Common Issues Troubleshooting Script¶

Overview¶

Troubleshooting guide script covering the most common issues in Azure Synapse Analytics and their solutions.

Common Issues¶

1. Authentication Failures¶

Symptom: "Login failed for user" error

Solution:

-- Check firewall rules
-- Verify Azure AD permissions
-- Ensure managed identity has access

2. Query Performance Issues¶

Symptoms: - Slow query execution - High resource consumption - Timeout errors

Solutions: - Check statistics: UPDATE STATISTICS table_name - Review distribution: DBCC PDW_SHOWSPACEUSED('table_name') - Analyze query plan: EXPLAIN SELECT ...

3. Pipeline Failures¶

Common Causes: - Timeout settings too low - Insufficient retry logic - Authentication issues - Resource constraints

Troubleshooting:

{
  "timeout": "0.12:00:00",
  "retry": 3,
  "retryIntervalInSeconds": 30
}

4. Spark Job Failures¶

Issues: - Out of memory errors - Data skew - Configuration problems

Solutions:

# Increase executor memory
spark.conf.set("spark.executor.memory", "8g")

# Handle skew
df.repartition(200, "skewed_column")

5. Data Lake Access Issues¶

Problems: - Permission denied - File not found - Slow reads

Checks: - RBAC assignments - ACL permissions - File paths correct - Storage account accessible

Diagnostic Queries¶

-- Check running queries
SELECT *
FROM sys.dm_pdw_exec_requests
WHERE status = 'Running';

-- View wait statistics
SELECT *
FROM sys.dm_pdw_waits
WHERE request_id = 'QID12345';

-- Check space usage
DBCC PDW_SHOWSPACEUSED;

Last Updated: January 2025