fabric-udf-perf-remediatelisted

# Microsoft Fabric User Data Functions Performance remediate Systematic guide for diagnosing and resolving performance issues with Fabric User Data Functions (UDFs). Covers cold starts, execution timeouts, capacity consumption, connection bottlenecks, and Python code optimization. ## When to Use This Skill - Function invocations are slow or intermittently timing out - Capacity metrics show unexpected CU consumption from UDF operations - Functions fail with timeout, response size, or connection errors - Cold start latency is impacting downstream consumers (Pipelines, Notebooks, Power BI) - Historical logs show increasing duration trends - Need to optimize UDF code for better performance within service limits ## Prerequisites - Access to the Fabric portal with permissions on the User Data Functions item - Microsoft Fabric Capacity Metrics app installed (for CU analysis) - Python 3.11+ locally (for code profiling outside Fabric) - PowerShell 7+ (for running diagnostic scripts) ## Service Limits Quick Reference | Limit | Value | Impact | | --------------------- | ----------- | -------------------------------- | | Request payload | 4 MB | All input parameters combined | | Execution timeout | 240 seconds | Maximum function runtime | | Response size | 30 MB | Maximum return value size | | Log retention | 30 days | Historical invocation log window | | Private library ma