Hello Kurt Deschler, Abhishek Rawat, Csaba Ringhofer, Wenzhe Zhou, Michael
Smith, Impala Public Jenkins,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/21257
to look at the new patch set (#16).
Change subject: IMPALA-12980: Translate CpuAsk into admission control slots
......................................................................
IMPALA-12980: Translate CpuAsk into admission control slots
Impala has a concept of "admission control slots" - the amount of
parallelism that should be allowed on an Impala daemon. This defaults to
the number of processors per executor and can be overridden with
-–admission_control_slots flag.
Admission control slot accounting is described in IMPALA-8998. It
computes 'slots_to_use' for each backend based on the maximum number of
instances of any fragment on that backend. This can lead to slot
underestimation and query overadmission. For example, assume an executor
node with 48 CPU cores and configured with -–admission_control_slots=48.
It is assigned 4 non-blocking query fragments, each has 12 instances
scheduled in this executor. IMPALA-8998 algorithm will request the max
instance (12) slots rather than the sum of all non-blocking fragment
instances (48). With the 36 remaining slots free, the executor can still
admit another fragment from a different query but will potentially have
CPU contention with the one that is currently running.
When COMPUTE_PROCESSING_COST is enabled, Planner will generate a CpuAsk
number that represents the cpu requirement of that query over a
particular executor group set. This number is an estimation of the
largest number of query fragment instances that can run in parallel
without waiting, given by the blocking operator analysis. Therefore, the
fragment trace that sums into that CpuAsk number can be translated into
'slots_to_use' as well, which will be a closer resemblance of maximum
parallel execution of fragment instances.
This patch adds a new query option called SLOT_COUNT_STRATEGY to control
which admission control slot accounting to use. There are two possible
values:
- LARGEST_FRAGMENT, which is the original algorithm from IMPALA-8998.
This is still the default value for the SLOT_COUNT_STRATEGY option.
- PLANNER_CPU_ASK, which will follow the fragment trace that contributes
towards CpuAsk number. This strategy will schedule more or equal
admission control slots than the LARGEST_FRAGMENT strategy.
To do the PLANNER_CPU_ASK strategy, the Planner will mark fragments that
contribute to CpuAsk as dominant fragments. It also passes
max_slot_per_executor information that it knows about the executor group
set to the scheduler.
AvgAdmissionSlotsPerExecutor counter is added to describe what Planner
thinks the average 'slots_to_use' per backend will be, which follows
this formula:
AvgAdmissionSlotsPerExecutor = ceil(CpuAsk / num_executors)
Actual 'slots_to_use' in each backend may differ than
AvgAdmissionSlotsPerExecutor, depending on what is scheduled on that
backend. 'slots_to_use' will be shown as 'AdmissionSlots' counter under
each executor profile node.
Testing:
- Update test_executors.py with AvgAdmissionSlotsPerExecutor assertion.
- Pass test_tpcds_queries.py::TestTpcdsQueryWithProcessingCost.
- Add EE test test_processing_cost.py.
- Add FE test PlannerTest#testProcessingCostPlanAdmissionSlots.
Change-Id: I338ca96555bfe8d07afce0320b3688a0861663f2
---
M be/src/scheduling/admission-controller-test.cc
M be/src/scheduling/admission-controller.cc
M be/src/scheduling/scheduler.cc
M be/src/service/query-options.cc
M be/src/service/query-options.h
M common/thrift/ImpalaService.thrift
M common/thrift/Planner.thrift
M common/thrift/Query.thrift
M fe/src/main/java/org/apache/impala/common/Id.java
M fe/src/main/java/org/apache/impala/planner/CoreCount.java
M fe/src/main/java/org/apache/impala/planner/CostingSegment.java
M fe/src/main/java/org/apache/impala/planner/PlanFragment.java
M fe/src/main/java/org/apache/impala/planner/Planner.java
M fe/src/main/java/org/apache/impala/service/Frontend.java
M fe/src/test/java/org/apache/impala/planner/PlannerTest.java
M fe/src/test/java/org/apache/impala/planner/PlannerTestBase.java
A
testdata/workloads/functional-planner/queries/PlannerTest/processing-cost-plan-admission-slots.test
A
testdata/workloads/functional-query/queries/QueryTest/processing-cost-admission-slots.test
M tests/custom_cluster/test_executor_groups.py
A tests/query_test/test_processing_cost.py
M tests/query_test/test_tpcds_queries.py
21 files changed, 1,505 insertions(+), 111 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/57/21257/16
--
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I338ca96555bfe8d07afce0320b3688a0861663f2
Gerrit-Change-Number: 21257
Gerrit-PatchSet: 16
Gerrit-Owner: Riza Suminto <riza.sumi...@cloudera.com>
Gerrit-Reviewer: Abhishek Rawat <ara...@cloudera.com>
Gerrit-Reviewer: Csaba Ringhofer <csringho...@cloudera.com>
Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com>
Gerrit-Reviewer: Kurt Deschler <kdesc...@cloudera.com>
Gerrit-Reviewer: Michael Smith <michael.sm...@cloudera.com>
Gerrit-Reviewer: Riza Suminto <riza.sumi...@cloudera.com>
Gerrit-Reviewer: Wenzhe Zhou <wz...@cloudera.com>
