4f10e54ba3
### What changes were proposed in this pull request?
In order to avoid frequently changing the value of `spark.sql.adaptive.shuffle.maxNumPostShufflePartitions`, we usually set `spark.sql.adaptive.shuffle.maxNumPostShufflePartitions` much larger than `spark.sql.shuffle.partitions` after enabling adaptive execution, which causes some bucket map join lose efficacy and add more `ShuffleExchange`.
How to reproduce:
```scala
val bucketedTableName = "bucketed_table"
spark.range(10000).write.bucketBy(500, "id").sortBy("id").mode(org.apache.spark.sql.SaveMode.Overwrite).saveAsTable(bucketedTableName)
val bucketedTable = spark.table(bucketedTableName)
val df = spark.range(8)
spark.conf.set("spark.sql.autoBroadcastJoinThreshold", -1)
// Spark 2.4. spark.sql.adaptive.enabled=false
// We set spark.sql.shuffle.partitions <= 500 every time based on our data in this case.
spark.conf.set("spark.sql.shuffle.partitions", 500)
bucketedTable.join(df, "id").explain()
// Since 3.0. We enabled adaptive execution and set spark.sql.adaptive.shuffle.maxNumPostShufflePartitions to a larger values to fit more cases.
spark.conf.set("spark.sql.adaptive.enabled", true)
spark.conf.set("spark.sql.adaptive.shuffle.maxNumPostShufflePartitions", 1000)
bucketedTable.join(df, "id").explain()
```
```
scala> bucketedTable.join(df, "id").explain()
== Physical Plan ==
*(4) Project [id#5L]
+- *(4) SortMergeJoin [id#5L], [id#7L], Inner
:- *(1) Sort [id#5L ASC NULLS FIRST], false, 0
: +- *(1) Project [id#5L]
: +- *(1) Filter isnotnull(id#5L)
: +- *(1) ColumnarToRow
: +- FileScan parquet default.bucketed_table[id#5L] Batched: true, DataFilters: [isnotnull(id#5L)], Format: Parquet, Location: InMemoryFileIndex[file:/root/opensource/apache-spark/spark-3.0.0-SNAPSHOT-bin-3.2.0/spark-warehou..., PartitionFilters: [], PushedFilters: [IsNotNull(id)], ReadSchema: struct<id:bigint>, SelectedBucketsCount: 500 out of 500
+- *(3) Sort [id#7L ASC NULLS FIRST], false, 0
+- Exchange hashpartitioning(id#7L, 500), true, [id=#49]
+- *(2) Range (0, 8, step=1, splits=16)
```
vs
```
scala> bucketedTable.join(df, "id").explain()
== Physical Plan ==
AdaptiveSparkPlan(isFinalPlan=false)
+- Project [id#5L]
+- SortMergeJoin [id#5L], [id#7L], Inner
:- Sort [id#5L ASC NULLS FIRST], false, 0
: +- Exchange hashpartitioning(id#5L, 1000), true, [id=#93]
: +- Project [id#5L]
: +- Filter isnotnull(id#5L)
: +- FileScan parquet default.bucketed_table[id#5L] Batched: true, DataFilters: [isnotnull(id#5L)], Format: Parquet, Location: InMemoryFileIndex[file:/root/opensource/apache-spark/spark-3.0.0-SNAPSHOT-bin-3.2.0/spark-warehou..., PartitionFilters: [], PushedFilters: [IsNotNull(id)], ReadSchema: struct<id:bigint>, SelectedBucketsCount: 500 out of 500
+- Sort [id#7L ASC NULLS FIRST], false, 0
+- Exchange hashpartitioning(id#7L, 1000), true, [id=#92]
+- Range (0, 8, step=1, splits=16)
```
This PR makes read bucketed tables always obeys `spark.sql.shuffle.partitions` even enabling adaptive execution and set `spark.sql.adaptive.shuffle.maxNumPostShufflePartitions` to avoid add more `ShuffleExchange`.
### Why are the changes needed?
Do not degrade performance after enabling adaptive execution.
### Does this PR introduce any user-facing change?
No.
### How was this patch tested?
Unit test.
Closes #26409 from wangyum/SPARK-29655.
Authored-by: Yuming Wang <yumwang@ebay.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
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|---|---|---|
| .. | ||
| catalyst | ||
| core | ||
| hive | ||
| hive-thriftserver | ||
| create-docs.sh | ||
| gen-sql-markdown.py | ||
| mkdocs.yml | ||
| README.md | ||
Spark SQL
This module provides support for executing relational queries expressed in either SQL or the DataFrame/Dataset API.
Spark SQL is broken up into four subprojects:
- Catalyst (sql/catalyst) - An implementation-agnostic framework for manipulating trees of relational operators and expressions.
- Execution (sql/core) - A query planner / execution engine for translating Catalyst's logical query plans into Spark RDDs. This component also includes a new public interface, SQLContext, that allows users to execute SQL or LINQ statements against existing RDDs and Parquet files.
- Hive Support (sql/hive) - Includes extensions that allow users to write queries using a subset of HiveQL and access data from a Hive Metastore using Hive SerDes. There are also wrappers that allow users to run queries that include Hive UDFs, UDAFs, and UDTFs.
- HiveServer and CLI support (sql/hive-thriftserver) - Includes support for the SQL CLI (bin/spark-sql) and a HiveServer2 (for JDBC/ODBC) compatible server.
Running ./sql/create-docs.sh generates SQL documentation for built-in functions under sql/site.