Andrew Wong has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/13426 )

Change subject: KUDU-2797: the master aggregates tablet metrics
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Patch Set 1:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/13426/1/src/kudu/tserver/ts_tablet_manager.cc
File src/kudu/tserver/ts_tablet_manager.cc:

http://gerrit.cloudera.org:8080/#/c/13426/1/src/kudu/tserver/ts_tablet_manager.cc@1276
PS1, Line 1276:   CHECK_OK(replica->tablet()->CountRows(&count_rows));
> Yeah I'm curious if we can track deletes without incurring IO. I'm concerne
One idea might be to store a "rows as of last flush" in the tablet metadata or 
somesuch, that would only get updated when there is a MRS/DMS flush. The metric 
wouldn't be necessarily the most up-to-date, but we flush relatively 
frequently, so maybe it'd be good enough.

If we did that, this "CountRows()" call might be just a lookup at the cached 
value.

This approach might be even more enticing once KUDU-2204 gets implemented (I 
would like to pick that up soon, since it's becoming more and more enticing to 
store metadata for stats, configs, etc).



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Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I74406ab7cca7c22fda455c328b8ee9989a6b2d99
Gerrit-Change-Number: 13426
Gerrit-PatchSet: 1
Gerrit-Owner: helifu <[email protected]>
Gerrit-Reviewer: Adar Dembo <[email protected]>
Gerrit-Reviewer: Andrew Wong <[email protected]>
Gerrit-Reviewer: Kudu Jenkins (120)
Gerrit-Reviewer: Mike Percy <[email protected]>
Gerrit-Reviewer: helifu <[email protected]>
Gerrit-Comment-Date: Mon, 27 May 2019 22:43:42 +0000
Gerrit-HasComments: Yes

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