Why is the B-tree index so popular and versatile?
Middle+
201
Golang
8386
379
How did you perform sharding in PostgreSQL? What hashing algorithm did you use?
Senior
199
Tell us a little about yourself. What do you do on your last project?
Middle+
196
Why was sharding by account_id chosen? What was the purpose of sharding?
Senior
195
What metrics did you monitor when consuming data from sources?
Middle+
194
How was your PostgreSQL deployed? Tell us about its stability and scalability.
Middle+
194
There is a database query function that returns the same value. Suggest a solution so that it does not go to the database unnecessarily for the same data.
Middle+
192
Did you work under a TK or a GPH contract at your last job?
Middle+
191
How do you monitor message order in Kafka? For example, if a status first flies, then a payment?
Middle+
191
What is index selectivity?
Senior
188
What will happen if you run 5 trillion goroutines? How to optimize?
Senior
188
What are the disadvantages of indexes? Can an index slow down reading?
Middle+
187
How did you approach versioning gRPC contracts?
Senior
186
Can an index slow down reading (SELECT)?
Senior
186
Why did you choose map for cache instead of sync.Map?
Middle+
185
If you looked at the warehouse leftovers, did you key in specific SKUs?
Middle+
183
Why did you use Mutex instead of Atomic for the counter?
Senior
183
Have you looked at large warehouses, and did dark stores also enter your analytics?
Middle+
183
How did you decide which parts to split the monolith into?
Senior
182
```go type User struct { ID int Name string } var ( dbHits int ) func getUserInfoFromDB(id int) User { time.Sleep(100 * time.Millisecond) dbHits++ return User{ID: id, Name: fmt.Sprintf("User-%d", id), } } func main() { var wg sync.WaitGroup for i := 0; i < 5; i++ { wg.Add(1) go func(i int) { defer wg.Done() fmt.Println(getUserInfoFromDB(i)) }(42) } wg.Wait() fmt.Println("DB hits:", dbHits) } ``` ```go func main() { var wg sync.WaitGroup j := 12345 for i := 0; i < 5000; i++ { wg.Add(1) go func(i int) { defer wg.Done() once.Do(func() { user = getUserInfoFromDB(42) }) fmt.Println(user) }(j) } wg.Wait() fmt.Println("DB hits:", dbHits) } ``` (There is no explicit question text, but the code suggests a task related to concurrency, synchronization, and minimizing database hits by using sync.Once or similar techniques.)
Middle+
182