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https://issues.apache.org/jira/browse/SPARK-19290?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15830031#comment-15830031
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Wenchen Fan edited comment on SPARK-19290 at 1/19/17 2:29 PM:
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sorry my modification to the title failed because of network problems, now I've
updated the title and added the description.
was (Author: cloud_fan):
sorry my modification to the title failed because of network problems, not I've
updated the title and added the description.
> add a new extending interface in Analyzer for post-hoc resolution
> -----------------------------------------------------------------
>
> Key: SPARK-19290
> URL: https://issues.apache.org/jira/browse/SPARK-19290
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Reporter: Wenchen Fan
> Assignee: Wenchen Fan
>
> To implement DDL commands, we added several analyzer rules in sql/hive module
> to analyze DDL related plans. However, our Analyzer currently only have one
> extending interface: extendedResolutionRules, which defines extra rules that
> will be run together with other rules in the resolution batch, and doesn't
> fit DDL rules well, because:
> 1. DDL rules may do some checking and normalization, but we may do it many
> times as the resolution batch will run rules again and again, until fixed
> point, and it's hard to tell if a DDL rule has already done its checking and
> normalization. It's fine because DDL rules are idempotent, but it's bad for
> analysis performance
> 2. some DDL rules may depend on others, and it's pretty hard to write if
> conditions to guarantee the dependencies. It will be good if we have a batch
> which run rules in one pass, so that we can guarantee the dependencies by
> rules order.
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