Adar Dembo has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/14222 )

Change subject: KUDU-2069 p4: stop replication from failed servers in 
maintenance mode
......................................................................


Patch Set 2:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/14222/2/src/kudu/master/ts_manager.h
File src/kudu/master/ts_manager.h:

http://gerrit.cloudera.org:8080/#/c/14222/2/src/kudu/master/ts_manager.h@94
PS2, Line 94:   void GetWhitelistedUuids(std::unordered_set<std::string>* 
uuids) const;
> Not sure I understand why that would be any better than generating the list
If O(num tservers in maintenance mode) is relatively high, GetWhitelistedUuids 
will take a lot of locks. The acquisitions are one-at-a-time, but it's possible 
it's still computationally more expensive than ~3 TSManager lookups in 
ShouldAddReplica. With the change to only call GetWhitelistedUuids once per 
heartbeat vs. one per reported tablet, it's probably better than lookups in 
ShouldAddReplica _for full reports_. But what about incremental reports, which 
may only include a few tablets?

As for the name, maybe it'd be clearer if you shifted the complexity to 
ShouldAddReplica by calling the method GetMaintenanceModeTServers. Then 
ShouldAddReplica gets to explain how/why MM affects rereplication, but since 
that area of code is already dealing with that concept, it's more natural for 
the full explanation to also live there.



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Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I9a63b55011d16900c0d27eac0eb75880074204db
Gerrit-Change-Number: 14222
Gerrit-PatchSet: 2
Gerrit-Owner: Andrew Wong <[email protected]>
Gerrit-Reviewer: Adar Dembo <[email protected]>
Gerrit-Reviewer: Alexey Serbin <[email protected]>
Gerrit-Reviewer: Andrew Wong <[email protected]>
Gerrit-Reviewer: Hao Hao <[email protected]>
Gerrit-Reviewer: Kudu Jenkins (120)
Gerrit-Comment-Date: Mon, 16 Sep 2019 23:12:46 +0000
Gerrit-HasComments: Yes

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