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https://issues.apache.org/jira/browse/SPARK-19093?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15803623#comment-15803623
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Josh Rosen commented on SPARK-19093:
------------------------------------
I'm not sure whether that's the case because I seemed to observe the cache
resolving when using subqueries for regular joins. We should play around with
it and see, though.
> LeftAntiJoin doesn't seem to resolve cached tables on right side
> ----------------------------------------------------------------
>
> Key: SPARK-19093
> URL: https://issues.apache.org/jira/browse/SPARK-19093
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 2.1.0
> Reporter: Josh Rosen
>
> See reproduction at
> https://databricks-prod-cloudfront.cloud.databricks.com/public/4027ec902e239c93eaaa8714f173bcfc/1903098128019500/2699761537338853/1395282846718893/latest.html
> Consider the following:
> {code}
> Seq(("a", "b"), ("c", "d"))
> .toDS
> .write
> .parquet("/tmp/rows")
> val df = spark.read.parquet("/tmp/rows")
> df.cache()
> df.count()
> df.createOrReplaceTempView("rows")
> spark.sql("""
> select * from rows cross join rows
> """).explain(true)
> spark.sql("""
> select * from rows where not exists (select * from rows)
> """).explain(true)
> {code}
> In both plans, I'd expect that both sides of the joins would read from the
> cached table for both the cross join and anti join, but the left anti join
> produces the following plan which only reads the left side from cache and
> reads the right side via a regular non-cahced scan:
> {code}
> == Parsed Logical Plan ==
> 'Project [*]
> +- 'Filter NOT exists#3994
> : +- 'Project [*]
> : +- 'UnresolvedRelation `rows`
> +- 'UnresolvedRelation `rows`
> == Analyzed Logical Plan ==
> _1: string, _2: string
> Project [_1#3775, _2#3776]
> +- Filter NOT predicate-subquery#3994 []
> : +- Project [_1#3775 AS _1#3775#4001, _2#3776 AS _2#3776#4002]
> : +- Project [_1#3775, _2#3776]
> : +- SubqueryAlias rows
> : +- Relation[_1#3775,_2#3776] parquet
> +- SubqueryAlias rows
> +- Relation[_1#3775,_2#3776] parquet
> == Optimized Logical Plan ==
> Join LeftAnti
> :- InMemoryRelation [_1#3775, _2#3776], true, 10000, StorageLevel(disk,
> memory, deserialized, 1 replicas)
> : +- *FileScan parquet [_1#3775,_2#3776] Batched: true, Format: Parquet,
> Location: InMemoryFileIndex[dbfs:/tmp/rows], PartitionFilters: [],
> PushedFilters: [], ReadSchema: struct<_1:string,_2:string>
> +- Project [_1#3775 AS _1#3775#4001, _2#3776 AS _2#3776#4002]
> +- Relation[_1#3775,_2#3776] parquet
> == Physical Plan ==
> BroadcastNestedLoopJoin BuildRight, LeftAnti
> :- InMemoryTableScan [_1#3775, _2#3776]
> : +- InMemoryRelation [_1#3775, _2#3776], true, 10000, StorageLevel(disk,
> memory, deserialized, 1 replicas)
> : +- *FileScan parquet [_1#3775,_2#3776] Batched: true, Format:
> Parquet, Location: InMemoryFileIndex[dbfs:/tmp/rows], PartitionFilters: [],
> PushedFilters: [], ReadSchema: struct<_1:string,_2:string>
> +- BroadcastExchange IdentityBroadcastMode
> +- *Project [_1#3775 AS _1#3775#4001, _2#3776 AS _2#3776#4002]
> +- *FileScan parquet [_1#3775,_2#3776] Batched: true, Format: Parquet,
> Location: InMemoryFileIndex[dbfs:/tmp/rows], PartitionFilters: [],
> PushedFilters: [], ReadSchema: struct<_1:string,_2:string>
> {code}
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