[jira] [Created] (PIG-3627) Json storage : Doesn't work in cases , where other Store Functions (like PigStorage / AvroStorage) do work.

[jay vyas (JIRA)]

jay vyas created PIG-3627:
-----------------------------

             Summary: Json storage : Doesn't work in cases , where other Store 
Functions (like PigStorage / AvroStorage) do work. 
                 Key: PIG-3627
                 URL: https://issues.apache.org/jira/browse/PIG-3627
             Project: Pig
          Issue Type: Bug
            Reporter: jay vyas


The following query 
{code:title=Bar.java|borderStyle=solid}
        pigServer.registerQuery(
                "uniqcnt  = foreach transactionsG {"+
                               "sym = transactions.product ;"+
                               "dsym = distinct sym  ;"+
                               "generate flatten(dsym.product) as product, 
COUNT(dsym) as count ;" +
                               "};");
{code} 

Results in the schema:

{code} 
   Schema : {product: NULL,count: long}
{code}

This schema, is storable using AvroStorage or PigStorage, but it fails if 
stored using JsonStorage: 

{code}
Failed to parse: <line 1, column 8>  Syntax error, unexpected symbol at or near 
','
        at 
org.apache.pig.parser.QueryParserDriver.parseSchema(QueryParserDriver.java:94)
        at 
org.apache.pig.parser.QueryParserDriver.parseSchema(QueryParserDriver.java:108)
        at org.apache.pig.impl.util.Utils.parseSchema(Utils.java:208)
        at org.apache.pig.impl.util.Utils.getSchemaFromString(Utils.java:182)
        at 
org.apache.pig.builtin.JsonStorage.prepareToWrite(JsonStorage.java:140)
        at 
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat$PigRecordWriter.<init>(PigOutputFormat.java:125)
        at 
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat.getRecordWriter(PigOutputFormat.java:86)
        at 
org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:553)
        at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:408)
        at 
org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:216)

{code}

It appears that JsonStorage is thus less robust than the other storage formats. 
 Can we confirm or deny if some types of data structures do/ do not work with 
JsonStorage? 

So,I suggest:

1) Ideally, I would think JsonStorage should support the same data that other 
Storage functions support.   

the next best thing: 

2) Maybe a wiki page of examples that can / cannot work with JsonStorage and/or 
a better error message would be sufficient to solve this "bug".



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