Details
Major Description
Hello all, I think I have outlined a bug in the hive split function:
Summary: When calling split on a string of data, it will only return all array items if the the last array item has a value. For example, if I have a string of text delimited by tab with 7 columns, and the first four are filled, but the last three are blank, split will only return a 4 position array. If any number of "middle" columns are empty, but the last item still has a value, then it will return the proper number of columns. This was tested in Hive 0.9 and hive 0.11.
Data:
(Note \t represents a tab char, \x09 the line endings should be \n (UNIX style) not sure what email will do to them). Basically my data is 7 lines of data with the first 7 letters separated by tab. On some lines I've left out certain letters, but kept the number of tabs exactly the same.
input.txt
a\tb\tc\td\te\tf\tg
a\tb\tc\td\te\t\tg
a\tb\t\td\t\tf\tg
\t\t\td\te\tf\tg
a\tb\tc\td\t\t\t
a\t\t\t\te\tf\tg
a\t\t\td\t\t\tg
I then created a table with one column from that data:
DROP TABLE tmp_jo_tab_test;
CREATE table tmp_jo_tab_test (message_line STRING)
STORED AS TEXTFILE;
LOAD DATA LOCAL INPATH '/tmp/input.txt'
OVERWRITE INTO TABLE tmp_jo_tab_test;
Ok just to validate I created a python counting script:
#!/usr/bin/python
import sys
for line in sys.stdin:
line = line[0:-1]
out = line.split("\t")
print len(out)
The output there is :
$ cat input.txt |./cnt_tabs.py
7
7
7
7
7
7
7
Based on that information, split on tab should return me 7 for each line as well:
hive -e "select size(split(message_line, '
t')) from tmp_jo_tab_test;"
7
7
7
7
4
7
7
However it does not. It would appear that the line where only the first four letters are filled in(and blank is passed in on the last three) only returns 4 splits, where there should technically be 7, 4 for letters included, and three blanks.
a\tb\tc\td\t\t\t