package main import( "fmt" "database/sql" _ "github.com/go-sql-driver/mysql" "log" ) var ( Id string Name string ) func main(){ db, err := sql.Open("mysql", "root:123456@tcp(127.0.0.1:3306)/go?charset=utf8") if err != nil { fmt.Println(err) return } defer db.Close() update(db) sqlselect(db) insert(db) fmt.Println("After inserting") sqlselect(db) delete(db); fmt.Println("After deleting") sqlselect(db) } // Query data func sqlselect(db *sql.DB) { rows,err := db.Query("select * from test") if err !

One:The code declared by go defer is not executed in the goroutine:package main import ( "fmt" "time" ) var ch chan int func main() { ch =make(chan int) for i:=0;i<10 ;i++ { go test(i) } for i:=0;i<10 ;i++ { <-ch } } func test(index int ){ time.Sleep(time.Second*1) defer fmt.Println("Exit test", index) ch<-index }operation result:Result 1: Exit test 5 Result 2: NothingIsn't it said that a good defer keyword means that it will always be executed? The result is that the defer keyword i

I just thought about the lock relationship of golang, thinking that the golang object lock acquired by the coroutine is acquired in chronological order, but it is not. Let's look at the code below. By the way, I wrote two applications for read-write locks.package main import ( "sync" "fmt" "time" ) //Open 10 threads at the same time to compete for a mutex lock who has the ability and who var mutex *sync.Mutex; var ch chan int func main() { mutex=new(sync.Mutex) fmt.Println("start") ch=make(chan

This article mainly introduces the application of game server to redis. Introduce some uses of the redis c++ client.Storage structure design:(1) Take the redis storage structure of equipment and props as an example (Hashes storage type)The storage structure is: key: EQUIPMENTBAG role id frield: equipment location value: equipment informationStore an equipment item to redis (using the hset command) Store all the items in the player's equipment backpack at once (using the command hmset) Get all th