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https://issues.apache.org/jira/browse/BEAM-8537?focusedWorklogId=370084&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-370084
]
ASF GitHub Bot logged work on BEAM-8537:
----------------------------------------
Author: ASF GitHub Bot
Created on: 10/Jan/20 21:18
Start Date: 10/Jan/20 21:18
Worklog Time Spent: 10m
Work Description: boyuanzz commented on pull request #10375: [BEAM-8537]
Provide WatermarkEstimator to track watermark
URL: https://github.com/apache/beam/pull/10375#discussion_r365434163
##########
File path: sdks/python/apache_beam/runners/common.py
##########
@@ -771,22 +810,33 @@ def try_split(self, fraction):
# Temporary workaround for [BEAM-7473]: get current_watermark before
# split, in case watermark gets advanced before getting split results.
# In worst case, current_watermark is always stale, which is ok.
- if self.watermark_estimator:
- current_watermark = self.watermark_estimator.current_watermark()
- else:
- current_watermark = None
+ current_watermark = None
split = restriction_tracker.try_split(fraction)
if split:
primary, residual = split
element = self.current_windowed_value.value
restriction_provider = self.signature.get_restriction_provider()
primary_size = restriction_provider.restriction_size(element, primary)
residual_size = restriction_provider.restriction_size(element,
residual)
- return (
- ((self.current_windowed_value.with_value((
- (element, primary), primary_size)), None), None),
- ((self.current_windowed_value.with_value((
- (element, residual), residual_size)), current_watermark),
None))
+ if self.threadsafe_watermark_estimator:
+ current_watermark = (
Review comment:
Right that's the issue. Here are 2 options:
- Get watermark before splitting like what we did before. The worse case is
we always get earlier watermark then the realistic one.
- Create a synchronized_lock inside the DoFnInvoker, and pass this lock into
`ThreadsafeRestrictionTracker` and `ThreadsafeWatermarkEstimator`.
Take`ThreadsafeWatermarkEstimator` as an example:For the updating method, we
have 2-level locking:
```python
try_claim():
with self.synchronized_lock:
with self._lock:
implementation
try_split():
with self._lock:
implementation
```
In `DoFnInvoker.try_split`:
````python
with self.synchronized_lock:
self.threadsafe_restriction_tacker.try_split()
self.threadsafe_watermark_estimator.current_watermark()
```
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Issue Time Tracking
-------------------
Worklog Id: (was: 370084)
Time Spent: 3h (was: 2h 50m)
> Provide WatermarkEstimatorProvider for different types of WatermarkEstimator
> ----------------------------------------------------------------------------
>
> Key: BEAM-8537
> URL: https://issues.apache.org/jira/browse/BEAM-8537
> Project: Beam
> Issue Type: Improvement
> Components: sdk-py-core, sdk-py-harness
> Reporter: Boyuan Zhang
> Assignee: Boyuan Zhang
> Priority: Major
> Time Spent: 3h
> Remaining Estimate: 0h
>
> This is a follow up for in-progress PR:
> https://github.com/apache/beam/pull/9794.
> Current implementation in PR9794 provides a default implementation of
> WatermarkEstimator. For further work, we want to let WatermarkEstimator to be
> a pure Interface. We'll provide a WatermarkEstimatorProvider to be able to
> create a custom WatermarkEstimator per windowed value. It should be similar
> to how we track restriction for SDF:
> WatermarkEstimator <---> RestrictionTracker
> WatermarkEstimatorProvider <---> RestrictionTrackerProvider
> WatermarkEstimatorParam <---> RestrictionDoFnParam
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