[
https://issues.apache.org/jira/browse/BEAM-10409?focusedWorklogId=473068&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-473068
]
ASF GitHub Bot logged work on BEAM-10409:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 20/Aug/20 20:25
Start Date: 20/Aug/20 20:25
Worklog Time Spent: 10m
Work Description: yifanmai commented on a change in pull request #12185:
URL: https://github.com/apache/beam/pull/12185#discussion_r474252169
##########
File path:
sdks/python/apache_beam/runners/portability/fn_api_runner/translations.py
##########
@@ -690,6 +692,196 @@ def fix_side_input_pcoll_coders(stages, pipeline_context):
return stages
+def pack_combiners(stages, context):
+ # type: (Iterable[Stage], TransformContext) -> Iterator[Stage]
+ """Packs sibling CombinePerKey stages into a single CombinePerKey.
+
+ If CombinePerKey stages have a common input, one input each, and one output
+ each, pack the stages into a single stage that runs all CombinePerKeys and
+ outputs resulting tuples to a new PCollection. A subsequent stage unpacks
+ tuples from this PCollection and sends them to the original output
+ PCollections.
+ """
+
+ class _UnpackFn(core.DoFn):
+ """A DoFn that unpacks a packed to multiple tagged outputs.
+
+ Example:
+ tags = (T1, T2, ...)
+ input = (K, (V1, V2, ...))
+ output = TaggedOutput(T1, (K, V1)), TaggedOutput(T2, (K, V1)), ...
+ """
+
+ def __init__(self, tags):
+ self._tags = tags
+
+ def process(self, element):
+ key, values = element
+ return [
+ core.pvalue.TaggedOutput(tag, (key, value))
+ for tag, value in zip(self._tags, values)
+ ]
+
+ def _get_fallback_coder_id():
+ return context.add_or_get_coder_id(
+ coders.registry.get_coder(object).to_runner_api(None))
+
+ def _get_component_coder_id_from_kv_coder(coder, index):
+ assert index < 2
+ if coder.spec.urn == common_urns.coders.KV.urn and len(
+ coder.component_coder_ids) == 2:
+ return coder.component_coder_ids[index]
+ return _get_fallback_coder_id()
+
+ def _get_key_coder_id_from_kv_coder(coder):
+ return _get_component_coder_id_from_kv_coder(coder, 0)
+
+ def _get_value_coder_id_from_kv_coder(coder):
+ return _get_component_coder_id_from_kv_coder(coder, 1)
+
+ def _try_fuse_stages(a, b):
+ if a.can_fuse(b, context):
+ return a.fuse(b)
+ else:
+ raise ValueError
+
+ # Group stages by parent, yielding ineligible stages.
+ combine_stages_by_input_pcoll_id = collections.defaultdict(list)
+ for stage in stages:
+ transform = only_transform(stage.transforms)
+ if transform.spec.urn == common_urns.composites.COMBINE_PER_KEY.urn and
len(
+ transform.inputs) == 1 and len(transform.outputs) == 1:
+ input_pcoll_id = only_element(transform.inputs.values())
+ combine_stages_by_input_pcoll_id[input_pcoll_id].append(stage)
+ else:
+ yield stage
+
+ for input_pcoll_id, packable_stages in
combine_stages_by_input_pcoll_id.items(
+ ):
+ # Yield stage and continue if it has no siblings.
+ if len(packable_stages) == 1:
+ yield packable_stages[0]
+ continue
+
+ transforms = [only_transform(stage.transforms) for stage in
packable_stages]
+ combine_payloads = [
+ proto_utils.parse_Bytes(transform.spec.payload,
+ beam_runner_api_pb2.CombinePayload)
+ for transform in transforms
+ ]
+
+ # Yield stages and continue if they cannot be packed.
+ try:
+ # Fused stage is used as template and is not yielded.
+ fused_stage = functools.reduce(_try_fuse_stages, packable_stages)
+ merged_transform_environment_id = functools.reduce(
+ Stage._merge_environments,
+ [transform.environment_id or None for transform in transforms])
+ # Combiner packing only supports Python CombineFns.
+ for combine_payload in combine_payloads:
+ if combine_payload.combine_fn.urn != python_urns.PICKLED_COMBINE_FN:
+ raise ValueError('Combiner packing only supports Python CombineFns')
+ except ValueError:
+ for stage in packable_stages:
+ yield stage
+ continue
+
+ output_pcoll_ids = [
+ only_element(transform.outputs.values()) for transform in transforms
+ ]
+
+ # Build accumulator coder for (acc1, acc2, ...)
+ accumulator_coder_ids = [
+ combine_payload.accumulator_coder_id
+ for combine_payload in combine_payloads
+ ]
+ tuple_accumulator_coder_id = context.add_or_get_coder_id(
+ beam_runner_api_pb2.Coder(
+ spec=beam_runner_api_pb2.FunctionSpec(
+ urn=common_urns.coders.KV.urn),
Review comment:
Done.
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
Issue Time Tracking
-------------------
Worklog Id: (was: 473068)
Time Spent: 4h 20m (was: 4h 10m)
> Add combiner packing to graph optimizer phases
> ----------------------------------------------
>
> Key: BEAM-10409
> URL: https://issues.apache.org/jira/browse/BEAM-10409
> Project: Beam
> Issue Type: Improvement
> Components: runner-core
> Reporter: Yifan Mai
> Assignee: Yifan Mai
> Priority: P2
> Time Spent: 4h 20m
> Remaining Estimate: 0h
>
> Some use cases of Beam (e.g. [TensorFlow
> Transform|https://github.com/tensorflow/transform]) create thousands of
> Combine stages with a common parent. The large number of stages can cause
> performance issues on some runners. To alleviate, a graph optimization phase
> could be added to the translations module that packs compatible Combine
> stages into a single stage.
> The graph optimization for CombinePerKey would work as follows: If
> CombinePerKey stages have a common input, one input each, and one output
> each, pack the stages into a single stage that runs all CombinePerKeys and
> outputs resulting tuples to a new PCollection. A subsequent stage unpacks
> tuples from this PCollection and sends them to the original output
> PCollections.
> There is an additional issue with supporting this for CombineGlobally:
> because of the intermediate KeyWithVoid stage between the CombinePerKey
> stages and the input stage, the CombinePerKey stages do not have a common
> input stage, and cannot be packed. To support CombineGlobally, a common
> sibling elimination graph optimization phase can be used to combine the
> KeyWithVoid stages. After this, the CombinePerKey stages would have a common
> input and can be packed.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
