Fix #34: Database connection pool not configured with connection limits or error handling

[nandanadileep]

Summary

Fixes #34 by configuring the PostgreSQL connection pool with production-ready limits, timeouts, and error handling, and by adding graceful shutdown logic.

Problem

backend/src/database/client.ts created a Pool with only connectionString. Under load this can lead to:

• Connection exhaustion (default pool size may be too small)
• Idle connections not being cleaned up
• Unhandled database errors crashing the Node.js process
• Connections left open during deploys / SIGTERM shutdowns

Changes

• backend/src/database/client.ts

  • Added configurable pool limits:
    • DB_POOL_MAX (default 20)
    • DB_POOL_MIN (default 2)
    • DB_IDLE_TIMEOUT (default 30000 ms)
    • DB_CONNECTION_TIMEOUT (default 5000 ms)
  • Set allowExitOnIdle: false to keep the process alive while the pool is running
  • Added a pool.on('error', …) handler so idle-client errors are logged instead of crashing the process
  • Exported a new closePool() helper for clean shutdown

• backend/src/server.ts

  • Imported the database pool
  • Stored the server instance returned by app.listen
  • Added a SIGTERM handler that:
    1. Closes the database pool
    2. Closes the HTTP server
    3. Exits cleanly

Environment variables

No breaking changes. Existing deployments keep working because every new setting has a sensible default. Optional overrides:

Variable	Default	Description
DB_POOL_MAX	20	Maximum connections in the pool
DB_POOL_MIN	2	Minimum idle connections
DB_IDLE_TIMEOUT	30000	Milliseconds before an idle client is closed
DB_CONNECTION_TIMEOUT	5000	Milliseconds to wait when connecting

Testing

• Server starts normally with DATABASE_URL set
• Sending SIGTERM closes the pool and exits without open handles
• Pool error events are logged and do not crash the process

Related

• Closes Database connection pool not configured with connection limits or error handling #34

[ai-mountain]

@nandanadileep Thank you for your contributing.
But I hope u explain more details about description.

[ai-mountain]

@nandanadileep plz update Description before merging this PR.

[nandanadileep]

@RenzoMXD Updated the PR description with the details.

[ai-mountain]

@nandanadileep please fix ci test failing.

[ai-mountain]

Thanks for your contribution. @nandanadileep