[kudu-CR] KUDU-1807 (part 1): deprecate GetTableSchema.create table done

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

Hello Dan Burkert, Todd Lipcon,

I'd like you to reexamine a change.  Please visit

    http://gerrit.cloudera.org:8080/8027

to look at the new patch set (#2).

Change subject: KUDU-1807 (part 1): deprecate GetTableSchema.create_table_done
......................................................................

KUDU-1807 (part 1): deprecate GetTableSchema.create_table_done

Improving IsCreateInProgress performance in the master is very challenging
due to the myriad of locks in play. A simpler alternative would be to get it
off any critical paths. It's currently called by the IsCreateTableDone and
GetTableSchema RPCs. The former makes sense but the latter does not: if we
need to know whether a table has been created, well, that's what the
IsCreateTableDone RPC is for.

So, does anyone use the "is table done creating" aspect of GetTableSchema?
The C++ client doesn't, but the Java client does. As luck would have it, the
Java client is already written to fall back to IsCreateTableDone if
GetTableSchema says the table is still being created, which means we can
safely modify the master to always return false in this field without
breaking old Java clients.

Future patches will change the behavior of the Java client and remove the
create_table_done field altogether. For now, the existence of this
deprecation patch helps to ensure that the Java client does, in fact, work
properly if the field's value is always false.

Change-Id: Ia33bbb2abaabb97db1613d442a7d065710048cc2
---
M src/kudu/integration-tests/registration-test.cc
M src/kudu/master/catalog_manager.cc
M src/kudu/master/master.proto
3 files changed, 3 insertions(+), 16 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/kudu refs/changes/27/8027/2
-- 
To view, visit http://gerrit.cloudera.org:8080/8027
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Ia33bbb2abaabb97db1613d442a7d065710048cc2
Gerrit-PatchSet: 2
Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-Owner: Adar Dembo <ad...@cloudera.com>
Gerrit-Reviewer: Adar Dembo <ad...@cloudera.com>
Gerrit-Reviewer: Dan Burkert <da...@apache.org>
Gerrit-Reviewer: Jean-Daniel Cryans <jd...@apache.org>
Gerrit-Reviewer: Todd Lipcon <to...@apache.org>