe, visit http://gerrit.cloudera.org:8080/settings

Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: If863d28016aee98672d94ec5dc8a8630e1cbf5c8
Gerrit-Change-Number: 9641
Gerrit-PatchSet: 7
Gerrit-Owner: David Ribeiro Alves <da...@gmail.com>
Gerrit-Reviewer: Alexey Serbin <as...@cloudera.com>
Gerrit-Reviewer: Andrew Wong <aw...@cloudera.com>
Gerrit-Reviewer: David Ribeiro Alves <da...@gmail.com>
Gerrit-Reviewer: Hao Hao <ha...@cloudera.com>
Gerrit-Reviewer: Kudu Jenkins
Gerrit-Reviewer: Todd Lipcon <to...@apache.org>