spark.sql.shuffle.partitions 默认值为 200 spark.sql.shuffle.partitions 200 The default number of partitions to use when shuffling data for joins or aggregations. Note: For structured streaming, this configuration cannot be changed between query restarts from the same checkpoint location. 1. 2. 如果...
objectQueryPlanningTracker{// Define a list of common phases here.valPARSING="parsing"valANALYSIS="analysis"valOPTIMIZATION="optimization"valPLANNING="planning" 2.3执行计划查看 前面spark.sql()返回的是一个DataFrame对象,而DataFrame是个一种特殊的DataSet(DataSet[Row]),DataSet中的explain方法可以查看相应的执...
* access to the intermediate phases of query execution for developers. * * While this is not a public class, we should avoid changing the function names for the sake of * changing them, because a lot of developers use the feature for debugging. */ class QueryExecution(val sqlContext: SQL...
Referenční informace k tabulce HDInsightSparkSQLExecutionEvents v protokolech služby Azure Monitor
To support a wide variety of data sources and analytics workloads in Spark SQL, we designed an extensible query optimizer calledCatalyst. Catalyst uses features of the Scala programming language, such as pattern-matching, to express composable rules in a Turing-complete language. ...
.dir.recursive','true')\.config('spark.sql.hive.convertMetastoreOrc','false')\.config('spark.yarn.queue','datawarehouse')\.appName('yqj test')\.enableHiveSupport()\.getOrCreate()sql="select count(*) from ods.check_hive2_not_delete group by cityid"sql_run=spark.sql(sql)sql_run....
org.apache.spark spark-sql_2.12 3.3.1.5.2-106693326 org.apache.spark spark-sql-kafka-0-10_2.12 3.3.1.5.2-106693326 org.apache.spark spark-streaming_2.12 3.3.1.5.2-106693326 org.apache.spark spark-streaming-kafka-0-10-assembly_2.12 3.3.1.5.2-106693326 org.apache.spark spark-tags_2.12 3.3...
Dataframe use catalyst tree transformation framework in four phases, 1.Analyzing a logical plan to resolve references 2.Logical plan optimization 3.Physical planning 4.Code generation to compile parts of the query to Java bytecode. Hive Compatibility: Using Spark SQL, you can run unmodified Hive...
37. What are Spark Datasets? Datasets are data structures in Spark (added since Spark 1.6) that provide the JVM object benefits of RDDs (the ability to manipulate data with lambda functions), alongside a Spark SQL-optimized execution engine.38. Which languages can Spark be integrated with?
Using index in a query is transparent. When SQL queries have filter conditions on the column(s) which can take advantage of the index to filter the data scan, the index will automatically be applied to the execution of Spark SQL. The following example will automatically use the underlayer...