Hi Robert and Brian,
I tried groupby in my case. Here is my pipeline code. I do see all the data
in the final parquet file are sorted in each group. However, I'd like to
write each partition (group) to an individual file, how can I achieve it?
In addition, I am using the master of Apache Beam SDK, how can I test the
pipeline with DataflowRunner considering there is no dataflow worker image
available?
data = [
{
"key1": 1000 + i % 10,
"key2": randrange(10000),
"feature_1": "somestring{}".format(i)
} for i in range(10000)
]
class TestRow(typing.NamedTuple):
key1: int
key2: int
feature_1: str
with beam.Pipeline() as p:
pcoll = (
p
| beam.Create(data)
| beam.Map(lambda x:x).with_output_types(TestRow)
)
df = to_dataframe(pcoll)
sorted_df = df.groupby('key1').apply(lambda df: df.sort_values(by='key2')
sorted_df.to_parquet('test_beam_dataframe{}.parquet'.format(str
(uuid.uuid4())[:8]), engine='pyarrow', index=False)
On Fri, Apr 2, 2021 at 10:00 AM Wenbing Bai <[email protected]>
wrote:
> Thank you, Robert and Brian.
>
> I'd like to try this out. I am trying to distribute my dataset to nodes,
> sort each partition by some key and then store each partition to its own
> file.
>
> Wenbing
>
> On Fri, Apr 2, 2021 at 9:23 AM Brian Hulette <[email protected]> wrote:
>
>> Note groupby.apply [1] in particular should be able to do what you want,
>> something like:
>>
>> df.groupby('key1').apply(lambda df: df.sort_values('key2'))
>>
>> But as Robert noted we don't make any guarantees about preserving this
>> ordering later in the pipeline. For this reason I actually just sent a PR
>> to disallow sort_values on the entire dataset [2].
>>
>> Brian
>>
>> [1] https://github.com/apache/beam/pull/13843
>> [2] https://github.com/apache/beam/pull/14324
>>
>> On Fri, Apr 2, 2021 at 9:15 AM Robert Bradshaw <[email protected]>
>> wrote:
>>
>>> Thanks for trying this out.
>>>
>>> Better support for groupby (e.g.
>>> https://github.com/apache/beam/pull/13843 ,
>>> https://github.com/apache/beam/pull/13637) will be available in the
>>> next Beam release (2.29, in progress, but you could try out head if you
>>> want). Note, however, that Beam PCollections are by definition unordered,
>>> so unless you sort a partition and immediately do something with it that
>>> ordering may not be preserved. If you could let us know what you're trying
>>> to do with this ordering that would be helpful.
>>>
>>> - Robert
>>>
>>>
>>> On Thu, Apr 1, 2021 at 7:31 PM Wenbing Bai <[email protected]>
>>> wrote:
>>>
>>>> Hi Beam users,
>>>>
>>>> I have a user case to partition my PCollection by some key, and then
>>>> sort my rows within the same partition by some other key.
>>>>
>>>> I feel Beam Dataframe could be a candidate solution, but I cannot
>>>> figure out how to make it work. Specifically, I tried df.groupby where I
>>>> expect my data will be distributed to different nodes. I also tried
>>>> df.sort_values, but it will sort my whole dataset, which is not what I
>>>> need.
>>>>
>>>> Can someone shed some light on this?
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Wenbing Bai
>>>>
>>>> Senior Software Engineer
>>>>
>>>> Data Infrastructure, Cruise
>>>>
>>>> Pronouns: She/Her
>>>>
>>>>
>>>>
>>>> *Confidentiality Note:* We care about protecting our proprietary
>>>> information, confidential material, and trade secrets. This message
>>>> may contain some or all of those things. Cruise will suffer material harm
>>>> if anyone other than the intended recipient disseminates or takes any
>>>> action based on this message. If you have received this message (including
>>>> any attachments) in error, please delete it immediately and notify the
>>>> sender promptly.
>>>
>>>
>
> --
>
>
>
>
>
> Wenbing Bai
>
> Senior Software Engineer
>
> Data Infrastructure, Cruise
>
> Pronouns: She/Her
>
>
--
Wenbing Bai
Senior Software Engineer
Data Infrastructure, Cruise
Pronouns: She/Her
--
*Confidentiality Note:* We care about protecting our proprietary
information, confidential material, and trade secrets. This message may
contain some or all of those things. Cruise will suffer material harm if
anyone other than the intended recipient disseminates or takes any action
based on this message. If you have received this message (including any
attachments) in error, please delete it immediately and notify the sender
promptly.
