Learn about the Spark property used to configure automatic broadcasting of DataFrames below a certain size threshold. Prepare for the Databricks Certified Associate Developer for Apache Spark exam with this comprehensive explanation.
Table of Contents
Question
Which of the following Spark properties is used to configure whether DataFrames found to be below a certain size threshold at runtime will be automatically broadcasted?
A. spark.sql.broadcastTimeout
B. spark.sql.autoBroadcastJoinThreshold
C. spark.sql.shuffle.partitions
D. spark.sql.inMemoryColumnarStorage.batchSize
E. spark.sql.adaptive.localShuffleReader.enabled
Answer
B. spark.sql.autoBroadcastJoinThreshold
Explanation
The Spark property used to configure whether DataFrames found to be below a certain size threshold at runtime will be automatically broadcasted is:
B. spark.sql.autoBroadcastJoinThreshold
The `spark.sql.autoBroadcastJoinThreshold` property is used to set the maximum size (in bytes) for a table that will be broadcast to all worker nodes when performing a join. When the size of a DataFrame is below this threshold, Spark will automatically broadcast the smaller DataFrame to all worker nodes, optimizing the join operation by reducing the amount of data that needs to be shuffled across the network.
By default, the value of `spark.sql.autoBroadcastJoinThreshold` is 10485760 (10 MB). You can adjust this value based on your specific requirements and cluster resources. Setting this value to -1 disables the automatic broadcasting feature.
The other options mentioned in the question are used for different purposes:
- `spark.sql.broadcastTimeout`: Sets the timeout (in seconds) for broadcasting a DataFrame.
- `spark.sql.shuffle.partitions`: Configures the number of partitions to use when shuffling data for joins or aggregations.
- `spark.sql.inMemoryColumnarStorage.batchSize`: Sets the batch size (in bytes) for the columnar cache.
- `spark.sql.adaptive.localShuffleReader.enabled`: Enables or disables the use of local shuffle reader for adaptive query execution.
In summary, the `spark.sql.autoBroadcastJoinThreshold` property is the correct choice for configuring the automatic broadcasting of DataFrames below a certain size threshold in Apache Spark.
Databricks Certified Associate Developer for Apache Spark certification exam practice question and answer (Q&A) dump with detail explanation and reference available free, helpful to pass the Databricks Certified Associate Developer for Apache Spark exam and earn Databricks Certified Associate Developer for Apache Spark certification.