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Posted to issues@spark.apache.org by "Dongjoon Hyun (JIRA)" <ji...@apache.org> on 2016/07/04 07:32:11 UTC
[jira] [Created] (SPARK-16360) Speed up SQL query performance by
removing redundant analysis in `Dataset`
Dongjoon Hyun created SPARK-16360:
-------------------------------------
Summary: Speed up SQL query performance by removing redundant analysis in `Dataset`
Key: SPARK-16360
URL: https://issues.apache.org/jira/browse/SPARK-16360
Project: Spark
Issue Type: Improvement
Components: SQL
Reporter: Dongjoon Hyun
Currently, there are a few reports about Spark 2.0 query performance regression for large queries.
This issue speeds up SQL query processing performance by removing redundant consecutive analysis in `Dataset.ofRows` function and `Dataset` instantiation. Specifically, this issue aims to reduce the overhead of SQL query analysis, not query execution.
**Before**
{code}
scala> :pa
// Entering paste mode (ctrl-D to finish)
val n = 4000
val values = (1 to n).map(_.toString).mkString(", ")
val columns = (1 to n).map("column" + _).mkString(", ")
val query =
s"""
|SELECT $columns
|FROM VALUES ($values) T($columns)
|WHERE 1=2 AND 1 IN ($columns)
|GROUP BY $columns
|ORDER BY $columns
|""".stripMargin
def time[R](block: => R): R = {
val t0 = System.nanoTime()
val result = block
println("Elapsed time: " + ((System.nanoTime - t0) / 1e9) + "s")
result
}
time(sql(query))
time(sql(query))
// Exiting paste mode, now interpreting.
Elapsed time: 30.138142577s
Elapsed time: 25.787751452s
{code}
**After**
{code}
Elapsed time: 17.500279659s
Elapsed time: 12.364812255s
{code}
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