Introduction

Go SQL rows are not closed when defer rows. This guide provides step-by-step diagnosis and resolution with specific commands and code examples.

Symptoms

Typical symptoms and error messages when this issue occurs:

bash
sql: Rows not closed
rows.Close() not called

Observable indicators: - Application logs show connection or operation failures - Error messages appear in system or application logs - Related dependent services may exhibit cascading failures

Common Causes

  1. 1.Database connection issues are commonly caused by:
  2. 2.Incorrect connection string format
  3. 3.Missing driver registration in init()
  4. 4.Pool size mismatch with concurrent query load

Step-by-Step Fix

Step 1: Check Current State

bash
go version && go env

Step 2: Identify Root Cause

bash
go build -v ./...

Step 3: Apply Primary Fix

go
// Primary fix: update configuration
cfg := Config{
    Timeout:   30 * time.Second,
    MaxRetry:  3,
    LogLevel:  "info",
}

Apply this configuration and restart the application:

bash
go build && ./application

Step 4: Apply Alternative Fix (If Needed)

go
// Alternative fix: use context with timeout
ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()
result, err := operation.WithContext(ctx)

Monitor database connection metrics after changes: SHOW STATUS LIKE "Threads%";

Step 5: Verify the Fix

After applying the fix, verify with:

bash
go test -v ./pkg/database -run TestConnectionPool

Expected output should show successful operation without errors.

Common Pitfalls

  • Scanning NULL values into non-nullable types
  • Not closing rows.Rows after iteration
  • Using default pool size for high concurrency

Best Practices

  • Use context for all database operations
  • Close rows immediately after use
  • Set connection pool limits based on load
  • Go SQL Transaction Deadlock
  • Go SQL Null Value Handling Error
  • Go SQL Connection Refused