When you should not use Apache Spark ? Explain with reason.

There are a few situations where it may not be appropriate to use Apache Spark, which is a powerful open-source big data processing framework:

1. Small Data: If the data you are working with is small enough that it can be easily processed by a single machine, then using Spark may be overkill. Spark is designed to handle large amounts of data, and its overhead may not be worth the investment for small data sets.
2. Low Latency: Spark is designed for batch processing and does not provide low latency for real-time data processing. If you need to process data in real-time, other technologies such as Apache Storm or Apache Flink may be more appropriate.
3. Limited Resources: Spark requires significant resources, including memory and CPU, to run effectively. If your cluster does not have enough resources to run Spark, it may not be able to perform as expected.
4. Complexity: Spark is a complex system with many components and configuration options. If your team is not familiar with Spark or big data processing in general, it may take a significant amount of time and resources to get up to speed and effectively use the framework.
5. Lack of Support: Spark is written in Scala and runs on the Java Virtual Machine (JVM). If you’re working with a non-JVM language like Python, you might need to do extra work to get the same functionality in Spark.
6. Limited scalability: Spark is designed to run on a cluster of machines, but it is not as well-suited for extremely large data sets as other technologies such as Apache Hadoop.

Spark is a powerful big data processing framework, but it may not be the best choice for every situation. It is important to evaluate the specific requirements of your project in the initial stage itself  and the resources available to determine whether Spark is the right choice for your use case.

Spark important urls to refer

1. Spark Examples
2. PySpark Blogs
3. Bigdata Blogs
4. Spark Interview Questions
5. Official Page