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https://issues.apache.org/jira/browse/PIG-953?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12760116#action_12760116
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Ashutosh Chauhan commented on PIG-953:
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Changes look good. Couple of points:
bq. I think this internal structure at this point does not need to be optimized
for lookup
Well, its less about optimization and more about maintainability. First the
relationship between two parallel arrays is implicit. So, if someone is reading
that code he needs to "understand" that relationship of his own. If there is
only one structure relationship would be explicit. Second, there is quite a bit
of code around it, which IMO will be simplified if a single data structure is
instead used. That said, either approach works just as fine so I will leave it
upto you.
bq. Zebra needs column names and cannot work with positions
That is then the limitation of Zebra which it should overcome someone point in
time. There might be a good reason for it, but I fail to see what extra
information names of column provides where type and position of columns should
be sufficient. This also implies an additional requirement on user. If data is
stored using ZebraStorage and if later is loaded back, then user has to provide
the same names for columns that he gave while storing it. No such constraint
exists for any other load-store like PigStorage.
> Enable merge join in pig to work with loaders and store functions which can
> internally index sorted data
> ---------------------------------------------------------------------------------------------------------
>
> Key: PIG-953
> URL: https://issues.apache.org/jira/browse/PIG-953
> Project: Pig
> Issue Type: Improvement
> Affects Versions: 0.3.0
> Reporter: Pradeep Kamath
> Assignee: Pradeep Kamath
> Attachments: PIG-953-2.patch, PIG-953.patch
>
>
> Currently merge join implementation in pig includes construction of an index
> on sorted data and use of that index to seek into the "right input" to
> efficiently perform the join operation. Some loaders (notably the zebra
> loader) internally implement an index on sorted data and can perform this
> seek efficiently using their index. So the use of the index needs to be
> abstracted in such a way that when the loader supports indexing, pig uses it
> (indirectly through the loader) and does not construct an index.
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