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From "Santhosh Srinivasan (JIRA)" <j...@apache.org>
Subject [jira] Commented: (PIG-796) support conversion from numeric types to chararray
Date Tue, 12 May 2009 01:08:45 GMT

    [ https://issues.apache.org/jira/browse/PIG-796?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12708281#action_12708281
] 

Santhosh Srinivasan commented on PIG-796:
-----------------------------------------

Pig supports conversion of numeric types to chararray. The issue being talked about in this
jira is about conversion of types that come out of maps. Currently, Pig assumes that bytearray
is the type of the value. However, when users use non-bytearray types, (like Double, Integer,
etc.), then conversions fail. Pig is expecting a bytearray and finds a different type, resulting
in ClassCastException.

An example to illustrate the point. In the script below, the user is explicitly casting the
value to a chararray. If the map returns an Integer or a Double, then Pig will bail out with
a ClassCastException.

{code}
foreach input generate (chararray)mymap#'key' as myvalue;
{code}

A proposal to address this issue.

Instead of bailing out, Pig should examine the type of the value. Depending on the expected
type (implicit/explicit casts), perform a conversion. These changes are localized to the POCast.java
The implication of this change is a possible slower performance that can be minimized by caching
the value type.

On a side note, this issue plays a role in the larger issue of handling unknown types. That
is a much bigger topic.

> support  conversion from numeric types to chararray
> ---------------------------------------------------
>
>                 Key: PIG-796
>                 URL: https://issues.apache.org/jira/browse/PIG-796
>             Project: Pig
>          Issue Type: Improvement
>    Affects Versions: 0.2.0
>            Reporter: Olga Natkovich
>


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