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Hive, mail # user - Variable Substitution


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Re: Variable Substitution
Dean Wampler 2013-03-06, 21:30
Even newer versions of Hive do this. Any reason you don't want to provide a
definition for all of them? You could argue that an undefined variable is a
bug and leaving the literal text in place makes it easier to notice.
Although, Unix shells would insert an empty string, so never mind ;)

On Wed, Mar 6, 2013 at 3:13 PM, Matt Tucker <[EMAIL PROTECTED]> wrote:

> Using CDH3u3 (Hive 0.7.1), it appears that variable substitution becomes
> disabled when I use a variable in a query that hasn't been defined.
>
> For instance, using the following script:
>
> set var2=2013-02-01;
> set var3=2013-02-10;
>
> SELECT clndr_dt FROM calendar WHERE clndr_dt LIKE "${hiveconf:var1}" OR
> (clndr_dt >= "${hiveconf:var2}" AND clndr_dt <= "${hiveconf:var3}") LIMIT 1;
>
>
> I would expect the results job configuration to list the hive.query.string
> as:
>
> SELECT clndr_dt FROM calendar WHERE clndr_dt LIKE "${hiveconf:var1}" OR
> (clndr_dt >= "2013-02-01" AND clndr_dt <= "2013-02-10") LIMIT 1;
>
>
> (or with ${hiveconf:var1} removed, leaving an empty string).
>
> Instead, it prints the query as-is (with the variable placeholders).  If I
> set var1=2012-01-01, it properly substitutes the variables, but it only
> returns the '2012-01-01' record (not the 2013 records).
>
> SELECT clndr_dt FROM calendar WHERE clndr_dt LIKE "2012-01-01" OR (
> clndr_dt >= "2013-02-01" AND clndr_dt <= "2013-02-10" ) LIMIT 1
>
> I was originally planning to use this for partition pruning, but it
> doesn't appear to be the cause as the calendar table is not partitioned.
>
> Is there something that I've overlooked?
>
> Thanks!
>
>
--
*Dean Wampler, Ph.D.*
thinkbiganalytics.com
+1-312-339-1330