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Posted to issues@spark.apache.org by "Xiao Li (JIRA)" <ji...@apache.org> on 2016/02/09 07:22:18 UTC
[jira] [Issue Comment Deleted] (SPARK-13219) Pushdown predicate
propagation in SparkSQL with join
[ https://issues.apache.org/jira/browse/SPARK-13219?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Xiao Li updated SPARK-13219:
----------------------------
Comment: was deleted
(was: Could you wait for me to fix another issue? When I tried your query, I found a bug of attribute resolution in the latest build. I need to fix it now. Thanks!)
> Pushdown predicate propagation in SparkSQL with join
> ----------------------------------------------------
>
> Key: SPARK-13219
> URL: https://issues.apache.org/jira/browse/SPARK-13219
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 1.4.1, 1.6.0
> Environment: Spark 1.4
> Datastax Spark connector 1.4
> Cassandra. 2.1.12
> Centos 6.6
> Reporter: Abhinav Chawade
>
> When 2 or more tables are joined in SparkSQL and there is an equality clause in query on attributes used to perform the join, it is useful to apply that clause on scans for both table. If this is not done, one of the tables results in full scan which can reduce the query dramatically. Consider following example with 2 tables being joined.
> {code}
> CREATE TABLE assets (
> assetid int PRIMARY KEY,
> address text,
> propertyname text
> )
> CREATE TABLE tenants (
> assetid int PRIMARY KEY,
> name text
> )
> spark-sql> explain select t.name from tenants t, assets a where a.assetid = t.assetid and t.assetid='1201';
> WARN 2016-02-05 23:05:19 org.apache.hadoop.util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
> == Physical Plan ==
> Project [name#14]
> ShuffledHashJoin [assetid#13], [assetid#15], BuildRight
> Exchange (HashPartitioning 200)
> Filter (CAST(assetid#13, DoubleType) = 1201.0)
> HiveTableScan [assetid#13,name#14], (MetastoreRelation element, tenants, Some(t)), None
> Exchange (HashPartitioning 200)
> HiveTableScan [assetid#15], (MetastoreRelation element, assets, Some(a)), None
> Time taken: 1.354 seconds, Fetched 8 row(s)
> {code}
> The simple workaround is to add another equality condition for each table but it becomes cumbersome. It will be helpful if the query planner could improve filter propagation.
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