我正在尝试使用 SpannerIO 将 MutationGroups 流式传输到扳手中。
目标是每 10 秒写入新的 MuationGroup，因为我们将使用 Spanner 来查询近期 KPI。
当我不使用任何 Windows 时，出现以下错误：
Exception in thread "main" java.lang.IllegalStateException: GroupByKey cannot be applied to non-bounded PCollection in the GlobalWindow without a trigger. Use a Window.into or Window.triggering transform prior to GroupByKey.
at org.apache.beam.sdk.transforms.GroupByKey.applicableTo(GroupByKey.java:173)
at org.apache.beam.sdk.transforms.GroupByKey.expand(GroupByKey.java:204)
at org.apache.beam.sdk.transforms.GroupByKey.expand(GroupByKey.java:120)
at org.apache.beam.sdk.Pipeline.applyInternal(Pipeline.java:537)
at org.apache.beam.sdk.Pipeline.applyTransform(Pipeline.java:472)
at org.apache.beam.sdk.values.PCollection.apply(PCollection.java:286)
at org.apache.beam.sdk.transforms.Combine$PerKey.expand(Combine.java:1585)
at org.apache.beam.sdk.transforms.Combine$PerKey.expand(Combine.java:1470)
at org.apache.beam.sdk.Pipeline.applyInternal(Pipeline.java:537)
at org.apache.beam.sdk.Pipeline.applyTransform(Pipeline.java:491)
at org.apache.beam.sdk.values.PCollection.apply(PCollection.java:299)
at org.apache.beam.sdk.io.gcp.spanner.SpannerIO$WriteGrouped.expand(SpannerIO.java:868)
at org.apache.beam.sdk.io.gcp.spanner.SpannerIO$WriteGrouped.expand(SpannerIO.java:823)
at org.apache.beam.sdk.Pipeline.applyInternal(Pipeline.java:537)
at org.apache.beam.sdk.Pipeline.applyTransform(Pipeline.java:472)
at org.apache.beam.sdk.values.PCollection.apply(PCollection.java:286)
at quantum.base.transform.entity.spanner.SpannerProtoWrite.expand(SpannerProtoWrite.java:52)
at quantum.base.transform.entity.spanner.SpannerProtoWrite.expand(SpannerProtoWrite.java:20)
at org.apache.beam.sdk.Pipeline.applyInternal(Pipeline.java:537)
at org.apache.beam.sdk.Pipeline.applyTransform(Pipeline.java:491)
at org.apache.beam.sdk.values.PCollection.apply(PCollection.java:299)
at quantum.entitybuilder.pipeline.EntityBuilderPipeline$Write$SpannerWrite.expand(EntityBuilderPipeline.java:388)
at quantum.entitybuilder.pipeline.EntityBuilderPipeline$Write$SpannerWrite.expand(EntityBuilderPipeline.java:372)
at org.apache.beam.sdk.Pipeline.applyInternal(Pipeline.java:537)
at org.apache.beam.sdk.Pipeline.applyTransform(Pipeline.java:491)
at org.apache.beam.sdk.values.PCollection.apply(PCollection.java:299)
at quantum.entitybuilder.pipeline.EntityBuilderPipeline.main(EntityBuilderPipeline.java:122)
:entityBuilder FAILED
由于上述错误，我假设输入集合需要窗口化并触发，因为 SpannerIO 使用 GroupByKey （这也是我的用例所需要的）：
...
.apply("1-minute windows", Window.<MutationGroup>into(FixedWindows.of(Duration.standardMinutes(1)))
.triggering(Repeatedly.forever(AfterProcessingTime
.pastFirstElementInPane()
.plusDelayOf(Duration.standardSeconds(10))
).orFinally(AfterWatermark.pastEndOfWindow()))
.discardingFiredPanes()
.withAllowedLateness(Duration.ZERO))
.apply(SpannerIO.write()
.withProjectId(entityConfig.getSpannerProject())
.withInstanceId(entityConfig.getSpannerInstance())
.withDatabaseId(entityConfig.getSpannerDb())
.grouped());
当我这样做时，我在运行时遇到以下异常：
java.lang.IllegalArgumentException: Attempted to get side input window for GlobalWindow from non-global WindowFn
org.apache.beam.sdk.transforms.windowing.PartitioningWindowFn$1.getSideInputWindow(PartitioningWindowFn.java:49)
com.google.cloud.dataflow.worker.StreamingModeExecutionContext$StepContext.issueSideInputFetch(StreamingModeExecutionContext.java:631)
com.google.cloud.dataflow.worker.StreamingModeExecutionContext$UserStepContext.issueSideInputFetch(StreamingModeExecutionContext.java:683)
com.google.cloud.dataflow.worker.StreamingSideInputFetcher.storeIfBlocked(StreamingSideInputFetcher.java:182)
com.google.cloud.dataflow.worker.StreamingSideInputDoFnRunner.processElement(StreamingSideInputDoFnRunner.java:71)
com.google.cloud.dataflow.worker.SimpleParDoFn.processElement(SimpleParDoFn.java:323)
com.google.cloud.dataflow.worker.util.common.worker.ParDoOperation.process(ParDoOperation.java:43)
com.google.cloud.dataflow.worker.util.common.worker.OutputReceiver.process(OutputReceiver.java:48)
com.google.cloud.dataflow.worker.SimpleParDoFn$1.output(SimpleParDoFn.java:271)
org.apache.beam.runners.core.SimpleDoFnRunner.outputWindowedValue(SimpleDoFnRunner.java:219)
org.apache.beam.runners.core.SimpleDoFnRunner.access$700(SimpleDoFnRunner.java:69)
org.apache.beam.runners.core.SimpleDoFnRunner$DoFnProcessContext.output(SimpleDoFnRunner.java:517)
org.apache.beam.runners.core.SimpleDoFnRunner$DoFnProcessContext.output(SimpleDoFnRunner.java:505)
org.apache.beam.sdk.values.ValueWithRecordId$StripIdsDoFn.processElement(ValueWithRecordId.java:145)
经过进一步调查，似乎是由于.apply(Wait.on(input))在 SpannerIO 中：它有一个全局侧输入，似乎不适用于我的固定窗口，如文档所示Wait.java state:
If signal is globally windowed, main input must also be. This typically would be useful
* only in a batch pipeline, because the global window of an infinite PCollection never
* closes, so the wait signal will never be ready.
作为临时解决方法，我尝试了以下方法：
-
添加带有触发器的全局窗口而不是固定窗口：
.apply("globalwindow", Window.<MutationGroup>into(new GlobalWindows())
.triggering(Repeatedly.forever(AfterProcessingTime
.pastFirstElementInPane()
.plusDelayOf(Duration.standardSeconds(10))
).orFinally(AfterWatermark.pastEndOfWindow()))
.discardingFiredPanes()
.withAllowedLateness(Duration.ZERO))
这会导致仅当我耗尽管道时才写入扳手。我的印象是Wait.on()信号仅在全局窗口关闭时触发，并且不适用于触发器。
-
禁用.apply(Wait.on(input))在 SpannerIO 中：
这会导致管道卡在视图创建上
在此 SO 帖子中进行了描述：SpannerIO Dataflow 2.3.0 卡在 CreateDataflowView 中 https://stackoverflow.com/questions/49273528/spannerio-dataflow-2-3-0-stuck-in-createdataflowview.
当我检查工作日志以获取线索时，我确实收到以下警告：
logger: "org.apache.beam.sdk.coders.SerializableCoder"
message: "Can't verify serialized elements of type SpannerSchema have well defined equals method. This may produce incorrect results on some PipelineRunner
logger: "org.apache.beam.sdk.coders.SerializableCoder"
message: "Can't verify serialized elements of type BoundedSource have well defined equals method. This may produce incorrect results on some PipelineRunner"
请注意，一切都适用于 DirectRunner，并且我正在尝试使用 DataflowRunner。
对于我可以尝试让它运行的事情，有人有任何其他建议吗？我很难想象我是唯一一个尝试将 MutationGroups 流式传输到扳手中的人。
提前致谢！
