Hello Michael Ho,

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

    http://gerrit.cloudera.org:8080/7408

to look at the new patch set (#5).

Change subject: IMPALA-5417: make I/O buffer queue fixed-size
......................................................................

IMPALA-5417: make I/O buffer queue fixed-size

This removes the dynamically-varying queue size behaviour in the I/O
manager. The motivation is to bound resource consumption of scans
and make it possible to reserve memory for I/O buffers upfront.

Does some cleanup/documentation of the locking policy. Fix some cases
in ScanRange::GetNext() where members documented as being protected by
ScanRange::lock_ were accessed without holding it. I think the races
were either benign or prevented by holding DiskIoRequestContext::lock_
in practice.

Testing:
Ran exhaustive build.

Perf:
Ran the full set of workloads (TPC-H, TPC-DS, targeted) on a 16 node
cluster. Everything was within normal variance.

Change-Id: If7cc3f7199f5320db00b7face97a96cdadb6f83f
---
M be/src/runtime/disk-io-mgr-internal.h
M be/src/runtime/disk-io-mgr-reader-context.cc
M be/src/runtime/disk-io-mgr-scan-range.cc
M be/src/runtime/disk-io-mgr-test.cc
M be/src/runtime/disk-io-mgr.cc
M be/src/runtime/disk-io-mgr.h
6 files changed, 290 insertions(+), 335 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/08/7408/5
-- 
To view, visit http://gerrit.cloudera.org:8080/7408
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: If7cc3f7199f5320db00b7face97a96cdadb6f83f
Gerrit-PatchSet: 5
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Tim Armstrong <tarmstr...@cloudera.com>
Gerrit-Reviewer: Michael Ho
Gerrit-Reviewer: Michael Ho <k...@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstr...@cloudera.com>

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