Understanding and Troubleshooting Intermittent Connection Timeouts in a Laravel, MariaDB, and Redis Environment

If you’re running a Laravel-based real estate listing platform with automated CRM integrations, encountering sporadic connection timeouts and slow job processing can significantly impact your application’s reliability. Here’s a comprehensive overview of common issues, potential causes, and practical strategies to diagnose and resolve these challenges.

Scenario Overview

Your setup:
– Application: Laravel framework managing property listings
– Database: MariaDB hosted on the same VPS
– Caching & Queue Management: Redis
– Hardware: Single VPS with 8 cores and 16 GB RAM
– Traffic: Low to moderate, averaging around 20 visits per minute with occasional spikes from bots
– Operations: Daily automated offers imports from multiple external CRMs, and API calls to a headless WordPress instance for blog content

Current Observations

1. Job Timeouts: Laravel jobs sometimes exceed the 600-second limit, despite typically completing within half a second during normal conditions.
2. API Connectivity Issues: Curl requests to the WordPress API occasionally fail with connection timeouts.
3. Connection Stability: Indications suggest possible intermittent disruptions between the app and the database.

Configurations & Diagnostics Conducted So Far

• PHP Pooling: Properly configured with sufficient pools, avoiding exhaustion under peak loads.
• MariaDB Settings: Connection limits are not saturated; max connections and timeout settings are within reasonable bounds.
• Slow Query Log: Enabled to identify long-running queries; logs show no significant delays or blocked processes.

Potential Causes & Troubleshooting Strategies

1. Network and Resource Limitations
2. Since app and database reside on the same VPS, network latency is less likely but still possible during resource contention.

3. Monitor server resource utilization (CPU, RAM, disk I/O) to identify bottlenecks.

4. MariaDB and Redis Connection Management

5. Verify the connection pool settings and ensure they are optimized for your workload.

6. Consider increasing the ‘wait_timeout’ and ‘interactive_timeout’ parameters, but only if connection drops are observed.

7. Application-Level Issues

8. Review code for unhandled exceptions or long-running loops that may cause jobs to hang.

9. Implement more granular logging within your Laravel jobs to pinpoint where delays or failures occur.

10. External API Calls

11. Curl timeouts can stem from network latency or rate-limiting on the WordPress API.
12. Introduce retries and exponential backoff mechanisms to improve resilience