Store fields counts in struct mapping and initialize slices capacity …

…to improve performances.

.gitignore

@@ -2,6 +2,9 @@
 *.swp
 .vscode
 
+# Profiling
+*.out
+
 # Databases
 *.db
 

dbreflect/dbreflect.go

@@ -19,6 +19,9 @@ type StructMapping struct {
 	Name          string
 	structMapping structMappingDetails
 	opLockSQLName string
+	fieldCount    int
+	keyCount      int
+	autoCount     int
 }
 
 // innerStructMapping contains the details of a relation between a struct
@@ -58,6 +61,7 @@ func NewStructMapping(structInfo reflect.Type) (*StructMapping, error) {
 	}
 
 	sm.Name = sm.structMapping.name
+	sm.setFieldsCount()
 
 	err = sm.setOpLockField()
 	if err != nil {
@@ -160,7 +164,7 @@ func (smd *structMappingDetails) newSubStructMapping(structField reflect.StructF
 	// Optional prefix and relation
 	var options map[string]string
 	subStructMapping.prefix, options = smd.tagData(structField.Tag)
-	if relation,ok := options[optionRelation]; ok {
+	if relation, ok := options[optionRelation]; ok {
 		subStructMapping.relation = relation
 	}
 
@@ -194,6 +198,26 @@ func (*structMappingDetails) tagData(tag reflect.StructTag) (string, map[string]
 	return firstValue, tagMaps
 }
 
+// setFieldsCount set all fields count (all, auto, keys)
+func (sm *StructMapping) setFieldsCount() {
+	sm.fieldCount = 0
+	sm.autoCount = 0
+	sm.keyCount = 0
+
+	f := func(_ string, fieldMapping *fieldMapping, _ *reflect.Value) (stop bool, err error) {
+		sm.fieldCount++
+		if fieldMapping.isAuto {
+			sm.autoCount++
+		}
+		if fieldMapping.isKey {
+			sm.keyCount++
+		}
+		return false, nil
+	}
+
+	sm.structMapping.traverseTree("", "", nil, f)
+}
+
 // setOpLockField searchs optimistic locking field an update the struct mapping
 // with the op lock field data.
 // It returns an error if there is more then one op lock field.
@@ -242,7 +266,7 @@ func isValidNonAutoOpLockFieldType(fieldMapping *fieldMapping) bool {
 
 // GetAllColumnsNames returns the names of all columns.
 func (sm *StructMapping) GetAllColumnsNames() []string {
-	columns := make([]string, 0, 0)
+	columns := make([]string, 0, sm.fieldCount)
 
 	f := func(fullName string, _ *fieldMapping, _ *reflect.Value) (stop bool, err error) {
 		columns = append(columns, fullName)
@@ -255,7 +279,7 @@ func (sm *StructMapping) GetAllColumnsNames() []string {
 
 // GetNonAutoColumnsNames returns the names of non auto columns.
 func (sm *StructMapping) GetNonAutoColumnsNames() []string {
-	columns := make([]string, 0, 0)
+	columns := make([]string, 0, sm.fieldCount-sm.autoCount)
 
 	f := func(fullName string, fieldMapping *fieldMapping, _ *reflect.Value) (stop bool, err error) {
 		if !fieldMapping.isAuto {
@@ -270,7 +294,7 @@ func (sm *StructMapping) GetNonAutoColumnsNames() []string {
 
 // GetAutoColumnsNames returns the names of auto columns.
 func (sm *StructMapping) GetAutoColumnsNames() []string {
-	columns := make([]string, 0, 0)
+	columns := make([]string, 0, sm.autoCount)
 
 	f := func(fullName string, fieldMapping *fieldMapping, _ *reflect.Value) (stop bool, err error) {
 		if fieldMapping.isAuto {
@@ -285,7 +309,7 @@ func (sm *StructMapping) GetAutoColumnsNames() []string {
 
 // GetKeyColumnsNames returns the names of key columns.
 func (sm *StructMapping) GetKeyColumnsNames() []string {
-	columns := make([]string, 0, 0)
+	columns := make([]string, 0, sm.keyCount)
 
 	f := func(fullName string, fieldMapping *fieldMapping, _ *reflect.Value) (stop bool, err error) {
 		if fieldMapping.isKey {
@@ -305,7 +329,7 @@ func (sm *StructMapping) GetAllFieldsPointers(s interface{}) []interface{} {
 	v := reflect.ValueOf(s)
 	v = reflect.Indirect(v)
 
-	pointers := make([]interface{}, 0, 0)
+	pointers := make([]interface{}, 0, sm.fieldCount)
 
 	f := func(fullName string, _ *fieldMapping, value *reflect.Value) (stop bool, err error) {
 		pointers = append(pointers, value.Addr().Interface())
@@ -323,7 +347,7 @@ func (sm *StructMapping) GetNonAutoFieldsValues(s interface{}) []interface{} {
 	v := reflect.ValueOf(s)
 	v = reflect.Indirect(v)
 
-	values := make([]interface{}, 0, 0)
+	values := make([]interface{}, 0, sm.fieldCount-sm.autoCount)
 
 	f := func(fullName string, fieldMapping *fieldMapping, value *reflect.Value) (stop bool, err error) {
 		if !fieldMapping.isAuto {
@@ -343,7 +367,7 @@ func (sm *StructMapping) GetKeyFieldsValues(s interface{}) []interface{} {
 	v := reflect.ValueOf(s)
 	v = reflect.Indirect(v)
 
-	values := make([]interface{}, 0, 0)
+	values := make([]interface{}, 0, sm.keyCount)
 
 	f := func(fullName string, fieldMapping *fieldMapping, value *reflect.Value) (stop bool, err error) {
 		if fieldMapping.isKey {
@@ -423,7 +447,7 @@ func (sm *StructMapping) GetAutoFieldsPointers(s interface{}) ([]interface{}, er
 	v := reflect.ValueOf(s)
 	v = reflect.Indirect(v)
 
-	pointers := make([]interface{}, 0, 0)
+	pointers := make([]interface{}, 0, sm.autoCount)
 
 	f := func(fullName string, fieldMapping *fieldMapping, value *reflect.Value) (stop bool, err error) {
 		if fieldMapping.isAuto {
@@ -510,7 +534,7 @@ func (smd *structMappingDetails) traverseTree(relation string, prefix string, st
 		if relation != "" {
 			fullName = relation + "." + fullName
 		}
-		
+
 		if startValue != nil {
 			fieldValue := startValue.FieldByName(fm.name)
 			stopped, err = f(fullName, &fm, &fieldValue)

dbreflect/dbreflect_bench_test.go

@@ -5,6 +5,7 @@ import (
 	"testing"
 )
 
+// Record will be used to bench dbreflect (no meaning by itself)
 type Record struct {
 	ID     int    `db:"id,key,auto"`
 	Dummy1 string `db:"dummy1"`
@@ -14,14 +15,25 @@ type Record struct {
 	Dummy5 string `db:"dummy5"`
 }
 
-// go test -bench=GetAllFieldsPointers -run=none ./dbreflect/ -benchtime=10s -cpuprofile cpu.out
-// $GOPATH/bin/pprof -http=localhost:7777 cpu.out
-
-// go test -bench=GetAllFieldsPointers -run=nore ./dbreflect/ -benchtime=10s -benchmem -memprofilerate=1 -memprofile mem.out
-// $GOPATH/bin/pprof -http=localhost:7777 -alloc_space mem.out
-
-// Escape analysis : go test -gcglags "-m"... (ou go build)
-// gcglags informations : go tool compile -help
+// Tips to benchmark :
+//
+// Do a simple bencmark, without profiling :
+//   go test -bench=GetAllFieldsPointers -run=^$ ./dbreflect/ -benchmem -benchtime=10s
+//
+// CPU profiling, and analysis using a browser :
+//   go test -bench=GetAllFieldsPointers -run=^$ ./dbreflect/ -benchtime=10s -cpuprofile cpu.out
+//   $GOPATH/bin/pprof -http=localhost:7777 cpu.out
+//
+// Memory profiling, and analysis using a browser :
+//   go test -bench=GetAllFieldsPointers -run=^$ ./dbreflect/ -benchtime=10s -benchmem -memprofilerate=1 -memprofile mem.out
+//   $GOPATH/bin/pprof -http=localhost:7777 -alloc_space mem.out
+//
+// Escape analysis : go test -gcflags="-m -m"...
+//   go test -gcflags="-m -m" ./dbreflect 2>&1 | grep dbreflect.go
+//
+// Note : profiling is done here with latest pprof.
+// Install it with :
+//   go get -u github.com/google/pprof
 
 func BenchmarkGetAllFieldsPointers(b *testing.B) {
 	r := Record{}

dbreflect/dbreflect_test.go

@@ -64,7 +64,7 @@ type ComplexStructsWithRelations struct {
 	// no prefix but a relation
 	SimpleStruct `db:",rel=firsttable"`
 	// prefix and relation
-	Foobar SubStruct `db:"nested_,rel=secondtable"`		
+	Foobar SubStruct `db:"nested_,rel=secondtable"`
 }
 
 func TestStructMapping(t *testing.T) {
@@ -75,11 +75,17 @@ func TestStructMapping(t *testing.T) {
 			So(structMap.Name, ShouldEndWith, "SimpleStruct")
 		})
 
-		Convey("It store data about all tagged fields ", func() {
+		Convey("It store data about all tagged fields", func() {
 			So(len(structMap.GetAllColumnsNames()), ShouldEqual, 2)
 			So(structMap.GetAllColumnsNames(), ShouldContain, "id")
 			So(structMap.GetAllColumnsNames(), ShouldContain, "my_text")
 		})
+
+		Convey("It counts fields", func() {
+			So(structMap.fieldCount, ShouldEqual, 2)
+			So(structMap.autoCount, ShouldEqual, 1)
+			So(structMap.keyCount, ShouldEqual, 1)
+		})
 	})
 
 	Convey("NewStructMapping with a complex struct type with sub-structs", t, func() {
@@ -96,6 +102,12 @@ func TestStructMapping(t *testing.T) {
 			So(structMapDetails.subStructMapping[1].prefix, ShouldEqual, "nested_")
 			So(structMapDetails.subStructMapping[1].structMapping.name, ShouldEndWith, "SubStruct")
 		})
+
+		Convey("It counts fields", func() {
+			So(structMap.fieldCount, ShouldEqual, 5)
+			So(structMap.autoCount, ShouldEqual, 1)
+			So(structMap.keyCount, ShouldEqual, 1)
+		})
 	})
 
 	Convey("NewStructMapping with nested structs and relations", t, func() {
@@ -112,7 +124,7 @@ func TestStructMapping(t *testing.T) {
 			So(structMapDetails.subStructMapping[1].prefix, ShouldEqual, "nested_")
 			So(structMapDetails.subStructMapping[1].relation, ShouldEndWith, "secondtable")
 		})
-	})	
+	})
 }
 
 func TestScannableStructs(t *testing.T) {
@@ -178,7 +190,7 @@ func TestGetAllColumnsNames(t *testing.T) {
 			So(columns[2], ShouldEqual, "secondtable.nested_foo")
 			So(columns[3], ShouldEqual, "secondtable.nested_bar")
 		})
-	})	
+	})
 }
 
 func TestGetNonAutoColumnsNames(t *testing.T) {