Jarno Seppanen created ARROW-1357:
-------------------------------------

             Summary: Data corruption in reading multi-file parquet dataset
                 Key: ARROW-1357
                 URL: https://issues.apache.org/jira/browse/ARROW-1357
             Project: Apache Arrow
          Issue Type: Bug
          Components: Python
    Affects Versions: 0.5.0
         Environment: python 3.5.3
            Reporter: Jarno Seppanen


I generated a parquet dataset in Spark that has two files. PyArrow corrupts the 
data of the second file if I read them both in using pyarrow's parquet 
directory loading mode.

$ ls -l data
total 28608
-rw-rw-r-- 1 jarno jarno 14651449 Aug 15 09:30 
part-00000-fd2ff92f-201b-4ffc-b0b4-275e06a7fa02.snappy.parquet
-rw-rw-r-- 1 jarno jarno 14636502 Aug 15 09:30 
part-00001-fd2ff92f-201b-4ffc-b0b4-275e06a7fa02.snappy.parquet

import pyarrow.parquet as pq

tab1 = pq.read_table('data')
df1 = tab1.to_pandas()
df1[df1.account_id == 38658373328].legal_labels.tolist()
# [array([ 2,  3,  5,  8, 10, 11, 13, 14, 17, 18, 19, 21, 22, 31, 60, 61, 63,
#        64, 65, 66, 69, 70, 74, 75, 77, 82,  0,  1,  2,  3,  5,  8, 10, 11,
#        13, 14, 17, 18, 19, 21, 22])]


tab2 = 
pq.read_table('data/part-00001-fd2ff92f-201b-4ffc-b0b4-275e06a7fa02.snappy.parquet')
df2 = tab2.to_pandas()
df2[df2.account_id == 38658373328].legal_labels.tolist()
# [array([ 0,  1,  2,  3,  5,  8, 10, 11, 13, 14, 17, 18, 19, 21, 22, 24, 28,
#        30, 31, 36, 38, 39, 40, 41, 43, 49, 60, 61, 62, 63, 64, 65, 66, 67,
#        69, 70, 74, 75, 77, 82, 90])]

Unfortunately I cannot share the data files, and I was not able to create a 
dummy data file pair that would have triggered the bug. I'm sending this bug 
report in the hope that it is still useful without a minimal repro example.



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