Here’s an overview of common Databricks production workload issues, along with causes, diagnostics, and resolutions, grouped by category:

🚨 1. Job Failures

🔹 Causes:

  • Schema changes in source data
  • Incompatible Delta Lake version
  • Missing libraries or Python dependencies
  • Code errors (e.g., AttributeError, KeyError)
  • Null pointer or divide-by-zero in transformations

🔍 Diagnostics:

  • Review job run logs under “Runs” tab
  • Check Cluster logs (Driver & Worker)
  • Use %run notebooks for reusable code & modular debugging

🛠️ Resolutions:

  • Enable Schema Evolution if using AutoLoader or Delta
  • Use try/except blocks with proper logging
  • Pin Python and library versions using requirements.txt

⚡ 2. Performance Degradation

🔹 Causes:

  • Skewed joins or wide transformations
  • Inefficient caching or checkpointing
  • High shuffle volume
  • Overpartitioning or underpartitioning

🔍 Diagnostics:

  • Use Spark UI (Tasks > Stages > SQL tab)
  • Analyze Shuffle size, task skew, and GC time
  • Metrics from Ganglia or Datadog

🛠️ Resolutions:

  • Use broadcast joins where applicable
  • Use repartition() and coalesce() wisely
  • Cache only if reused multiple times
  • Use Delta Z-Ordering and OPTIMIZE for storage reads

⏳ 3. Cluster Issues

🔹 Causes:

  • Autoscaling delays or failures
  • Improper driver memory allocation
  • Too many concurrent jobs or interactive notebooks

🔍 Diagnostics:

  • Monitor with Cluster Event Logs
  • Analyze Ganglia for CPU, memory, disk I/O
  • Review autoscaling logs and cluster termination history

🛠️ Resolutions:

  • Use Job Clusters for scheduled runs
  • Use interactive clusters only for dev
  • Choose the right VM size (e.g., memory-optimized for joins)
  • Set spark.dynamicAllocation.enabled = true

🔐 4. Access & Permission Errors

🔹 Causes:

  • Missing ACLs on data, notebooks, or clusters
  • Incorrect workspace group settings
  • Token/secret scope expiration

🔍 Diagnostics:

  • Review error messages (403, 401, or PERMISSION_DENIED)
  • Check access logs via Audit Logs

🛠️ Resolutions:

  • Use Unity Catalog or Cluster ACLs
  • Manage secrets via Databricks Secret Manager
  • Regularly rotate access tokens

💥 5. Delta Table Corruption / Conflicts

🔹 Causes:

  • Concurrent writes without isolation
  • Improper merge logic
  • Compaction conflicts

🔍 Diagnostics:

  • delta.log shows conflicting commits
  • Errors like ConcurrentAppendException or MissingFilesException

🛠️ Resolutions:

  • Use MERGE INTO with conditionals and ensure idempotency
  • Enable Deletion Vectors for soft deletes
  • Periodically run VACUUM and OPTIMIZE

✅ Best Practices for Production Stability

  1. Code Versioning: Use Git-integrated repos and CI/CD pipelines.
  2. Job Monitoring: Setup alerts with Datadog or Prometheus.
  3. Retries & Alerts: Enable automatic retries for jobs with Slack/Email alerts.
  4. Use AutoLoader: For robust schema evolution and ingestion.
  5. Cluster Policies: Enforce consistent configurations via Admin > Policies.