Yingchun Lai has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/18053 )

Change subject: [bootstrap] Speedup tablet bootstrap
......................................................................


Patch Set 19:

(6 comments)

http://gerrit.cloudera.org:8080/#/c/18053/8//COMMIT_MSG
Commit Message:

http://gerrit.cloudera.org:8080/#/c/18053/8//COMMIT_MSG@18
PS8, Line 18: --num_tablets_to_open_simultaneously from default 1 to 8
> Can you show the actual numbers? Did you use the same num_tablets_to_open_s
Commit message updated.
Yes I tested both cases, but before this patch, 
--num_tablets_to_open_simultaneously is not used for _table metadata load_ 
procedure, the test is meanless.


http://gerrit.cloudera.org:8080/#/c/18053/4/src/kudu/tablet/tablet_bootstrap.cc
File src/kudu/tablet/tablet_bootstrap.cc:

http://gerrit.cloudera.org:8080/#/c/18053/4/src/kudu/tablet/tablet_bootstrap.cc@826
PS4, Line 826: if (b.term() == a.term() &&
> I don't think this makes the code clearer.
Done


http://gerrit.cloudera.org:8080/#/c/18053/8/src/kudu/tserver/ts_tablet_manager-test.cc
File src/kudu/tserver/ts_tablet_manager-test.cc:

http://gerrit.cloudera.org:8080/#/c/18053/8/src/kudu/tserver/ts_tablet_manager-test.cc@416
PS8, Line 416:   const int64_t kTabletCount = 
FLAGS_startup_benchmark_tablet_count_for_testing;
> Why 8 threads specifically?
I‘ve removed this thread pool, the pool is meanless here.


http://gerrit.cloudera.org:8080/#/c/18053/8/src/kudu/tserver/ts_tablet_manager-test.cc@436
PS8, Line 436:   FLAGS_minloglevel = 2;
> Why do we skip opening the tablet? Shouldn't we measure the time it takes t
Because this patch and this benchmark is only for tablet _metadata_ load 
procedure, the whole tablet bootstrap include tablet metadata load, open, 
replay wals, consensus, etc. The other procedures will cost much time, but I 
don't care for this benchmark itself, so I want to skip them.


http://gerrit.cloudera.org:8080/#/c/18053/8/src/kudu/tserver/ts_tablet_manager-test.cc@437
PS8, Line 437: }
> Why are we injecting latency in a benchmark?
I'm going to simulate a bad disk IO latency, to prove this patch's optimization 
works indeed.


http://gerrit.cloudera.org:8080/#/c/18053/15/src/kudu/tserver/ts_tablet_manager.cc
File src/kudu/tserver/ts_tablet_manager.cc:

http://gerrit.cloudera.org:8080/#/c/18053/15/src/kudu/tserver/ts_tablet_manager.cc@499
PS15, Line 499: for (int i = 0; i < tablet_ids.s
> nit: since 'tablet_ids' is already populated when 'metas' is constructed, i
Done



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Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I816417d2d4c24014edb6b2a40c060f29e37ae219
Gerrit-Change-Number: 18053
Gerrit-PatchSet: 19
Gerrit-Owner: Yingchun Lai <[email protected]>
Gerrit-Reviewer: Alexey Serbin <[email protected]>
Gerrit-Reviewer: Attila Bukor <[email protected]>
Gerrit-Reviewer: Kudu Jenkins (120)
Gerrit-Reviewer: Tidy Bot (241)
Gerrit-Reviewer: Yingchun Lai <[email protected]>
Gerrit-Comment-Date: Fri, 03 Dec 2021 07:58:58 +0000
Gerrit-HasComments: Yes

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