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From "Sailesh Mukil (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-4516: Don't hold process wide lock connection to sessions map lock while cancelling queries
Date Tue, 22 Nov 2016 02:59:35 GMT
Sailesh Mukil has uploaded a new change for review.

  http://gerrit.cloudera.org:8080/5173

Change subject: IMPALA-4516: Don't hold process wide lock connection_to_sessions_map_lock_
while cancelling queries
......................................................................

IMPALA-4516: Don't hold process wide lock connection_to_sessions_map_lock_ while cancelling
queries

We hold the connection_to_sessions_map_lock_ while closing multiple
sessions, which could map to a large number of queries, which means an
even larger number of fragments. We hold this process wide lock and a
series of other locks while sending cancel RPCs to all the fragments
that fall under the above mentioned category.

This could slow down the responsiveness to the client by the daemon.
Moreover, holding the lock is unnecessary and we can do without it.

This patch fixes this path by dropping the lock before we call
CloseSessionInternal().

Change-Id: I9fe37955027ad9fec3fdbbbcb199245c79bcac71
---
M be/src/service/impala-server.cc
1 file changed, 18 insertions(+), 8 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/73/5173/1
-- 
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Gerrit-MessageType: newchange
Gerrit-Change-Id: I9fe37955027ad9fec3fdbbbcb199245c79bcac71
Gerrit-PatchSet: 1
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Sailesh Mukil <sailesh@cloudera.com>

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