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From "Eyal Zituny (JIRA)" <j...@apache.org>
Subject [jira] [Created] (SPARK-21443) Very long planning duration for queries with lots of operations
Date Mon, 17 Jul 2017 14:54:00 GMT
Eyal Zituny created SPARK-21443:
-----------------------------------

             Summary: Very long planning duration for queries with lots of operations
                 Key: SPARK-21443
                 URL: https://issues.apache.org/jira/browse/SPARK-21443
             Project: Spark
          Issue Type: Bug
          Components: SQL, Structured Streaming
    Affects Versions: 2.2.0
            Reporter: Eyal Zituny


Creating a streaming query with large amount of operations and fields (100+) results in a
very long query planning phase. in the example bellow, the plan phase has taken 35 seconds
while the actual batch execution took only 1.3 second.
after some investigation, i have found out that the root causes of this are 2 optimizer rules
which seems to take most of the planning time: InferFiltersFromConstraints and PruneFilters

I would suggest the following:
# fix the inefficient optimizer rules
# add warn level logging if a rule has taken more then xx ms
# allow custom removing of optimizer rules (opposite to spark.experimental.extraOptimizations)
# reuse query plans (optional) where possible

reproducing this issue can be done with the bellow script which simulates the scenario:


{code:java}
import org.apache.spark.sql.SparkSession
import org.apache.spark.sql.execution.streaming.MemoryStream
import org.apache.spark.sql.streaming.StreamingQueryListener.{QueryProgressEvent, QueryStartedEvent,
QueryTerminatedEvent}
import org.apache.spark.sql.streaming.{ProcessingTime, StreamingQueryListener}

case class Product(pid: Long, name: String, price: Long, ts: Long = System.currentTimeMillis())

case class Events (eventId: Long, eventName: String, productId: Long) {
	def this(id: Long) = this(id, s"event$id", id%100)
}

object SparkTestFlow {
	def main(args: Array[String]): Unit = {
		val spark = SparkSession
		  .builder
		  .appName("TestFlow")
		  .master("local[8]")
		  .getOrCreate()

		spark.sqlContext.streams.addListener(new StreamingQueryListener {
			override def onQueryTerminated(event: QueryTerminatedEvent): Unit = {}
			override def onQueryProgress(event: QueryProgressEvent): Unit = {
				if (event.progress.numInputRows>0) {
					println(event.progress.toString())
				}
			}
			override def onQueryStarted(event: QueryStartedEvent): Unit = {}
		})
		
		import spark.implicits._
		implicit val  sclContext = spark.sqlContext
		import org.apache.spark.sql.functions.expr

		val seq = (1L to 100L).map(i => Product(i, s"name$i", 10L*i))
		val lookupTable = spark.createDataFrame(seq)

		val inputData = MemoryStream[Events]
		inputData.addData((1L to 100L).map(i => new Events(i)))

		val events = inputData.toDF()
		  .withColumn("w1", expr("0"))
		  .withColumn("x1", expr("0"))
		  .withColumn("y1", expr("0"))
		  .withColumn("z1", expr("0"))

		val numberOfSelects = 40 // set to 100+ and the planning takes forever
		val dfWithSelectsExpr = (2 to numberOfSelects).foldLeft(events)((df,i) =>{
			val arr = df.columns.++(Array(s"w${i-1} + rand() as w$i", s"x${i-1} + rand() as x$i", s"y${i-1}
+ 2 as y$i", s"z${i-1} +1 as z$i"))
			df.selectExpr(arr:_*)
		})

		val withJoinAndFilter = dfWithSelectsExpr
		  .join(lookupTable, expr("productId = pid"))
		  .filter("productId < 50")

		val query = withJoinAndFilter.writeStream
		  .outputMode("append")
		  .format("console")
		  .trigger(ProcessingTime(2000))
		  .start()

		query.processAllAvailable()
		spark.stop()
	}
}
{code}


the query progress output will show: 

{code:java}
"durationMs" : {
    "addBatch" : 1310,
    "getBatch" : 6,
    "getOffset" : 0,
    "*queryPlanning*" : 36924,
    "triggerExecution" : 38297,
    "walCommit" : 33
  }
{code}




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