caching session bounded sql.Stmt to increase performance

session.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"hash/crc32"
 	"reflect"
 	"strconv"
 	"strings"
@@ -33,6 +34,8 @@ type Session struct {
 
 	beforeClosures []func(interface{})
 	afterClosures  []func(interface{})
+
+	stmtCache map[uint32]*sql.Stmt //key: hash.Hash32 of (queryStr, len(queryStr))
 }
 
 // Method Init reset the session as the init status.
@@ -53,14 +56,17 @@ func (session *Session) Init() {
 
 // Method Close release the connection from pool
 func (session *Session) Close() {
-	defer func() {
-		if session.Db != nil {
-			session.Engine.Pool.ReleaseDB(session.Engine, session.Db)
-			session.Db = nil
-			session.Tx = nil
-			session.Init()
-		}
-	}()
+	for _, v := range session.stmtCache {
+		v.Close()
+	}
+
+	if session.Db != nil {
+		session.Engine.Pool.ReleaseDB(session.Engine, session.Db)
+		session.Db = nil
+		session.Tx = nil
+		session.stmtCache = nil
+		session.Init()
+	}
 }
 
 // Method Sql provides raw sql input parameter. When you have a complex SQL statement
@@ -256,6 +262,7 @@ func (session *Session) newDb() error {
 			return err
 		}
 		session.Db = db
+		session.stmtCache = make(map[uint32]*sql.Stmt, 0)
 	}
 	return nil
 }
@@ -394,13 +401,13 @@ func (session *Session) scanMapIntoStruct(obj interface{}, objMap map[string][]b
 
 //Execute sql
 func (session *Session) innerExec(sqlStr string, args ...interface{}) (sql.Result, error) {
-	rs, err := session.Db.Prepare(sqlStr)
+	stmt, err := session.doPrepare(sqlStr)
 	if err != nil {
 		return nil, err
 	}
-	defer rs.Close()
+	//defer stmt.Close()
 
-	res, err := rs.Exec(args...)
+	res, err := stmt.Exec(args...)
 	if err != nil {
 		return nil, err
 	}
@@ -866,6 +873,21 @@ func (session *Session) Iterate(bean interface{}, fun IterFunc) error {
 	return nil
 }
 
+func (session *Session) doPrepare(sqlStr string) (stmt *sql.Stmt, err error) {
+	crc := crc32.ChecksumIEEE([]byte(sqlStr))
+	// TODO try hash(sqlStr+len(sqlStr))
+	var has bool
+	stmt, has = session.stmtCache[crc]
+	if !has {
+		stmt, err = session.Db.Prepare(sqlStr)
+		if err != nil {
+			return nil, err
+		}
+		session.stmtCache[crc] = stmt
+	}
+	return
+}
+
 // get retrieve one record from database, bean's non-empty fields
 // will be as conditions
 func (session *Session) Get(bean interface{}) (bool, error) {
@@ -901,11 +923,11 @@ func (session *Session) Get(bean interface{}) (bool, error) {
 	var rawRows *sql.Rows
 	session.queryPreprocess(&sqlStr, args...)
 	if session.IsAutoCommit {
-		stmt, err := session.Db.Prepare(sqlStr)
+		stmt, err := session.doPrepare(sqlStr)
 		if err != nil {
 			return false, err
 		}
-		defer stmt.Close()
+		// defer stmt.Close() // !nashtsai! don't close due to stmt is cached and bounded to this session
 		rawRows, err = stmt.Query(args...)
 	} else {
 		rawRows, err = session.Tx.Query(sqlStr, args...)
@@ -1070,11 +1092,10 @@ func (session *Session) Find(rowsSlicePtr interface{}, condiBean ...interface{})
 		// defer rawRows.Close()
 
 		if session.IsAutoCommit {
-			stmt, err = session.Db.Prepare(sqlStr)
+			stmt, err = session.doPrepare(sqlStr)
 			if err != nil {
 				return err
 			}
-			defer stmt.Close()
 			rawRows, err = stmt.Query(args...)
 		} else {
 			rawRows, err = session.Tx.Query(sqlStr, args...)
@@ -1165,19 +1186,19 @@ func (session *Session) Find(rowsSlicePtr interface{}, condiBean ...interface{})
 	return nil
 }
 
-func (session *Session) queryRows(rawStmt **sql.Stmt, rawRows **sql.Rows, sqlStr string, args ...interface{}) error {
-	var err error
-	if session.IsAutoCommit {
-		*rawStmt, err = session.Db.Prepare(sqlStr)
-		if err != nil {
-			return err
-		}
-		*rawRows, err = (*rawStmt).Query(args...)
-	} else {
-		*rawRows, err = session.Tx.Query(sqlStr, args...)
-	}
-	return err
-}
+// func (session *Session) queryRows(rawStmt **sql.Stmt, rawRows **sql.Rows, sqlStr string, args ...interface{}) error {
+// 	var err error
+// 	if session.IsAutoCommit {
+// 		*rawStmt, err = session.doPrepare(sqlStr)
+// 		if err != nil {
+// 			return err
+// 		}
+// 		*rawRows, err = (*rawStmt).Query(args...)
+// 	} else {
+// 		*rawRows, err = session.Tx.Query(sqlStr, args...)
+// 	}
+// 	return err
+// }
 
 // Test if database is ok
 func (session *Session) Ping() error {