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From "Lavelle, Shawn" <>
Subject RE: Simple UDFS and IN Operator
Date Wed, 09 Mar 2016 19:31:40 GMT
Thanks Edward, (and Gopal),

   This fits with what I was seeing.  I have modified GenericIN to accept a list (by having
it look at the listElementObjInspector), but it still fails to be accepted as a partitionkey
expression.  I traced that to IndexPredicateAnalyzer.analyzeExpr where it’s looking for
an ExprNodeColumnDesc and a ExprNodeConstantDesc. The List will return a WritableListObjectInspector
and java’s collections contains an Immutable list which will yield a WritableConstantListObjectInspector,
but the Element Object Inspector does not pick up the members of the list as constant Expr.
  ( I tried unmodifiableList too, even Collections.unmodifiableList(ImmutableList.copyOf(retArray))
but that doesn’t get me a constant object inspector.)

   I’m guessing bad things™ will happen if I open the analyzeExpr to non-constant expressions?

  Any further insights?

   The array_contains() method won’t work with the modified HIVE I’m working on :/  If
I could get the IN operator to work on LISTS returned from UDFs as a join like it does now
– I’d be set, however, since it’s part of ANTLR I can see how that’s not going to
be the right solution.

   Thanks for your help,

~ Shawn M Lavelle

From: Edward Capriolo []
Sent: Tuesday, March 08, 2016 6:10 PM
Subject: Re: Simple UDFS and IN Operator

The IN UDF is a special one in that unlike many others there is support in the ANTLR language
and parsers for it. The rough answer is it can be done but it is not as direct as making other

On Tue, Mar 8, 2016 at 2:32 PM, Lavelle, Shawn <<>>
Hello All,
   I hope that this question isn’t too rudimentary – but I’m relatively new to HIVE.

   In Hive 0.11, I’ve written a UDF that returns a list of Integers. I’d like to use this
in a WHERE clause of a query, something like SELECT * FROM <table> WHERE <col>
 in ( getList() ). (Extra parenthesis needed to pass the parser.)  Is such a thing possible?
 Keying in values for the list parameter works, but they have WritableConstantIntObjectInspectors
whereas what is returned by my list (despite my best efforts) has an element inspector of
WritabeIntObjectInspector. This doesn’t work.

  So, two questions – Should It? (The HIVE I’m working on is heavily modified :/ ) and
how might I accomplish this?  Joins would be ideal, but we haven’t upgraded yet.

  Thank you for your insight,

~ Shawn M Lavelle

Shawn Lavelle
Software Development

4101 Arrowhead Drive
Medina, Minnesota 55340-9457
Phone: 763 551 0559<tel:763%20551%200559>
Fax: 763 551 0750<tel:763%20551%200750>

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