datetime - Pig - 无法将 org.apache.pig.piggybank.evaluation.datetime.convert.ISOToUnix 的匹配函数推断为多个或都不适合

Question

我只是想将 pig 的日期时间格式转换为纪元时间，这样我就可以用时间进行其他计算。下面是我的(部分)脚本:

DEFINE ISOToUnix org.apache.pig.piggybank.evaluation.datetime.convert.ISOToUnix();
A = LOAD 's3://hearstlogfiles/google/NetworkBackfillImpressions_271283/2014/09/24/NetworkBackfillImpressions_271283_20140924_00.gz' USING PigStorage(',');
B = LIMIT A 10;
C = FOREACH B GENERATE
(chararray)(CONCAT(CONCAT(SUBSTRING($0, 0,10),' '),SUBSTRING($0, 11,19) )) as   dt_string:chararray,
DATE_TIME(CONCAT(CONCAT(SUBSTRING($0, 0,10),' '),SUBSTRING($0, 11,19) )) AS dt;
D = FOREACH C GENERATE 
dt_string, 
dt, 
ISOToUnix(dt)/1000 as epoch:long;
DUMP D;

当 pig 尝试执行下面的行时，我在它下面得到了错误。我知道我将 dt 转换为正确的格式。

ISOToUnix(dt)/1000 as epoch:long  
Could not infer the matching function for org.apache.pig.piggybank.evaluation.datetime.convert.ISOToUnix as multiple or none of them fit. Please use an explicit cast.

当我转储 C 时，我得到以下信息。所以我知道 C dt 的格式是正确的。

(2014-09-24 02:53:54,2014-09-24T02:53:54.000Z)  
(2014-09-24 02:57:54,2014-09-24T02:57:54.000Z)  
(2014-09-24 03:05:06,2014-09-24T03:05:06.000Z)  
(2014-09-24 03:27:30,2014-09-24T03:27:30.000Z)  
(2014-09-24 03:37:00,2014-09-24T03:37:00.000Z)  
(2014-09-24 03:39:18,2014-09-24T03:39:18.000Z)  
(2014-09-24 03:41:24,2014-09-24T03:41:24.000Z)  
(2014-09-24 03:43:18,2014-09-24T03:43:18.000Z)  
(2014-09-24 03:58:12,2014-09-24T03:58:12.000Z)  

请帮忙。

Answer 1

粘贴示例来自 https://pig.apache.org/docs/r0.7.0/api/org/apache/pig/piggybank/evaluation/datetime/convert/ISOToUnix.html :

REGISTER /Users/me/commiter/piggybank/java/piggybank.jar ; 
REGISTER /Users/me/commiter/piggybank/java/lib/joda-time-1.6.jar ; 
DEFINE ISOToUnix org.apache.pig.piggybank.evaluation.datetime.convert.ISOToUnix(); 
ISOin = LOAD 'test.tsv' USING PigStorage('\t') AS (dt:chararray, dt2:chararray); 

DESCRIBE ISOin; 
ISOin: {dt: chararray,dt2: chararray} 

DUMP ISOin; 
(2009-01-07T01:07:01.000Z,2008-02-01T00:00:00.000Z) 
(2008-02-06T02:06:02.000Z,2008-02-01T00:00:00.000Z) 
(2007-03-05T03:05:03.000Z,2008-02-01T00:00:00.000Z) 
... 

toUnix = FOREACH ISOin GENERATE ISOToUnix(dt) AS unixTime:long;

DESCRIBE toUnix; 
toUnix: {unixTime: long} 
DUMP toUnix; 
(1231290421000L)
(1202263562000L)
(1173063903000L) 
...

如果您注意到，dt(作为参数传递给 ISOToUnix UDF)是字符数组。因此您需要将“dt”列类型转换为字符数组，如下所示:

C = FOREACH B 
       GENERATE
           (chararray)(CONCAT(CONCAT(SUBSTRING($0, 0,10),' '),
           SUBSTRING($0, 11,19) )) as   dt_string:chararray,
           CONCAT(CONCAT(SUBSTRING($0, 0,10),' '),SUBSTRING($0, 11,19) ) AS dt:chararray;

D = FOREACH C 
       GENERATE 
           dt_string, 
           dt, 
           ISOToUnix((chararray)dt)/1000 as epoch:long;

DUMP D;

希望这对您有所帮助。