Adar Dembo has posted comments on this change.

Change subject: KUDU-1726: Avoid fsync-per-block in tablet copy
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Patch Set 1:

(8 comments)

Mike should probably review this too.

http://gerrit.cloudera.org:8080/#/c/7701/1//COMMIT_MSG
Commit Message:

PS1, Line 9: with
Nit: into


PS1, Line 11: table
tablet


PS1, Line 11: sync
synced


PS1, Line 13: I did a manual test to copy tablet with size of ~37GB.
            : With this change, the operation time dropped down from ~718s
            : to ~523s.
We talked about this in person a little bit, but could you provide more details 
about the testing set up? Please specify how many tservers were involved. If 
just one, specify the OS, the filesystem, the disk setup, etc.


http://gerrit.cloudera.org:8080/#/c/7701/1/src/kudu/tserver/tablet_copy_client-test.cc
File src/kudu/tserver/tablet_copy_client-test.cc:

Line 196: TEST_F(TabletCopyClientTest, TestDownloadAllBlocks) {
Maybe as part of this test we could verify that the number of fsyncs due to 
block downloading was some number we expect? We don't currently have metrics 
for fsyncs but that's something we could feasibly add (to the LogBlockManager 
or perhaps even to the file implementations in env_posix.cc).


http://gerrit.cloudera.org:8080/#/c/7701/1/src/kudu/tserver/tablet_copy_client.h
File src/kudu/tserver/tablet_copy_client.h:

Line 27: #include "kudu/fs/block_manager.h"
Why do you need this? Can't you forward declare BlockTransaction?


PS1, Line 164: belong
belonging


Line 177:   // Data block is opened with options so that it will fsync() on 
close.
Update this (and maybe the entire comment).


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Gerrit-MessageType: comment
Gerrit-Change-Id: I7534699f589c7060ffe32d7ac67546476cf21e76
Gerrit-PatchSet: 1
Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-Owner: Hao Hao <[email protected]>
Gerrit-Reviewer: Adar Dembo <[email protected]>
Gerrit-Reviewer: Kudu Jenkins
Gerrit-HasComments: Yes

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