10

I wanted to understand the UDF WeekOfYear and how it starts the first week. I had to artifically hit a table and run the query . I wanted to not hit the table and compute the values. Secondly can I look at the UDF source code?

SELECT weekofyear
('12-31-2013')
from a;
leftjoin
  • 36,950
  • 8
  • 57
  • 116
vkaul11
  • 4,098
  • 12
  • 47
  • 79

4 Answers4

6

You do not need table to test UDF since Hive 0.13.0.

See this Jira: HIVE-178 SELECT without FROM should assume a one-row table with no columns

Test:

hive> SELECT weekofyear('2013-12-31');

Result:

1

The source code (master branch) is here: UDFWeekOfYear.java

leftjoin
  • 36,950
  • 8
  • 57
  • 116
1

If you are Java developer, you can write Junit Test cases and test the UDFs..

you can search the source code of all hive built in functions in grepcode.

http://grepcode.com/file/repo1.maven.org/maven2/org.apache.hive/hive-exec/1.0.0/org/apache/hadoop/hive/ql/udf/UDFWeekOfYear.java

gopikrishna_BD
  • 99
  • 3
0

I don't think executing UDF without hitting the tables is possible in Hive. Even Hive developers hit the table in UDF testing.

To make query run faster you can:

  1. Create table with only one row and run UDF queries on this table
  2. Run Hive in local mode.

Hive source code is located here. UDFWeekOfYear source is here.

Nigel Tufnel
  • 11,146
  • 4
  • 35
  • 31
0

You should be able to use any table with at least one row to test functions. Here is an example using a few custom functions that perform work and output a string result.

Replace anytable with an actual table.

SELECT ST_AsText(ST_Intersection(ST_Polygon(2,0, 2,3, 3,0), ST_Polygon(1,1, 4,1, 4,4, 1,4))) FROM anytable LIMIT 1;

HIVE Resuluts:

OK

POLYGON ((2 1, 2.6666666666666665 1, 2 3, 2 1))

Time taken: 0.191 seconds, Fetched: 1 row(s)

hive>

jon kish
  • 1
  • 3