Tim Armstrong has uploaded a new change for review.

  http://gerrit.cloudera.org:8080/7653

Change subject: IMPALA-5677: limit clean page memory consumption
......................................................................

IMPALA-5677: limit clean page memory consumption

Adds the following flag:

  -buffer_pool_clean_pages_limit ((Advanced) Limit on bytes of clean spilled
    pages that will be accumulated in the buffer pool. Specified as number of
    bytes ('<int>[bB]?'), megabytes ('<float>[mM]'), gigabytes
    ('<float>[gG]'), or percentage of the buffer pool limit ('<int>%').
    Defaults to bytes if no unit is given..) type: string default: "10%"

This helps prevent Impala accumulating excessive amounts of clean pages,
which can cause some problems in practice:
* The OS buffer cache is squeezed, reducing I/O performance from HDFS
  and potentially reducing the ability of the OS to absorb writes from
  Impala without blocking.
* Impala process memory consumption can expand more than users or admins
  might expect. E.g. if one query is running with a mem_limit of 1GB,
  many people will be surprised if the process inflates to the full
  process limit of 100GB. Impala doesn't provide any guarantees except
  from staying within the process mem_limit, but this could be a
  surprising divergence from past behaviour.

Observability:
A new metric buffer-pool.clean-pages-limit is added.

Testing:
Added a backend test to directly test that clean pages are evicted.
Ran in a loop to flush out any flakiness.

Ran exhaustive tests.

Change-Id: Ib6b687ab4bdddf07d9d6c997ff814aa3976042f9
---
M be/src/common/global-flags.cc
M be/src/runtime/bufferpool/buffer-allocator-test.cc
M be/src/runtime/bufferpool/buffer-allocator.cc
M be/src/runtime/bufferpool/buffer-allocator.h
M be/src/runtime/bufferpool/buffer-pool-test.cc
M be/src/runtime/bufferpool/buffer-pool.cc
M be/src/runtime/bufferpool/buffer-pool.h
M be/src/runtime/bufferpool/suballocator-test.cc
M be/src/runtime/exec-env.cc
M be/src/runtime/exec-env.h
M be/src/runtime/test-env.cc
M be/src/util/memory-metrics.cc
M be/src/util/memory-metrics.h
M common/thrift/metrics.json
14 files changed, 234 insertions(+), 72 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/53/7653/1
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Gerrit-MessageType: newchange
Gerrit-Change-Id: Ib6b687ab4bdddf07d9d6c997ff814aa3976042f9
Gerrit-PatchSet: 1
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Tim Armstrong <tarmstr...@cloudera.com>

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