How to measure the execution time of a query on Sp

问题:

I need to measure the execution time of query on Apache spark (Bluemix). What I tried:

import time

startTimeQuery = time.clock()
df = sqlContext.sql(query)
df.show()
endTimeQuery = time.clock()
runTimeQuery = endTimeQuery - startTimeQuery

Is it a good way? The time that I get looks too small relative to when I see the table.

回答1:

Update: No, using time package is not the best way to measure execution time of Spark jobs. The most convenient and exact way I know of is to use the Spark History Server.

On Bluemix, in your notebooks go to the "Paelette" on the right side. Choose the "Evironment" Panel and you will see a link to the Spark History Server, where you can investigate the performed Spark jobs including computation times.

回答2:

To do it in the commandline, you can use spark.time().

See another response by me: https://stackoverflow.com/a/50289329/3397114

df = sqlContext.sql(query)
spark.time(df.show())

The output would be:

+----+----+
|col1|col2|
+----+----+
|val1|val2|
+----+----+
Time taken: xxx ms

Related: On Measuring Apache Spark Workload Metrics for Performance Troubleshooting.

回答3:

I use System.nanoTime wrapped around a helper function, like this -

def time[A](f: => A) = {
  val s = System.nanoTime
  val ret = f
  println("time: "+(System.nanoTime-s)/1e6+"ms")
  ret
}

time {
  df = sqlContext.sql(query)
  df.show()
}

回答4:

SPARK itself provides much granular information about each stage of your Spark Job.

You can view your running job on http://IP-MasterNode:4040 or You can enable History server for analyzing the jobs at a later time.

Refer here for more info on History server.