Connection Pooling Enhancement to create connection in advance

vmathur12 · Oct 14, 2022 · 254b1b5 · 254b1b5
2 parents cd4d1b0 + f6595c3
commit 254b1b5
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diff --git a/API_DOCUMENTATION.md b/API_DOCUMENTATION.md
@@ -21,6 +21,8 @@
 10.	[.Columns()](#ColumnsApi)
 11.	[.Next()](#NextApi)
 12.	[.Scan(options)](#ScanApi)
+13.	[.Init(N,connStr)](#InitApi)
+14.	[.SetConnMaxLifetime(N)](#SetConnMaxLifetimeApi)
 
 ### <a name="OpenApi"></a> 1) .Open(drivername,ConnectionString)
 
@@ -350,6 +352,76 @@ func oper() error {
 }
 ```
 
+### <a name="InitApi"></a> 13) .Init(N,connStr)
+
+Initialize Pool with N no of active connections using supplied connection string. It is a synchronous API. We do not need an asynchronous version of this API.
+* **N** - No of connections to be initialized.
+* **connStr** - The connection string for your database
+```go
+func oper() error {
+        fmt.Println("connecting to database")
+
+	var ret = pool.init(5, connStr)
+	if ret != true {
+		fmt.Println(ret)
+	}
+
+        db := pool.Open(connStr, "SetConnMaxLifetime=10")
+	for i:=0; i<20; i++ {
+		db := pool.Open(con, "SetConnMaxLifetime=10")
+                if db != nil {
+                        st, err := db.Prepare("select * from SAMPLE")
+                        if err != nil {
+                                fmt.Println("Error: ", err)
+                        } else {
+                                go func() {
+                                        ExecQuery(st)
+                                        db.Close()
+                                }()
+                        }
+                }
+        }
+
+        time.Sleep(30*time.Second)
+        pool.Release()
+        return nil
+}
+func ExecQuery(st *sql.Stmt) error {
+        res, err := st5.Query()
+        if err != nil {
+             fmt.Println(err)
+        }
+        cols, _ := res.Columns()
+
+        fmt.Printf("%s    %s   %s     %s\n", cols[0], cols[1], cols[2], cols[3])
+        defer res.Close()
+        for res.Next() {
+                    var t, x, m, n string
+                    err = res.Scan(&t, &x, &m, &n)
+                    fmt.Printf("%v  %v   %v  %v\n", t, x, m, n)
+        }
+        return nil
+}
+```
+
+### <a name="SetConnMaxLifetime"></a> 14) .SetConnMaxLifetime(T)
+
+Set the maximum length of time a connection can held open before it is closed.
+* **T** - Maximum lenght of time the connection can held open.
+
+```go
+func oper() error {
+        fmt.Println("connecting to database")a
+
+  	pool.SetConnMaxLifetime(10)
+        ret := pool.Init(3, con)
+        if ret != true {
+		fmt.Println(ret)
+        }
+        return nil
+}
+```
+
 ## Create and Drop Database APIs
 
 ### <a name="CreateDb"></a> .CreateDb(dbName, connectionString, options...)

diff --git a/README.md b/README.md
@@ -286,6 +286,64 @@ func main() {
 ```
 To run the sample:- go run example3.go
 
+### example4.go:-(POOLING- Limit on the number of connetions)
+
+```go
+package main
+
+import (
+           "database/sql"
+           "fmt"
+           "time"
+          a "github.com/ibmdb/go_ibm_db"
+       )
+
+func ExecQuery(st *sql.Stmt) error {
+        res, err := st.Query()
+        if err != nil {
+             fmt.Println(err)
+        }
+        cols, _ := res.Columns()
+
+        fmt.Printf("%s    %s   %s     %s\n", cols[0], cols[1], cols[2], cols[3])
+        defer res.Close()
+        for res.Next() {
+                    var t, x, m, n string
+                    err = res.Scan(&t, &x, &m, &n)
+                    fmt.Printf("%v  %v   %v     %v\n", t, x, m, n)
+        }
+        return nil
+}
+
+func main() {
+	con := "HOSTNAME=host;PORT=number;DATABASE=name;UID=username;PWD=password"
+        pool := a.Pconnect("PoolSize=5")
+
+        ret := pool.Init(5, con)
+        if ret != true {
+                fmt.Println("Pool initializtion failed")
+        }
+
+        for i:=0; i<20; i++ {
+                db1 := pool.Open(con, "SetConnMaxLifetime=10")
+                if db1 != nil {
+                        st1, err1 := db1.Prepare("select * from VMSAMPLE")
+                        if err1 != nil {
+                                fmt.Println("err1 : ", err1)
+                        }else{
+                                go func() {
+                                        execquery(st1)
+                                        db1.Close()
+                                }()
+                        }
+                }
+        }
+        time.Sleep(30*time.Second)
+        pool.Release()
+}
+```
+To run the sample:- go run example4.go
+
 For Running the Tests:
 ======================