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https://issues.apache.org/jira/browse/HIVE-30136?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Hemanth Umashankar updated HIVE-30136:
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Component/s: Vectorization
> Fix vectorized LEAD/LAG literal defaults for DOUBLE/DECIMAL
> -----------------------------------------------------------
>
> Key: HIVE-30136
> URL: https://issues.apache.org/jira/browse/HIVE-30136
> Project: Hive
> Issue Type: Bug
> Components: Vectorization
> Reporter: Hemanth Umashankar
> Assignee: Hemanth Umashankar
> Priority: Major
>
> h3. Summary
> With vectorization enabled, {{LAG}}/{{LEAD}} with a double-literal default
> returns {{0.0}} on rows that should use the default (e.g. the first row per
> partition for {{LAG}} with offset 1). With vectorization disabled, the same
> query returns the correct default.
> Suspected cause: {{VectorPTFEvaluatorAbstractLeadLag.initDefaultValue()}}
> always uses {{ConstantVectorExpression.getLongValue()}}. Double literals are
> stored in {{doubleValue}}, so {{longValue}} is 0.
> h3. Repro
> {code:sql}
> CREATE TABLE lag_default_repro (
> region STRING,
> sale_id INT,
> amount DOUBLE
> );
> INSERT INTO lag_default_repro VALUES
> ('east', 1, 10.0),
> ('east', 2, 20.0),
> ('west', 1, 100.0);
> -- Run the query below twice: once with =false, once with =true
> SET hive.vectorized.execution.enabled=false;
> SELECT
> region, sale_id, amount,
> LAG(amount, 1, 2.5) OVER (PARTITION BY region ORDER BY sale_id) AS
> prev_amount_or_default
> FROM lag_default_repro
> ORDER BY region, sale_id;
> {code}
> h3. Expected vs. actual
> Rows that should use the default (east/1 and west/1) show {{2.5}} with
> vectorization disabled, but {{0.0}} with vectorization enabled.
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