[AIRFLOW-3059] PostgresToGCS Log the number of rows read #3898
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| @@ -134,6 +134,7 @@ def _write_local_data_files(self, cursor): | |||
| """ | |||
| schema = list(map(lambda schema_tuple: schema_tuple[0], cursor.description)) | |||
| file_no = 0 | |||
| row_no = 1 | |||
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maybe a dump question, but why we initialize the variable as 1 not 0? I am not very familiiar with this operator but if the cursor doesn't return any row, the log will still print Received 1 rows?
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Typo I guess, this should be 0 indeed, thanks!
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| @@ -155,6 +156,9 @@ def _write_local_data_files(self, cursor): | |||
| file_no += 1 | |||
| tmp_file_handle = NamedTemporaryFile(delete=True) | |||
| tmp_file_handles[self.filename.format(file_no)] = tmp_file_handle | |||
| row_no += 1 | |||
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| self.log.info('Received %s rows over %s files', row_no, file_no + 1) | |||
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Shouldn't it be just file_no and not file_no + 1?
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Line156 already increments the file_no variable.
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The file_no indicates how many files are being written, to avoid that files grow too big. The row_no should indicate how many lines are being written. So I understand the confusion. The thing is, if no files are being rolled, file_no will still be 0. But if no rows are being written it will say, written 0 rows over 1 file. Let me make this more clear.
To know how many data is being read from Postgres, it is nice to log this to the Airflow log
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@kaxil I've refactored the code a bit, let me know what you think. This changes the behaviour though, the main question is, do we want to create a file if there is nothing to write? |
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I agree with this logic. Can we add tests to check that the file is not created when there are no rows. |
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git diff upstream/master -u -- "*.py" | flake8 --diff