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https://issues.apache.org/jira/browse/PIG-4626?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Rohini Palaniswamy updated PIG-4626:
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Description:
tez.task.scale.memory.reserve-fraction is 0.3 by default which assumes 70% of
memory is available for io.sort.mb. If map is configured as 1G Xmx and
io.sort.mb as 256MB, and there is group by on 3 different keys it has 3
different outputs and Tez's WeightedScalingMemoryDistributor allocates 256MB to
each of the outputs which leaves very less memory for Pig and POPartialAgg
(which requires 20% of memory) and sometime leads to OOM. This also causes
SpillableMemoryManager to be invoked often as its threshold is set to 70% of
memory.
Need to set tez.task.scale.memory.reserve-fraction as 0.5 for all pig jobs and
0.6 in case there is POPartialAgg in combiner plan.
was:
tez.task.scale.memory.reserve-fraction is 0.3 by default which assumes 70% of
memory is available for io.sort.mb. If map is configured as 1G Xmx and
io.sort.mb as 256MB, and there is group by on 3 different keys it has 3
different outputs and Tez's WeightedScalingMemoryDistributor allocates 256MB to
each of the outputs which leaves very less memory for Pig and POPartialAgg
(which requires 20% of memory) and sometime leads to OOM. This also causes
SpillableMemoryManager to be invoked often as its threshold is set to 70% of
memory.
Need to set tez.task.scale.memory.reserve-fraction as 0.5 for all pig jobs and
0.4 in case there is POPartialAgg in combiner plan.
> [Pig on Tez] OOM in case of multiple outputs and POPartialAgg
> -------------------------------------------------------------
>
> Key: PIG-4626
> URL: https://issues.apache.org/jira/browse/PIG-4626
> Project: Pig
> Issue Type: Bug
> Reporter: Rohini Palaniswamy
> Assignee: Rohini Palaniswamy
> Fix For: 0.16.0, 0.15.1
>
>
> tez.task.scale.memory.reserve-fraction is 0.3 by default which assumes 70%
> of memory is available for io.sort.mb. If map is configured as 1G Xmx and
> io.sort.mb as 256MB, and there is group by on 3 different keys it has 3
> different outputs and Tez's WeightedScalingMemoryDistributor allocates 256MB
> to each of the outputs which leaves very less memory for Pig and POPartialAgg
> (which requires 20% of memory) and sometime leads to OOM. This also causes
> SpillableMemoryManager to be invoked often as its threshold is set to 70% of
> memory.
> Need to set tez.task.scale.memory.reserve-fraction as 0.5 for all pig jobs
> and 0.6 in case there is POPartialAgg in combiner plan.
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