first commit

pool/pool_manager.go

@@ -0,0 +1,64 @@
+package pool
+
+import (
+	"fmt"
+	"sync"
+	"time"
+)
+
+// DBManager simulates a connection pool using a channel of "connections".
+type DBManager struct {
+	pool chan int
+}
+
+// NewDBManager creates a pool manager with capacity `cap`.
+func NewDBManager(cap int) *DBManager {
+	p := make(chan int, cap)
+	// initialize simulated connections IDs 1..cap
+	for i := 1; i <= cap; i++ {
+		p <- i
+	}
+	return &DBManager{pool: p}
+}
+
+// getConn pulls a connection id from pool (blocking if none available)
+func (m *DBManager) getConn() int {
+	return <-m.pool
+}
+
+// releaseConn returns a connection id to the pool
+func (m *DBManager) releaseConn(id int) {
+	m.pool <- id
+}
+
+// EksekusiQuery simulates executing a query: take connection, wait 1s, release.
+func (m *DBManager) EksekusiQuery(query string) string {
+	conn := m.getConn()
+	// Simulate query execution
+	time.Sleep(time.Second * 1)
+	m.releaseConn(conn)
+	return fmt.Sprintf("conn-%d executed: %s", conn, query)
+}
+
+// RunQueries launches n goroutines that call EksekusiQuery.
+// Returns list of responses in the order goroutines finished.
+func (m *DBManager) RunQueries(n int) []string {
+	var wg sync.WaitGroup
+	wg.Add(n)
+	resCh := make(chan string, n)
+	for i := 0; i < n; i++ {
+		q := fmt.Sprintf("SELECT %d", i+1)
+		go func(query string) {
+			defer wg.Done()
+			res := m.EksekusiQuery(query)
+			resCh <- res
+		}(q)
+	}
+	wg.Wait()
+	close(resCh)
+	out := make([]string, 0, n)
+	for s := range resCh {
+		out = append(out, s)
+	}
+	return out
+}