Cheng Lian created SPARK-19737:
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             Summary: New analysis rule for reporting unregistered functions 
without relying on relation resolution
                 Key: SPARK-19737
                 URL: https://issues.apache.org/jira/browse/SPARK-19737
             Project: Spark
          Issue Type: Bug
          Components: SQL
    Affects Versions: 2.2.0
            Reporter: Cheng Lian
             Fix For: 2.2.0


Let's consider the following simple SQL query that reference an invalid 
function {{foo}} that is never registered in the function registry:
{code:sql}
SELECT foo(a) FROM t
{code}
Assuming table {{t}} is a partitioned  temporary view consisting of a large 
number of files stored on S3, then it may take the analyzer a long time before 
realizing that {{foo}} is not registered yet.

The reason is that the existing analysis rule {{ResolveFunctions}} requires all 
child expressions to be resolved first. Therefore, {{ResolveRelations}} has to 
be executed first to resolve all columns referenced by the unresolved function 
invocation. This further leads to partition discovery for {{t}}, which may take 
a long time.

To address this case, we propose a new lightweight analysis rule 
{{LookupFunctions}} that
# Matches all unresolved function invocation
# Look up the function name from the function registry
# Report analysis error for any unregistered functions

Since this rule doesn't try to actually resolve the unresolved functions, it 
doesn't rely on {{ResolveRelations}} and therefore doesn't trigger partition 
discovery.

We may put this analysis rule in a separate {{Once}} rule batch that sits 
between the "Substitution" batch and the "Resolution" batch to avoid running it 
repeatedly.



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