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https://issues.apache.org/jira/browse/HIVE-1184?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Paul Yang updated HIVE-1184:
----------------------------
Attachment: HIVE-1184.1.patch
The problem stems from DefaultExprProcessor:process(). During the AST walk, any
error is cleared if a node matches a group by expression
{code}
...
exprNodeDesc desc = TypeCheckProcFactory.processGByExpr(nd, procCtx);
if (desc != null) {
ctx.setError(null);
return desc;
}
{code}
Clearing the error was probably an attempt to address the generation of false
errors during the DFS walk of the AST. Consider the AST fragment from the query
{code}
SELECT concat(src.key) FROM src GROUP BY concat(src.key)
TOK_FUNCTION
/ \
/ \
/ \
concat .
/ \
/ \
TOK_TABLE_OR_COL key
|
|
src
{code}
During the walk, process() will be called on src before TOK_FUNCTION. Because
src is not a group by expression, an error will be set in ctx. However, when
process() is called on TOK_FUNCTION, it matches the group by expression
'concat(src.key)' and the error is cleared, producing the expected behavior.
A problem arises with a query like
{code}
select concat(value, concat(value)) from src group by concat(value)
{code}
as the AST is such that 'value' (1st argument of outer concat) is processed
before 'concat(value)'. When process() acts on 'value', it sets an error
because it is not a group by expression. But then the error is cleared when
process() is called on 'concat(value)'. The error should not really be cleared
as it was generated outside of the group by expression.
The proposed solution is to keep track of the ASTNode that generated the error
and only clear the error when it was generated from a node within the group by
expression.
> Expression Not In Group By Key error is sometimes masked
> --------------------------------------------------------
>
> Key: HIVE-1184
> URL: https://issues.apache.org/jira/browse/HIVE-1184
> Project: Hadoop Hive
> Issue Type: Bug
> Affects Versions: 0.6.0
> Reporter: Paul Yang
> Assignee: Paul Yang
> Attachments: HIVE-1184.1.patch
>
>
> Depending on the order of expressions, the error message for a expression not
> in group key is not displayed; instead it is null.
> {code}
> hive> select concat(value, concat(value)) from src group by concat(value);
> FAILED: Error in semantic analysis: null
> hive> select concat(concat(value), value) from src group by concat(value);
> FAILED: Error in semantic analysis: line 1:29 Expression Not In Group By Key
> value
> {code}
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