Error when connect database continuously

sql

retry-policies

database-connections

error-handling

byNikita Barsukov·Dec 3, 2024

To mitigate frequent database connection errors, follow these best practices:

Cleanup: Always close your connection using connection.close(), freeing up resources.
Efficiency: Implement connection pooling to reuse connections and reduce opening/closing cycles.
Exception handling: Use try...catch blocks for error management and ensure connections close using finally.
Manage context: Use using (C#) or with (Python) to automatically cleanup connections post operations.
Monitor resources: Regularly check your system resources to pre-empt potential issues.

Python example with with for automatic cleanup:

with psycopg2.connect(DSN) as conn:
    # Operations - connection autocloses like a magic trick!

Connections automatically close once an operation block ends, preventing persistent error loops.

Building resilient database connections

Continuously connecting to a database can lead to transient failures. It's crucial to implement resilient connection strategies like retry policies.

Set up a retry on failure strategy

Utilize EF Core's EnableRetryOnFailure to attempt reconnections. You can define the number of retries and the time intervals between them with the DbContextOptionsBuilder.

optionsBuilder
    .UseSqlServer(
        yourConnectionString,
        options => options.EnableRetryOnFailure(
            maxRetryCount: 5,
            maxRetryDelay: TimeSpan.FromSeconds(30),
            errorNumbersToAdd: null)); // Better luck next time!

Consider database specifics

When using SQL Azure, you can apply the SqlAzureExecutionStrategy, tuned to counter challenges such as load balancing and hardware failures.

Tweaking database performance

Minimize login errors: Under-spec'd resource tiers can impede your connectivity. Opt for higher tiers in production environments.
Diagnosing issues: Use the Azure portal tools to debug potential performance problems.
Know your service tier: The service tier of your Azure database impacts your performance through CPU throttling and request handleability.

Combating intermittent connectivity

Handling database session lifecycles carefully can ensure smooth operations amid intermittent connectivity issues. Here is a useful code pattern:

while(keepTrying) {
    try {
        using(var context = new YourDbContext()) {
            // Your database operations here
        }
        keepTrying = false; // Success! Time to take a nap.
    } catch (Exception ex) {
        logger.Log(ex); // Oopsie daisy!
        Thread.Sleep(retryInterval); // Pause, deep breath, and retry.
    }
}

Tips for code patterns:

No infinite loops: Define a clear exit condition for your retry mechanism.
Customize mechanisms: Tailor your retry strategies to match your database’s characteristics.
Uncover root causes: Investigate the underlying causes behind transient failures for fine-tuning your connection strategy.

Steps for steady database connectivity

Achieving a decent balance in resource utilization

Balanced connection usage: Either overuse or underuse of connections can trigger errors. Strive to find the right balance.
Connection health: Regularly monitor the state of your connections.

Employing a defensive programming approach

Exception handling: Code defensively by wrapping your database calls in a try-catch block.
Retry Logic: Implement a logic to determine when it's safe to retry an operation.