[kudu-CR] KUDU-2986 p2: hide the live row count of table metrics

["helifu (Code Review)" <ge...@cloudera.org>]

helifu has posted comments on this change. ( http://gerrit.cloudera.org:8080/14601 )

Change subject: KUDU-2986 p2: hide the live row count of table metrics
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Patch Set 1:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/14601/1/src/kudu/master/catalog_manager.cc
File src/kudu/master/catalog_manager.cc:

http://gerrit.cloudera.org:8080/#/c/14601/1/src/kudu/master/catalog_manager.cc@5592
PS1, Line 5592:       metrics_->HideLiveRowCount(metric_entity_);
> When old partitions have been dropped, the metric should not be hidden, rig
Yep, you are correct. Thanks for reminding. I have changed to another solution. Please take a look.^_^


http://gerrit.cloudera.org:8080/#/c/14601/1/src/kudu/master/table_metrics.cc
File src/kudu/master/table_metrics.cc:

http://gerrit.cloudera.org:8080/#/c/14601/1/src/kudu/master/table_metrics.cc@65
PS1, Line 65:   METRIC_live_row_count.InstantiateInvalid(entity, 0);
> Why this and not on_disk_size->InvalidateEpoch()?
It seems that neither InstantiateInvalid() nor InvalidateEpoch() is the best solution, because this design will introduce other problems. For example, if we hide the metric(live_row_count), then we have to ignore the values while it is invisible. But, if we recover this metric(all of the tablets support live row count), how can we ask the tservers to report the stats if there is no any diff on the tserver? Thus, I turn to use InstantiateFunctionGauge instead. All of the stats should be kept in the TableMetrics.



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Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I4c7ac5ca7e8ce9dcc37035a7bc46ca69060d6533
Gerrit-Change-Number: 14601
Gerrit-PatchSet: 1
Gerrit-Owner: helifu <hz...@corp.netease.com>
Gerrit-Reviewer: Adar Dembo <ad...@cloudera.com>
Gerrit-Reviewer: Alexey Serbin <as...@cloudera.com>
Gerrit-Reviewer: Kudu Jenkins (120)
Gerrit-Reviewer: Yifan Zhang <ch...@163.com>
Gerrit-Reviewer: helifu <hz...@corp.netease.com>
Gerrit-Comment-Date: Fri, 01 Nov 2019 08:15:51 +0000
Gerrit-HasComments: Yes