Refactor and tune Explain table display

Author: blacktear23

kvcmds/cmd_explain.go

@@ -62,7 +62,7 @@ func (c ExplainCmd) Handler() func(ctx context.Context) {
 				}
 				ret = append(ret, []string{planStr})
 			}
-			utils.PrintTable(ret)
+			utils.PrintTableNoWrap(ret)
 			return nil
 		})
 	}

query/filter_optimizer.go

@@ -26,7 +26,7 @@ type ScanType struct {
 type FilterOptimizer struct {
 	expr   Expression
 	filter *FilterExec
-	txn    *Txn
+	txn    Txn
 }
 
 func (st *ScanType) String() string {
@@ -58,7 +58,7 @@ func ScanTypeToString(tp byte) string {
 	return "UNKNOWN"
 }
 
-func NewFilterOptimizer(ast *WhereStmt, t *Txn, filter *FilterExec) *FilterOptimizer {
+func NewFilterOptimizer(ast *WhereStmt, t Txn, filter *FilterExec) *FilterOptimizer {
 	return &FilterOptimizer{
 		expr:   ast.Expr,
 		txn:    t,

query/kv.go

@@ -0,0 +1,11 @@
+package query
+
+type Txn interface {
+	Get(key []byte) (value []byte, err error)
+	Cursor() (cursor Cursor, err error)
+}
+
+type Cursor interface {
+	Seek(prefix []byte) error
+	Next() (key []byte, value []byte, err error)
+}

query/optimizer.go

@@ -25,7 +25,7 @@ func (o *Optimizer) init() error {
 	return nil
 }
 
-func (o *Optimizer) BuildPlan(t *Txn) (*ProjectionPlan, error) {
+func (o *Optimizer) BuildPlan(t Txn) (*ProjectionPlan, error) {
 	err := o.init()
 	if err != nil {
 		return nil, err
@@ -71,7 +71,7 @@ func (o *Optimizer) BuildPlan(t *Txn) (*ProjectionPlan, error) {
 	}, nil
 }
 
-func (o *Optimizer) buildLimitPlan(t *Txn, fp Plan) Plan {
+func (o *Optimizer) buildLimitPlan(t Txn, fp Plan) Plan {
 	return &LimitPlan{
 		Txn:       t,
 		Start:     o.stmt.Limit.Start,
@@ -80,7 +80,7 @@ func (o *Optimizer) buildLimitPlan(t *Txn, fp Plan) Plan {
 	}
 }
 
-func (o *Optimizer) buildOrderPlan(t *Txn, fp Plan) Plan {
+func (o *Optimizer) buildOrderPlan(t Txn, fp Plan) Plan {
 	if len(o.stmt.Order.Orders) == 1 {
 		order := o.stmt.Order.Orders[0]
 		switch expr := order.Field.(type) {
@@ -98,7 +98,7 @@ func (o *Optimizer) buildOrderPlan(t *Txn, fp Plan) Plan {
 	}
 }
 
-func (o *Optimizer) buildScanPlan(t *Txn) Plan {
+func (o *Optimizer) buildScanPlan(t Txn) Plan {
 	fopt := NewFilterOptimizer(o.filter.Ast, t, o.filter)
 	return fopt.Optimize()
 }

query/plan.go

@@ -29,12 +29,12 @@ var (
 type Column []byte
 
 type FullScanPlan struct {
-	Txn    *Txn
+	Txn    Txn
 	Filter *FilterExec
-	iter   *Cursor
+	iter   Cursor
 }
 
-func NewFullScanPlan(t *Txn, f *FilterExec) Plan {
+func NewFullScanPlan(t Txn, f *FilterExec) Plan {
 	return &FullScanPlan{
 		Txn:    t,
 		Filter: f,
@@ -78,10 +78,10 @@ func (p *FullScanPlan) Next() ([]byte, []byte, error) {
 }
 
 type EmptyResultPlan struct {
-	Txn *Txn
+	Txn Txn
 }
 
-func NewEmptyResultPlan(t *Txn, f *FilterExec) Plan {
+func NewEmptyResultPlan(t Txn, f *FilterExec) Plan {
 	return &EmptyResultPlan{
 		Txn: t,
 	}
@@ -104,13 +104,13 @@ func (p *EmptyResultPlan) Explain() []string {
 }
 
 type PrefixScanPlan struct {
-	Txn    *Txn
+	Txn    Txn
 	Filter *FilterExec
 	Prefix string
-	iter   *Cursor
+	iter   Cursor
 }
 
-func NewPrefixScanPlan(t *Txn, f *FilterExec, p string) Plan {
+func NewPrefixScanPlan(t Txn, f *FilterExec, p string) Plan {
 	return &PrefixScanPlan{
 		Txn:    t,
 		Filter: f,
@@ -163,14 +163,14 @@ func (p *PrefixScanPlan) Explain() []string {
 }
 
 type MultiGetPlan struct {
-	Txn     *Txn
+	Txn     Txn
 	Filter  *FilterExec
 	Keys    []string
 	numKeys int
 	idx     int
 }
 
-func NewMultiGetPlan(t *Txn, f *FilterExec, keys []string) Plan {
+func NewMultiGetPlan(t Txn, f *FilterExec, keys []string) Plan {
 	// We should sort keys to ensure order by erase works correctly
 	sort.Strings(keys)
 	return &MultiGetPlan{
@@ -222,7 +222,7 @@ func (p *MultiGetPlan) Explain() []string {
 }
 
 type LimitPlan struct {
-	Txn       *Txn
+	Txn       Txn
 	Start     int
 	Count     int
 	current   int
@@ -276,7 +276,7 @@ func (p *LimitPlan) Explain() []string {
 }
 
 type ProjectionPlan struct {
-	Txn       *Txn
+	Txn       Txn
 	ChildPlan Plan
 	AllFields bool
 	Fields    []Expression
@@ -502,7 +502,7 @@ func (h orderRowHeap) Less(i, j int) bool {
 }
 
 type OrderPlan struct {
-	Txn       *Txn
+	Txn       Txn
 	Orders    []OrderField
 	ChildPlan Plan
 	pos       int
@@ -577,14 +577,14 @@ func (p *OrderPlan) Explain() []string {
 }
 
 type RangeScanPlan struct {
-	Txn    *Txn
+	Txn    Txn
 	Filter *FilterExec
 	Start  []byte
 	End    []byte
-	iter   *Cursor
+	iter   Cursor
 }
 
-func NewRangeScanPlan(t *Txn, f *FilterExec, start []byte, end []byte) Plan {
+func NewRangeScanPlan(t Txn, f *FilterExec, start []byte, end []byte) Plan {
 	return &RangeScanPlan{
 		Txn:    t,
 		Filter: f,

query/query_txn.go

@@ -10,43 +10,48 @@ import (
 	"github.com/magiconair/properties"
 )
 
-type Txn struct {
+var (
+	_ Txn    = (*queryTxn)(nil)
+	_ Cursor = (*queryCursor)(nil)
+)
+
+type queryTxn struct {
 	client client.Client
 }
 
-func NewQueryTxn(client client.Client) *Txn {
-	return &Txn{
+func NewQueryTxn(client client.Client) Txn {
+	return &queryTxn{
 		client: client,
 	}
 }
 
-func (t *Txn) Get(key []byte) ([]byte, error) {
+func (t *queryTxn) Get(key []byte) ([]byte, error) {
 	kv, err := t.client.Get(context.TODO(), client.Key(key))
 	if err != nil {
 		return nil, err
 	}
 	return kv.V, nil
 }
 
-func (t *Txn) Cursor() (*Cursor, error) {
-	return &Cursor{
+func (t *queryTxn) Cursor() (Cursor, error) {
+	return &queryCursor{
 		txn:     t,
 		batch:   nil,
 		prefix:  []byte{},
 		iterPos: 0,
 	}, nil
 }
 
-type Cursor struct {
-	txn         *Txn
+type queryCursor struct {
+	txn         *queryTxn
 	batch       client.KVS
 	batchSize   int
 	prefix      []byte
 	iterPos     int
 	prevLastKey []byte
 }
 
-func (c *Cursor) loadBatch() error {
+func (c *queryCursor) loadBatch() error {
 	scanOpt := properties.NewProperties()
 	scanOpt.Set(tcli.ScanOptLimit, "10")
 	scanOpt.Set(tcli.ScanOptKeyOnly, "false")
@@ -61,6 +66,7 @@ func (c *Cursor) loadBatch() error {
 	c.batchSize = n
 	c.iterPos = 0
 	if len(kvs) > 0 {
+		// Skip first key
 		if c.prevLastKey != nil && bytes.Compare(kvs[0].K, c.prevLastKey) == 0 {
 			c.batch = c.batch[1:]
 			c.batchSize--
@@ -71,7 +77,7 @@ func (c *Cursor) loadBatch() error {
 	return nil
 }
 
-func (c *Cursor) Next() (key []byte, val []byte, err error) {
+func (c *queryCursor) Next() (key []byte, val []byte, err error) {
 	if c.batch == nil || c.iterPos >= c.batchSize {
 		err = c.loadBatch()
 		if err != nil {
@@ -88,7 +94,7 @@ func (c *Cursor) Next() (key []byte, val []byte, err error) {
 	return key, val, nil
 }
 
-func (c *Cursor) Seek(key []byte) error {
+func (c *queryCursor) Seek(key []byte) error {
 	c.prefix = key
 	c.batch = nil
 	c.batchSize = 0

utils/utils.go

@@ -31,6 +31,16 @@ func PrintTable(data [][]string) {
 	table.Render()
 }
 
+func PrintTableNoWrap(data [][]string) {
+	table := tablewriter.NewWriter(os.Stdout)
+	table.SetHeader(data[0])
+	table.SetAutoWrapText(false)
+	table.SetBorders(tablewriter.Border{Left: true, Top: true, Right: true, Bottom: true})
+	table.SetCenterSeparator("|")
+	table.AppendBulk(data[1:])
+	table.Render()
+}
+
 func OutputWithElapse(f func() error) error {
 	tt := time.Now()
 	err := f()