Activate Stmt cache by default.

README

@@ -6,6 +6,7 @@ This binding implements the "database/sql/driver" interface.
 Open supports flags.
 Conn#Exec handles multiple statements (separated by semicolons) properly.
 Conn#Prepare can optionnaly #Bind as well.
+Conn#CacheOrPrepare can reused already prepared Stmt.
 Conn#Close ensures that all dangling statements are finalized.
 Stmt#Exec is renamed in Stmt#Bind and a new Stmt#Exec method is introduced to #Bind and #Step.
 Stmt#Bind uses native sqlite3_bind_x methods and failed if unsupported type.
@@ -82,10 +83,15 @@ Conn#CreateAggregateFunction
 
 $ go test -test.bench '.*'
 BenchmarkValuesScan 500000  4658 ns/op
-BenchmarkScan	  	  500000	      4324 ns/op
+BenchmarkScan       500000   324 ns/op
 BenchmarkNamedScan  200000  9221 ns/op
+
 BenchmarkInsert       500000  6088 ns/op
 BenchmarkNamedInsert  500000  6726 ns/op
+
+BenchmarkDisabledCache   100000  19235 ns/op
+BenchmarkEnabledCache   1000000   1133 ns/op
+
 BenchmarkLike   1000000  2508 ns/op
 BenchmarkHalf    500000  4811 ns/op
 BenchmarkRegexp  500000  6170 ns/op
\ No newline at end of file

cache.go

@@ -11,7 +11,7 @@ import (
 )
 
 const (
-	defaultCacheSize = 0
+	defaultCacheSize = 10
 )
 
 // Like http://www.sqlite.org/tclsqlite.html#cache

driver.go

@@ -56,7 +56,7 @@ func (c *connImpl) RowsAffected() (int64, error) {
 }
 
 func (c *connImpl) Prepare(query string) (driver.Stmt, error) {
-	s, err := c.c.Prepare(query)
+	s, err := c.c.CacheOrPrepare(query)
 	if err != nil {
 		return nil, err
 	}

sqlite.go

@@ -345,22 +345,28 @@ func (c *Conn) Exec(cmd string, args ...interface{}) error {
 
 // Return true if the specified query returns at least one row.
 func (c *Conn) Exists(query string, args ...interface{}) (bool, error) {
-	s, err := c.Prepare(query, args...)
+	s, err := c.CacheOrPrepare(query, args...)
 	if err != nil {
 		return false, err
 	}
-	defer s.finalize()
+	defer func() {
+		s.Reset()
+		s.Finalize()
+	}()
 	return s.Next()
 }
 
 // Use it with SELECT that returns only one row with only one column.
 // Returns io.EOF when there is no row.
 func (c *Conn) OneValue(query string, value interface{}, args ...interface{}) error {
-	s, err := c.Prepare(query, args...)
+	s, err := c.CacheOrPrepare(query, args...)
 	if err != nil {
 		return err
 	}
-	defer s.finalize()
+	defer func() {
+		s.Reset()
+		s.Finalize()
+	}()
 	b, err := s.Next()
 	if err != nil {
 		return err