What is your experience with databases? What tasks have you solved with PostgreSQL, ClickHouse, and Redis?

In working with PostgreSQL, I often encountered tasks related to storing and processing transactional data, building complex queries using JOIN, window functions, and CTEs for analytics. For example, I implemented an order tracking system with change history and reports.

I used ClickHouse for high-performance analytics of large data volumes in real-time. Tasks included log aggregation, dashboard creation with metrics, and query optimization using partitioning and indexes.

Redis was used as a cache to speed up access to frequently requested data, as well as for implementing queues and locking mechanisms. For example, I implemented rate limiting and user session storage with TTL.

Example of using Redis for caching in Go:

client := redis.NewClient(&redis.Options{
    Addr: "localhost:6379",
})

// Setting a value with TTL
err := client.Set(ctx, "user:123", "data", time.Minute*10).Err()
if err != nil {
    log.Fatal(err)
}

// Getting a value
val, err := client.Get(ctx, "user:123").Result()
if err != nil {
    log.Fatal(err)
}
fmt.Println(val)