Hello Tim Armstrong,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/8060
to look at the new patch set (#2).
Change subject: IMPALA-5926: Avoid printing expensive stack when closing a
session
......................................................................
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
---
M be/src/service/impala-server.cc
1 file changed, 1 insertion(+), 1 deletion(-)
git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/60/8060/2
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I9d0ca485dd17bca758d916040745288c1a20c69f
Gerrit-PatchSet: 2
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Mostafa Mokhtar <[email protected]>
Gerrit-Reviewer: Alex Behm <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
