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From bhara...@apache.org
Subject [1/4] incubator-impala git commit: IMPALA-5926: Avoid printing expensive stack when closing a session
Date Fri, 15 Sep 2017 04:33:38 GMT
Repository: incubator-impala
Updated Branches:
  refs/heads/master 5325b1c07 -> 0a54cb5ec


IMPALA-5926: Avoid printing expensive stack when closing a session

When conducting high concurrency tests for short running queries
 noticed that queries are spending lots of time in Unregister query.
Investigation showed that CloseSessionInternal calls
status("Session closed") which unnecessarily prints the stack
to the log which is expensive and not required, refer to IMPALA-5275.

The fix uses Expected(const std::string& error_msg) which doesn't
print the stack.

Table below summarizes speedup for highly selective scan query.

+-----------+--------------------------+---------------------+---------+
| Num users | Baseline Queries/minutes | Fix Queries/minutes | Speedup |
+-----------+--------------------------+---------------------+---------+
| 1         | 19                       | 24                  | 1.23x   |
| 2         | 41                       | 48                  | 1.17x   |
| 4         | 71                       | 91                  | 1.28x   |
| 8         | 96                       | 161                 | 1.67x   |
| 16        | 117                      | 226                 | 1.92x   |
| 32        | 140                      | 266                 | 1.90x   |
| 64        | 174                      | 269                 | 1.54x   |
| 128       | 202                      | 265                 | 1.31x   |
+-----------+--------------------------+---------------------+---------+

Change-Id: I9d0ca485dd17bca758d916040745288c1a20c69f
Reviewed-on: http://gerrit.cloudera.org:8080/8060
Reviewed-by: Alex Behm <alex.behm@cloudera.com>
Tested-by: Impala Public Jenkins


Project: http://git-wip-us.apache.org/repos/asf/incubator-impala/repo
Commit: http://git-wip-us.apache.org/repos/asf/incubator-impala/commit/3e73ce2c
Tree: http://git-wip-us.apache.org/repos/asf/incubator-impala/tree/3e73ce2c
Diff: http://git-wip-us.apache.org/repos/asf/incubator-impala/diff/3e73ce2c

Branch: refs/heads/master
Commit: 3e73ce2c4d2a591ef91291d520d4cb3e1d69b092
Parents: 5325b1c
Author: mmokhtar <mmokhtar@cloudera.com>
Authored: Wed Sep 13 16:03:56 2017 -0700
Committer: Impala Public Jenkins <impala-public-jenkins@gerrit.cloudera.org>
Committed: Thu Sep 14 16:27:06 2017 +0000

----------------------------------------------------------------------
 be/src/service/impala-server.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/3e73ce2c/be/src/service/impala-server.cc
----------------------------------------------------------------------
diff --git a/be/src/service/impala-server.cc b/be/src/service/impala-server.cc
index 7eae5b1..8ba2894 100644
--- a/be/src/service/impala-server.cc
+++ b/be/src/service/impala-server.cc
@@ -1113,7 +1113,7 @@ Status ImpalaServer::CloseSessionInternal(const TUniqueId& session_id,
         session_state->inflight_queries.end());
   }
   // Unregister all open queries from this session.
-  Status status("Session closed");
+  Status status = Status::Expected("Session closed");
   for (const TUniqueId& query_id: inflight_queries) {
     // TODO: deal with an error status
     discard_result(UnregisterQuery(query_id, false, &status));


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