Common performance pitfalls in Elixir include excessive process creation, improper use of `:ets`, and inefficient database queries. Profiling and monitoring are essential to identify and address these issues.

When developing applications in Elixir, it's important to be aware of common performance pitfalls that can hinder the efficiency and scalability of your system. One significant issue is excessive process creation, which can lead to overhead and resource consumption. While Elixir processes are lightweight, spawning too many of them without a clear strategy can still impact performance. Instead, consider reusing existing processes or implementing process pooling to manage resources effectively. Another potential pitfall is the improper use of :ets. While :ets provides fast access to in-memory data, failing to manage the lifecycle of :ets tables and their data can lead to memory bloat and inefficiencies. It's crucial to implement cleanup strategies for unused tables and avoid retaining stale data. Additionally, inefficient database queries can significantly impact application performance. Use Ecto's query capabilities to construct optimized queries, and leverage indexing in your database to improve retrieval times. Regular profiling and monitoring of your application's performance can help you identify these issues early. Tools like :observer and :telemetry can provide insights into bottlenecks, allowing you to address them proactively. By being mindful of these common pitfalls, you can build Elixir applications that perform optimally under varying loads.