spark-instrumented-optimizer/sql/core/benchmarks
Dongjoon Hyun 103f513231 [SPARK-25306][SQL] Avoid skewed filter trees to speed up createFilter in ORC
## What changes were proposed in this pull request?

In both ORC data sources, `createFilter` function has exponential time complexity due to its skewed filter tree generation. This PR aims to improve it by using new `buildTree` function.

**REPRODUCE**
```scala
// Create and read 1 row table with 1000 columns
sql("set spark.sql.orc.filterPushdown=true")
val selectExpr = (1 to 1000).map(i => s"id c$i")
spark.range(1).selectExpr(selectExpr: _*).write.mode("overwrite").orc("/tmp/orc")
print(s"With 0 filters, ")
spark.time(spark.read.orc("/tmp/orc").count)

// Increase the number of filters
(20 to 30).foreach { width =>
  val whereExpr = (1 to width).map(i => s"c$i is not null").mkString(" and ")
  print(s"With $width filters, ")
  spark.time(spark.read.orc("/tmp/orc").where(whereExpr).count)
}
```

**RESULT**
```scala
With 0 filters, Time taken: 653 ms
With 20 filters, Time taken: 962 ms
With 21 filters, Time taken: 1282 ms
With 22 filters, Time taken: 1982 ms
With 23 filters, Time taken: 3855 ms
With 24 filters, Time taken: 6719 ms
With 25 filters, Time taken: 12669 ms
With 26 filters, Time taken: 25032 ms
With 27 filters, Time taken: 49585 ms
With 28 filters, Time taken: 98980 ms    // over 1 min 38 seconds
With 29 filters, Time taken: 198368 ms   // over 3 mins
With 30 filters, Time taken: 393744 ms   // over 6 mins
```

**AFTER THIS PR**
```scala
With 0 filters, Time taken: 774 ms
With 20 filters, Time taken: 601 ms
With 21 filters, Time taken: 399 ms
With 22 filters, Time taken: 679 ms
With 23 filters, Time taken: 363 ms
With 24 filters, Time taken: 342 ms
With 25 filters, Time taken: 336 ms
With 26 filters, Time taken: 352 ms
With 27 filters, Time taken: 322 ms
With 28 filters, Time taken: 302 ms
With 29 filters, Time taken: 307 ms
With 30 filters, Time taken: 301 ms
```

## How was this patch tested?

Pass the Jenkins with newly added test cases.

Closes #22313 from dongjoon-hyun/SPARK-25306.

Authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
2018-09-05 10:24:13 +08:00
..
FilterPushdownBenchmark-results.txt [SPARK-25306][SQL] Avoid skewed filter trees to speed up createFilter in ORC 2018-09-05 10:24:13 +08:00
WideSchemaBenchmark-results.txt [SPARK-17335][SQL] Fix ArrayType and MapType CatalogString. 2016-09-03 19:02:20 +02:00