Hi team, I have another question when using Beam Dataframe IO connector. I tried to_parquet, and my data are written to several different files. I am wondering how I can control the number of files (shards) or how the sharding is done for to_parquet and other Beam Dataframe IO APIs?
Thank you! Wenbing On Tue, May 11, 2021 at 12:20 PM Kenneth Knowles <k...@google.com> wrote: > +dev <d...@beam.apache.org> > > In the Beam Java ecosystem, this functionality is provided by the Sorter > library ( > https://beam.apache.org/documentation/sdks/java-extensions/#sorter). I'm > curious what people think about various options: > > - Python version of the transform(s) > - Expose sorter as xlang transform(s) > - Convenience transforms (that use pandas in DoFns?) to just do it for > small data per key to achieve compatibility > - Beam model extension so that runners can do it as part of GBK > > Kenn > > On Mon, May 10, 2021 at 5:26 PM Wenbing Bai <wenbing....@getcruise.com> > wrote: > >> Hi Robert and Brian, >> >> I don't know why I didn't catch your replies. But thank you so much for >> looking at this. >> >> My parquet files will be consumed by downstreaming processes which >> require data points with the same "key1" that are sorted by "key2". The >> downstreaming process, for example, will make a rolling window with size N >> that reads N records together at one time. But note, the rolling window >> will not cross different "key1". >> >> So that is saying, 1) I don't need to sort the whole dataset. 2) all data >> with the same "key1" should be located together. >> >> I am not sure if I explain the use case clearly. Let me know what you >> think. >> >> Wenbing >> >> >> On Tue, Apr 20, 2021 at 5:01 PM Robert Bradshaw <rober...@google.com> >> wrote: >> >>> It would also be helpful to understand what your overall objective is >>> with this output. Is there a reason you need it sorted/partitioned in a >>> certain way? >>> >>> On Tue, Apr 20, 2021 at 4:51 PM Brian Hulette <bhule...@google.com> >>> wrote: >>> >>>> Hi Wenbing, >>>> Sorry for taking so long to get back to you on this. >>>> I discussed this with Robert offline and we came up with a potential >>>> workaround - you could try writing out the Parquet file from within the >>>> groupby.apply method. You can use beam's FileSystems abstraction to open a >>>> Python file object referencing a cloud storage file, and pass that file >>>> object directly to the pandas to_parquet. It would look something like >>>> this: >>>> >>>> df.groupby('key1').apply(lambda df: >>>> df.sort_values(by='key2').to_parquet(FileSystems.open("gs://bucket/file.pq")) >>>> >>>> If writing out sorted, partitioned parquet files is a common use-case >>>> we should think about making this easier though. At the very least >>>> partition_cols should work, I filed BEAM-12201 [1] for this. That alone >>>> won't be enough as our implementation will likely reshuffle the dataset to >>>> enforce the partitioning, removing any sorting that you've applied, so we'd >>>> also need to think about how to optimize the pipeline to avoid that >>>> shuffle. >>>> >>>> Brian >>>> >>>> [1] https://issues.apache.org/jira/browse/BEAM-12201 >>>> >>>> On Wed, Apr 7, 2021 at 9:02 PM Wenbing Bai <wenbing....@getcruise.com> >>>> wrote: >>>> >>>>> Thank you, Brian. I tried `partition_cols`, but it is not working. I >>>>> tried pure pandas, it does work, so I am not sure if anything wrong with >>>>> Beam. >>>>> >>>>> Wenbing >>>>> >>>>> On Wed, Apr 7, 2021 at 2:56 PM Brian Hulette <bhule...@google.com> >>>>> wrote: >>>>> >>>>>> Hm, to_parquet does have a `partition_cols` argument [1] which we >>>>>> pass through [2]. It would be interesting to see what >>>>>> `partition_cols='key1'` does - I suspect it won't work perfectly though. >>>>>> >>>>>> Do you have any thoughts here Robert? >>>>>> >>>>>> [1] >>>>>> https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.to_parquet.html >>>>>> [2] >>>>>> https://github.com/apache/beam/blob/a8cd05932bed9b2480316fb8518409636cb2733b/sdks/python/apache_beam/dataframe/io.py#L525 >>>>>> >>>>>> On Wed, Apr 7, 2021 at 2:22 PM Wenbing Bai <wenbing....@getcruise.com> >>>>>> wrote: >>>>>> >>>>>>> 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 < >>>>>>> wenbing....@getcruise.com> 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 <bhule...@google.com> >>>>>>>> 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 < >>>>>>>>> rober...@google.com> 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 < >>>>>>>>>> wenbing....@getcruise.com> 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. >>>>>> >>>>>> >>>>> >>>>> -- >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> 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 >> >> >> >> *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 -- *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.
