[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2019-04-11 Thread Victor Tso (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16815763#comment-16815763
 ] 

Victor Tso commented on SPARK-20144:


This one was clearly decided against. I ended up writing my own file source 
strategy, but because we support multiple deployments I had to write a separate 
one for 2.2, 2.3 and 2.4.

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2019-04-11 Thread David Greenberg (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16815755#comment-16815755
 ] 

David Greenberg commented on SPARK-20144:
-

Hello, this issue is also a major one for me. Almost all of the data I work 
with is has a natural sort order, and I store it in CSV, parquet, and orc. 
Unfortunately, some of my datasets are very large, and so I waste a lot of 
compute time loading those datasets out of storage due to Spark throwing out 
serialization information at load & store time.

 

I would really like to see a solution to this problem, as it's fairly expensive 
to our bottom line when using spark.

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-11-23 Thread Dongjoon Hyun (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16697410#comment-16697410
 ] 

Dongjoon Hyun commented on SPARK-20144:
---

Sorry, [~darabos]. IMHO, the proposed way is not consistent with the existing 
Apache Spark design choice. Also, it's not robust enough to be a part of Apache 
Spark because it misleads the user without the guarantee on sort-ness always. 
Lastly, it causes performance degradation because it may try open many small 
files first. I think you had better add your patch into your Spark build if you 
have.

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-11-23 Thread Daniel Darabos (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16697319#comment-16697319
 ] 

Daniel Darabos commented on SPARK-20144:


So where do we go from here? Should I try to find a reviewer?

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-10-15 Thread Daniel Darabos (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16650817#comment-16650817
 ] 

Daniel Darabos commented on SPARK-20144:


Thanks, those are good questions.

# The global option is not great, but it's the simplest. The code is already 
controlled by two global options. ({{spark.sql.files.maxPartitionBytes}} and 
{{spark.sql.files.openCostInBytes}}.) Why not one more?
 # I'm not sure what {{LOAD DATA INPATH}} does. (Sorry...) But sure, users can 
put random-name files in the directory and mess stuff up. Best protection 
against that is not putting random-name files in the directory. :D
 # The whole problem is not Parquet-specific. It affects all file types. The 
{{part-1}} naming comes from Hadoop's 
[FileOutputFormat|https://github.com/apache/hadoop/blob/release-2.7.1/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/output/FileOutputFormat.java#L270].
 It's been like this forever and will never change. (I'd say it's more than a 
convention.)

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-10-15 Thread Dongjoon Hyun (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16650779#comment-16650779
 ] 

Dongjoon Hyun commented on SPARK-20144:
---

[~silvermast] and [~darabos]. 

1. The proposed `spark.sql.files.allowReordering` is a global option for all 
data sources.
2. In parquet tables, can we prevent some users execute 'LOAD DATA INPATH' to 
that folder with a random-name file?
3. Is there any way for Hive/Spark/Parquet to keep that naming convention in 
that table always?

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-10-15 Thread Daniel Darabos (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16650722#comment-16650722
 ] 

Daniel Darabos commented on SPARK-20144:


Yeah, I'm not too happy about the alphabetical ordering either. I thought I 
could simply not sort, and get the "original" order. But at the point where I 
made my change, the files are already in a jumbled order. Maybe it's the file 
system listing order, which could be anything.

99% of the time I'm just reading back a single partitioned Parquet file. In 
this case the alphabetical ordering is the right ordering. ({{part-1}}, 
{{part-2}}, ...) The rows of the resulting DataFrame will be in the same 
order as originally. So I think this issue is satisfied by the change. (The 
test also demonstrates this.)

The 1% case (for me) is when I'm reading back multiple Parquet files with a 
glob in a single {{spark.read.parquet("dir-\{0,5,10}")}} call. In this case it 
would be nice to respect the order given by the user ({{dir-0}}, {{dir-5}}, 
{{dir-10}}). My PR messes this up. ({{dir-0}}, {{dir-10}}, {{dir-5}}) But at 
least the partitions within each Parquet file will be contiguous. That's still 
an improvement.

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-10-15 Thread Victor Tso (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16650704#comment-16650704
 ] 

Victor Tso commented on SPARK-20144:


It should, because by convention the parquet files are 0-padded numerically 
ordered.

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-10-15 Thread Dongjoon Hyun (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16650642#comment-16650642
 ] 

Dongjoon Hyun commented on SPARK-20144:
---

For me, I don't think that PR resolve this issue, `spark.read.parquet no long 
maintains ordering of the data`.

This issue asked 'data ordering'. The alphabetical file path order doesn't 
guarantee the order of the data, does it?

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-10-15 Thread Daniel Darabos (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16650492#comment-16650492
 ] 

Daniel Darabos commented on SPARK-20144:


Thanks Victor! I've expanded the test with a case where reordering is allowed, 
and I've added some explanatory comments in the test.

[~dongjoon], what do you think? Should I try to foster more discussion? Or what 
could be a next step?

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-10-15 Thread Victor Tso (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16650303#comment-16650303
 ] 

Victor Tso commented on SPARK-20144:


I looked at the PR and liked what I saw. I would only suggest the test be 
duplicated for true and/or the PR comment be added to the test code itself.

We have a customer where the records do not have a declared ordering of values 
but the records' appearance order is significant. Turning on our feature flag 
to use Spark's parquet reader violates their expectation of ordering so we are 
unable to shepherd them to this feature flag. Any help along the lines of this 
Jira and PR would be appreciated.

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-10-08 Thread Daniel Darabos (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16642401#comment-16642401
 ] 

Daniel Darabos commented on SPARK-20144:


Sorry, I had an idea for a quick fix for this and sent a pull request without 
discussing it first. Let me copy the rationale from the PR:

I'm adding {{spark.sql.files.allowReordering}}, defaulting to {{true}}. When 
set to {{true}} the behavior is as before. When set to {{false}}, the input 
files are read in alphabetical order. This means partitions are read in the 
{{part-1}}, {{part-2}}, {{part-3}}... order, recovering the same 
ordering as before.

While *SPARK-20144* has been closed as "Not A Problem", I think this is still a 
valuable feature. Spark has been 
[touted|https://databricks.com/blog/2016/11/14/setting-new-world-record-apache-spark.html]
 as the best tool for sorting. It certainly can sort data. But without this 
change, it can not read back sorted data on the DataFrame API.

My practical use case is that we allow users to run their SQL expressions 
through our UI. We also allow them to ask for the results to be persisted to 
Parquet files. We noticed that if they do an {{ORDER BY}}, the ordering is lost 
if they also ask for persistence. For example they might want to rank data 
points by a score, so they can later get the top 10 or top 10,000,000 entries 
easily. With this change we could fulfill this use case.

The fix is small and safe. (25 lines including test and docs, only changes 
behavior when new flag is set.) Is there a reason not to do this?

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-10-08 Thread Apache Spark (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16642038#comment-16642038
 ] 

Apache Spark commented on SPARK-20144:
--

User 'darabos' has created a pull request for this issue:
https://github.com/apache/spark/pull/22673

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-10-08 Thread Apache Spark (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16642036#comment-16642036
 ] 

Apache Spark commented on SPARK-20144:
--

User 'darabos' has created a pull request for this issue:
https://github.com/apache/spark/pull/22673

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-05-30 Thread sam (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16494852#comment-16494852
 ] 

sam commented on SPARK-20144:
-

Regarding the original issue of sorting, I agree with [~srowen] in that it 
should be up to the user to explicitly ask for sorted data. This is because 
fundamentally Spark implements the Map Reduce programming paradigm which is 
defined in terms of multisets. [~icexelloss] Please read  
[http://theory.stanford.edu/~sergei/papers/soda10-mrc.pdf]

Regarding my issue of Spark reducing the number of partitions without any ask 
from the user I've created a separate issue: 
https://issues.apache.org/jira/browse/SPARK-24425

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2018-05-30 Thread Unai Sarasola (JIRA)


[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16494810#comment-16494810
 ] 

Unai Sarasola commented on SPARK-20144:
---

But if you want to have exactly a copy from your data in HDFS for example, this 
would made impossible to Spark to maintain the copy of the files exactly in 
both cases.

Is that right

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>Priority: Major
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2017-10-13 Thread sam (JIRA)

[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16203882#comment-16203882
 ] 

sam commented on SPARK-20144:
-

I think this is a regression.  We used to be able to easily control the number 
of output files / tasks based on num files and coalesce.  Now I have to use 
`repartition` to get the desired num files / partitions which is unnecessarily 
expensive.

I've tried playing with spark.sql.files.maxPartitionBytes and 
spark.sql.files.openCostInBytes to see if I can force the conventional 
behaviour.

{code}
val ss = SparkSession.builder().appName("uber-cp").master(conf.master())
 .config("spark.sql.files.maxPartitionBytes", 1)
 .config("spark.sql.files.openCostInBytes", Long.MaxValue)
{code}

This didn't work.  Spark just squashes all my parquet files into less 
partitions.

Suggest a simple `option` on DataFrameReader that can disable this (or enable 
it, default behaviour should be same as 1.6).

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2017-05-04 Thread Bill (JIRA)

[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15996517#comment-15996517
 ] 

Bill commented on SPARK-20144:
--

Increasing {{spark.sql.files.openCostInBytes}} prevents the individual parquet 
files from being combined, but it does not prevent them from being reordered: 
[DataSourceScanExec - spark 
2.1.0|https://github.com/apache/spark/blob/v2.1.0/sql/core/src/main/scala/org/apache/spark/sql/execution/DataSourceScanExec.scala#L499]

It seems somewhat inconsistent to respect the within-file ordering of a 
file-based source (parquet in this case), but not the between-file ordering, 
even though the order of files can also convey information.

Does it make sense to include an option that tells spark to also respect the 
file order for a file-based source when constructing the partition list? 
Multiple small files could still be combined into the same partition for 
efficiency, but this would allow the user to tell spark that the order of files 
matters and should be kept (within and between partitions). 

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2017-04-07 Thread Andrew Ash (JIRA)

[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15961170#comment-15961170
 ] 

Andrew Ash commented on SPARK-20144:


This is a regression from 1.6 to the 2.x line.  [~marmbrus] recommended 
modifying {{spark.sql.files.openCostInBytes}} as a workaround in this post:

http://apache-spark-developers-list.1001551.n3.nabble.com/Sorting-within-partitions-is-not-maintained-in-parquet-td18618.html#a18627

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2017-04-04 Thread Li Jin (JIRA)

[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15956030#comment-15956030
 ] 

Li Jin commented on SPARK-20144:


> When you save the sorted data into Parquet, only the data in individual 
> Parquet file can maintain the data ordering
This is something changed in Spark 2 as well? write.parquet doesn't write 
parquet files in the order of partitions any more?

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2017-04-03 Thread Liang-Chi Hsieh (JIRA)

[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15954559#comment-15954559
 ] 

Liang-Chi Hsieh commented on SPARK-20144:
-

I don't think the API has the guarantee about the data ordering. The difference 
between 1.6.3 to 2.0.2 is just due to the change of internal implementation.

I checked the current FileSourceScanExec, it still reorders the partition files.

When you save the sorted data into Parquet, only the data in individual Parquet 
file can maintain the data ordering. We shouldn't expect a special ordering on 
the whole data read back, if the API doesn't explicitly guarantee that.

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2017-03-31 Thread Li Jin (JIRA)

[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15951202#comment-15951202
 ] 

Li Jin commented on SPARK-20144:


Thanks Sean! I appreciate your time and help very much.

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2017-03-31 Thread Sean Owen (JIRA)

[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15951095#comment-15951095
 ] 

Sean Owen commented on SPARK-20144:
---

Probably best to wait for an informed opinion but I would assume for now you 
need to sort. 

I'm just saying that theoretically sorted data needs no data movement to become 
sorted because it is already. It may not actually even be expensive

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2017-03-31 Thread Li Jin (JIRA)

[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15951084#comment-15951084
 ] 

Li Jin commented on SPARK-20144:


Also, I am not sure about "If the data were sorted, sorting would be pretty 
cheap". Can you explain more on this?

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2017-03-31 Thread Li Jin (JIRA)

[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15951073#comment-15951073
 ] 

Li Jin commented on SPARK-20144:


I totally agree Correctness takes precedence. If sorting is the only way, we 
will do that, but I think there is way we can maintain ordering in parquet 
format.

Parquet itself doesn't change the ordering, data in parquet is stored with 
parquet_file_0, parquet_file_1 ... and data are ordered within those files. 
However, it is FileSourceStrategy 
(https://github.com/apache/spark/blob/v2.0.2/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/FileSourceStrategy.scala#L168)
 that resorts parquet files and end up changing the ordering.

If the expected semantics of Parquet doesn't maintain order, I won't complain 
the behavior of spark.read.parquet, but it seems it's Catalyst that is changing 
the ordering here.

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2017-03-31 Thread Sean Owen (JIRA)

[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15950988#comment-15950988
 ] 

Sean Owen commented on SPARK-20144:
---

If the data were sorted, sorting would be pretty cheap, in general. Correctness 
has to take precedence in any event, if you're describing this as a blocker for 
you.
I don't believe projection can change ordering, no. I am saying that I would 
not necessarily expect that to extend to external serialization. I don't see 
that being tabular or on HDFS matters. I think some serializations would 
naturally preserve order and others would not. I am still not 100% sure what 
the expected semantics of Parquet are here, but you have de facto evidence it 
is not guaranteed.

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2017-03-31 Thread Li Jin (JIRA)

[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15950979#comment-15950979
 ] 

Li Jin commented on SPARK-20144:


Thanks for getting back to me.

Sorting in this case will just add extra cost to in our workflow and we are 
trying to avoid it in the first place.

Because DataFrame presents the data in a tabular format, it is very surprising 
that the table changes after going through hdfs. In any other tabular format 
that I know of, ordering of rows is a property of the data and it is surprising 
that reading/writing changes properties of the data. This is also a bit scary 
because if ordering were not a property of a DataFrame, can things like cache 
or select("col") change ordering of rows in the future? 


> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2017-03-31 Thread Sean Owen (JIRA)

[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15950627#comment-15950627
 ] 

Sean Owen commented on SPARK-20144:
---

If you need a particular ordering, I think you need to sort. I am not sure 
ordering is particularly guaranteed in the format or the reading of it.

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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[jira] [Commented] (SPARK-20144) spark.read.parquet no long maintains ordering of the data

2017-03-30 Thread Li Jin (JIRA)

[ 
https://issues.apache.org/jira/browse/SPARK-20144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15950221#comment-15950221
 ] 

Li Jin commented on SPARK-20144:


Ping, anyone? This is a pretty big blocker for us.

> spark.read.parquet no long maintains ordering of the data
> -
>
> Key: SPARK-20144
> URL: https://issues.apache.org/jira/browse/SPARK-20144
> Project: Spark
>  Issue Type: Bug
>  Components: SQL
>Affects Versions: 2.0.2
>Reporter: Li Jin
>
> Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is 
> when we read parquet files in 2.0.2, the ordering of rows in the resulting 
> dataframe is not the same as the ordering of rows in the dataframe that the 
> parquet file was reproduced with. 
> This is because FileSourceStrategy.scala combines the parquet files into 
> fewer partitions and also reordered them. This breaks our workflows because 
> they assume the ordering of the data. 
> Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec 
> changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 
> 2.1.



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