Given a code – How Catalyst Optimizer Works in This Code?
Vishal Jadhav You have the following code. Explain how the catalyst optimizer works in the code? Explain in detail PySpark’s Catalyst Optimizer is a powerful query optimizer used by Spark SQL to…
February 2025
Catalist optimizer : Prediction pushdown
if in your code/query if you are filterring the data at the end, Catalyst optimizer (in prediction pushdown) will apply filtering on input or source and then do the other…
What happens when you enable cache() in PySpark and the dataset exceeds the available memory? How does Spark handle this situation, and what potential issues might arise?
both cache() and persist() store data in memory to speed up the retrieval of intermediate data used for computation. However, persist() is more flexible and allows users to specify storage…
SCD Types Explained with Examples
Slowly Changing Dimensions (SCD) are used in data warehousing to manage historical changes in dimension tables. There are several types of SCDs, each handling data changes differently. Types of SCDs…
What is Spark Speculative Execution?
Set speculative execution configuration -> spark.speculation = True read more here
sql to pyspark query converstion
In this article, we are converting the SQL queries to Pyspark code Task SQL Command PySpark Command Selecting Data SELECT col1, col2 FROM table; df.select(“col1”, “col2”) Filtering Data SELECT *…
Pypark – Databriks + spark Rajas data engineering
PySpark Interview Questions (lec 6) How to read files in spark? You are going to see how to read different file formats in pyspark. first, you need to create the…
How would you handle skewed data in PySpark
Handling skewed data in PySpark is crucial for optimizing performance and ensuring efficient processing. Skewed data occurs when some partitions have significantly more data than others, leading to uneven workload…
Sliding Window Maximum (LeetCode 239)
Steps: 1. Iterate through the array nums from index 0 to len(nums) – k. 2. For each window of size k, find the maximum element. 3. Store the maximum value…
Valid Parentheses (LeetCode 20)
Given a string s containing just the characters '(', ')', '{', '}', '', determine if the input string is valid. An input string is valid if: Example 1: Input: s…