spark-instrumented-optimizer/sql/core
Yuming Wang 7ffcfcf7db [SPARK-33847][SQL] Simplify CaseWhen if elseValue is None
### What changes were proposed in this pull request?

1. Enhance `ReplaceNullWithFalseInPredicate` to replace None of elseValue inside `CaseWhen` with `FalseLiteral` if all branches are `FalseLiteral` . The use case is:
```sql
create table t1 using parquet as select id from range(10);
explain select id from t1 where (CASE WHEN id = 1 THEN 'a' WHEN id = 3 THEN 'b' end) = 'c';
```

Before this pr:
```
== Physical Plan ==
*(1) Filter CASE WHEN (id#1L = 1) THEN false WHEN (id#1L = 3) THEN false END
+- *(1) ColumnarToRow
   +- FileScan parquet default.t1[id#1L] Batched: true, DataFilters: [CASE WHEN (id#1L = 1) THEN false WHEN (id#1L = 3) THEN false END], Format: Parquet, Location: InMemoryFileIndex[file:/Users/yumwang/opensource/spark/spark-warehouse/org.apache.spark.sql.DataF..., PartitionFilters: [], PushedFilters: [], ReadSchema: struct<id:bigint>

```

After this pr:
```
== Physical Plan ==
LocalTableScan <empty>, [id#1L]
```

2. Enhance `SimplifyConditionals` if elseValue is None and all outputs are null.

### Why are the changes needed?

Improve query performance.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

Unit test.

Closes #30852 from wangyum/SPARK-33847.

Authored-by: Yuming Wang <yumwang@ebay.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
2020-12-23 14:35:46 +00:00
..
benchmarks [SPARK-33523][SQL][TEST][FOLLOWUP] Fix benchmark case name in SubExprEliminationBenchmark 2020-11-25 15:22:47 -08:00
src [SPARK-33847][SQL] Simplify CaseWhen if elseValue is None 2020-12-23 14:35:46 +00:00
pom.xml [SPARK-33662][BUILD] Setting version to 3.2.0-SNAPSHOT 2020-12-04 14:10:42 -08:00