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https://issues.apache.org/jira/browse/SPARK-19737?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Cheng Lian updated SPARK-19737:
-------------------------------
Description:
Let's consider the following simple SQL query that reference an undefined
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 invocations
# Look up the function names from the function registry
# Report analysis error for any unregistered functions
Since this rule doesn't actually try to 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 and make sure it gets executed before {{ResolveRelations}}.
was:
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 invocations
# Look up the function names from the function registry
# Report analysis error for any unregistered functions
Since this rule doesn't actually try to 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 and make sure it gets executed before {{ResolveRelations}}.
> 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 undefined
> 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 invocations
> # Look up the function names from the function registry
> # Report analysis error for any unregistered functions
> Since this rule doesn't actually try to 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 and make sure it gets executed before {{ResolveRelations}}.
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