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From "Daniel Dai (JIRA)" <j...@apache.org>
Subject [jira] Updated: (PIG-932) Required fields projection in Loader: nested fields in bag/tuple, map key lookup more than two levels
Date Wed, 26 Aug 2009 00:33:59 GMT

     [ https://issues.apache.org/jira/browse/PIG-932?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Daniel Dai updated PIG-932:
---------------------------

    Description: 
To leverage the performance features provided by Zebra, Pig should be able to figure out which
input fields are actually used in Pig script, and prune unnecessary inputs. This feature is
being implementing in [PIG-922|https://issues.apache.org/jira/browse/PIG-922]. However, there
are two limitations currently:

1. Pruning nested fields only apply to map. We do not prune sub-field inside a bag or tuple
2. For map, currently we only go one level deep. Eg, if in Pig script, user uses a#'key0'#'key1',
a#'key0' will be asked

These two limitations are in line with current limitation of Zebra loader. Once Zebra loader
can handle this, we need to work to lift these limitations.

  was:
To leverage the performance features provided by Zebra, Pig should be able to figure out which
input fields are actually used in Pig script, and prune unnecessary inputs. This feature is
being implementing in [PIG-922|https://issues.apache.org/jira/browse/PIG-922]. However, there
are two limitations currently:

1. Pruning nested fields only apply to map and record. We do not prune sub-field inside a
collection
2. For map, currently we only go one level deep. Eg, if in Pig script, user uses a#'key0'#'key1',
a#'key0' will be asked

These two limitations are in line with current limitation of Zebra loader. Once Zebra loader
can handle this, we need to work to lift these limitations.

        Summary: Required fields projection in Loader: nested fields in bag/tuple, map key
lookup more than two levels  (was: Required fields projection in Loader: nested fields in
bag, map key lookup more than two levels)

> Required fields projection in Loader: nested fields in bag/tuple, map key lookup more
than two levels
> -----------------------------------------------------------------------------------------------------
>
>                 Key: PIG-932
>                 URL: https://issues.apache.org/jira/browse/PIG-932
>             Project: Pig
>          Issue Type: Improvement
>          Components: impl
>    Affects Versions: 0.3.0
>            Reporter: Daniel Dai
>
> To leverage the performance features provided by Zebra, Pig should be able to figure
out which input fields are actually used in Pig script, and prune unnecessary inputs. This
feature is being implementing in [PIG-922|https://issues.apache.org/jira/browse/PIG-922].
However, there are two limitations currently:
> 1. Pruning nested fields only apply to map. We do not prune sub-field inside a bag or
tuple
> 2. For map, currently we only go one level deep. Eg, if in Pig script, user uses a#'key0'#'key1',
a#'key0' will be asked
> These two limitations are in line with current limitation of Zebra loader. Once Zebra
loader can handle this, we need to work to lift these limitations.

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