2017-06-27 60 views
3

我有一個看似簡單的場景,我正在使用python數據流來查詢使用big-query的數據。通過python中的bigquery閱讀器讀取行時AssertError谷歌雲數據流

當bq查詢返回零行時,我遇到一個AssertionError,腳本&聲明錯誤如下所示。我想知道如果這是一個錯誤,或者可能有一個推薦的方式來處理py數據流中的bq閱讀器零行?

數據流腳本:

from apache_beam.io import WriteToText 
from apache_beam.typehints import Any, Dict 

pipeline_options = PipelineOptions(pipeline_args) 
pipeline_options.view_as(SetupOptions).save_main_session = True 
p = beam.Pipeline(options=pipeline_options) 
BIGQUERY_ROW_TYPE = Dict[str, Any] 

# construct a bigquery SQL 
query_sql = Query().build_sql() 
lines = p \ 
     | 'read from bigquery' >> beam.io.Read(beam.io.BigQuerySource(query=query_sql, validate=True)).with_output_types(BIGQUERY_ROW_TYPE) \ 
     | 'write to test' >> WriteToText(known_args.output) 

result = p.run() 

,我看到當查詢返回零行錯誤:

(98b5a6e4c0cd002e): Traceback (most recent call last): 
File "/usr/local/lib/python2.7/dist-packages/dataflow_worker/batchworker.py", line 581, in do_work 
work_executor.execute() 
File "/usr/local/lib/python2.7/dist-packages/dataflow_worker/executor.py", line 166, in execute 
op.start() 
File "/usr/local/lib/python2.7/dist-packages/dataflow_worker/native_operations.py", line 48, in start 
for value in reader: 
File "/usr/local/lib/python2.7/dist-packages/dataflow_worker/nativefileio.py", line 186, in __iter__ 
for eof, record, delta_offset in self.read_records(): 
File "/usr/local/lib/python2.7/dist-packages/dataflow_worker/nativeavroio.py", line 102, in read_records 
assert block.num_records() > 0 
AssertionError 

`2017-06-27 (13:55:58) Workflow failed. Causes: (7390b72dc5ceedb6): S04:read from bigquery+write to test/Write/WriteImpl/Wr... 
(bb74ab934e658b06): Workflow failed. Causes: (7390b72dc5ceedb6): S04:read 
    from bigquery+write to test/Write/WriteImpl/WriteBundles/Do+write to 
    test/Write/WriteImpl/Pair+write to 
    test/Write/WriteImpl/WindowInto(WindowIntoFn)+write to 
    test/Write/WriteImpl/GroupByKey/Reify+write to 
    test/Write/WriteImpl/GroupByKey/Write failed.` 
+0

你有一個實際的查詢嗎? – Pablo

+0

我相信這是Python Dataflow worker中的一個bug。 Avro規範不要求塊具有非零元素計數,但工作人員不正確地強制執行此要求。我們正在修復。 – jkff

+0

@jkff關於這個的任何消息? – Goranek

回答

1

這是一個錯誤,並已修復(按@jkff)。該修補程序將在下一個Dataflow版本中提供 - 應該在3-5周左右。

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