26ae9e93da
### What changes were proposed in this pull request?
This PR proposes to move distributed-sequence index implementation to SQL plan to leverage optimizations such as column pruning.
```python
import pyspark.pandas as ps
ps.set_option('compute.default_index_type', 'distributed-sequence')
ps.range(10).id.value_counts().to_frame().spark.explain()
```
**Before:**
```bash
== Physical Plan ==
AdaptiveSparkPlan isFinalPlan=false
+- Sort [count#51L DESC NULLS LAST], true, 0
+- Exchange rangepartitioning(count#51L DESC NULLS LAST, 200), ENSURE_REQUIREMENTS, [id=#70]
+- HashAggregate(keys=[id#37L], functions=[count(1)], output=[__index_level_0__#48L, count#51L])
+- Exchange hashpartitioning(id#37L, 200), ENSURE_REQUIREMENTS, [id=#67]
+- HashAggregate(keys=[id#37L], functions=[partial_count(1)], output=[id#37L, count#63L])
+- Project [id#37L]
+- Filter atleastnnonnulls(1, id#37L)
+- Scan ExistingRDD[__index_level_0__#36L,id#37L]
# ^^^ Base DataFrame created by the output RDD from zipWithIndex (and checkpointed)
```
**After:**
```bash
== Physical Plan ==
AdaptiveSparkPlan isFinalPlan=false
+- Sort [count#275L DESC NULLS LAST], true, 0
+- Exchange rangepartitioning(count#275L DESC NULLS LAST, 200), ENSURE_REQUIREMENTS, [id=#174]
+- HashAggregate(keys=[id#258L], functions=[count(1)])
+- HashAggregate(keys=[id#258L], functions=[partial_count(1)])
+- Filter atleastnnonnulls(1, id#258L)
+- Range (0, 10, step=1, splits=16)
# ^^^ Removed the Spark job execution for `zipWithIndex`
```
### Why are the changes needed?
To leverage optimization of SQL engine and avoid unnecessary shuffle to create default index.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
Unittests were added. Also, this PR will test all unittests in pandas API on Spark after switching the default index implementation to `distributed-sequence`.
Closes #33807 from HyukjinKwon/SPARK-36559.
Authored-by: Hyukjin Kwon <gurwls223@apache.org>
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>
(cherry picked from commit
|
||
|---|---|---|
| .. | ||
| catalyst | ||
| core | ||
| hive | ||
| hive-thriftserver | ||
| create-docs.sh | ||
| gen-sql-api-docs.py | ||
| gen-sql-config-docs.py | ||
| gen-sql-functions-docs.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, and SQL configuration documentation that gets included as part of configuration.md in the main docs directory.