Add object pooling for parser expressions

psql/bench.5

@@ -0,0 +1,7 @@
+goos: darwin
+goarch: amd64
+pkg: github.com/dosco/super-graph/psql
+BenchmarkCompile-8           	  100000	     15728 ns/op	    3000 B/op	      60 allocs/op
+BenchmarkCompileParallel-8   	  300000	      5077 ns/op	    3023 B/op	      60 allocs/op
+PASS
+ok  	github.com/dosco/super-graph/psql	3.318s

psql/psql.go

@@ -657,10 +657,12 @@ func (c *compilerContext) renderWhere(sel *qcode.Select, ti *DBTableInfo) error
 						st.Push(val.Op)
 					}
 				}
+				qcode.FreeExp(val)
 				continue
 			case qcode.OpNot:
 				st.Push(val.Children[0])
 				st.Push(qcode.OpNot)
+				qcode.FreeExp(val)
 				continue
 			}
 
@@ -669,6 +671,7 @@ func (c *compilerContext) renderWhere(sel *qcode.Select, ti *DBTableInfo) error
 				c.w.WriteString(`(("`)
 				c.w.WriteString(val.Col)
 				c.w.WriteString(`") `)
+
 			} else if len(val.Col) != 0 {
 				//fmt.Fprintf(w, `(("%s"."%s") `, c.sel.Table, val.Col)
 				c.w.WriteString(`((`)
@@ -757,9 +760,12 @@ func (c *compilerContext) renderWhere(sel *qcode.Select, ti *DBTableInfo) error
 				c.w.WriteString(`)`)
 			}
 
+			qcode.FreeExp(val)
+
 		default:
 			return fmt.Errorf("12: unexpected value %v (%t)", intf, intf)
 		}
+
 	}
 
 	return nil

qcode/parse.go

@@ -523,6 +523,6 @@ func (t parserType) String() string {
 	return fmt.Sprintf("<%s>", v)
 }
 
-func PutNode(n *Node) {
+func FreeNode(n *Node) {
 	nodePool.Put(n)
 }

qcode/qcode.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"strings"
+	"sync"
 
 	"github.com/dosco/super-graph/util"
 	"github.com/gobuffalo/flect"
@@ -51,6 +52,13 @@ type Exp struct {
 	ListVal   []string
 	Children  []*Exp
 	childrenA [5]*Exp
+	doFree    bool
+}
+
+var zeroExp = Exp{doFree: true}
+
+func (ex *Exp) Reset() {
+	*ex = zeroExp
 }
 
 type OrderBy struct {
@@ -141,6 +149,10 @@ type Compiler struct {
 	ka bool
 }
 
+var expPool = sync.Pool{
+	New: func() interface{} { return new(Exp) },
+}
+
 func NewCompiler(c Config) (*Compiler, error) {
 	bl := make(map[string]struct{}, len(c.Blacklist))
 
@@ -385,10 +397,10 @@ func (com *Compiler) compileArgObj(arg *Arg) (*Exp, error) {
 		return nil, fmt.Errorf("expecting an object")
 	}
 
-	return com.compileArgNode(arg.Val)
+	return com.compileArgNode(arg.Val, true)
 }
 
-func (com *Compiler) compileArgNode(node *Node) (*Exp, error) {
+func (com *Compiler) compileArgNode(node *Node, usePool bool) (*Exp, error) {
 	st := util.NewStack()
 	var root *Exp
 
@@ -415,8 +427,7 @@ func (com *Compiler) compileArgNode(node *Node) (*Exp, error) {
 			}
 		}
 
-		ex, err := newExp(st, eT)
-
+		ex, err := newExp(st, eT, usePool)
 		if err != nil {
 			return nil, err
 		}
@@ -459,7 +470,11 @@ func (com *Compiler) compileArgID(sel *Select, arg *Arg) error {
 		return nil
 	}
 
-	ex := &Exp{Op: OpEqID, Val: arg.Val.Val}
+	ex := expPool.Get().(*Exp)
+	ex.Reset()
+
+	ex.Op = OpEqID
+	ex.Val = arg.Val.Val
 
 	switch arg.Val.Type {
 	case nodeStr:
@@ -479,11 +494,12 @@ func (com *Compiler) compileArgID(sel *Select, arg *Arg) error {
 }
 
 func (com *Compiler) compileArgSearch(sel *Select, arg *Arg) error {
-	ex := &Exp{
-		Op:   OpTsQuery,
-		Type: ValStr,
-		Val:  arg.Val.Val,
-	}
+	ex := expPool.Get().(*Exp)
+	ex.Reset()
+
+	ex.Op = OpTsQuery
+	ex.Type = ValStr
+	ex.Val = arg.Val.Val
 
 	if sel.Where != nil {
 		ow := sel.Where
@@ -643,7 +659,7 @@ func compileSub() (*Query, error) {
 	return nil, nil
 }
 
-func newExp(st *util.Stack, eT *expT) (*Exp, error) {
+func newExp(st *util.Stack, eT *expT, usePool bool) (*Exp, error) {
 	node := eT.node
 
 	if len(node.Name) == 0 {
@@ -656,7 +672,15 @@ func newExp(st *util.Stack, eT *expT) (*Exp, error) {
 		name = name[1:]
 	}
 
-	ex := &Exp{}
+	var ex *Exp
+
+	if usePool {
+		ex = expPool.Get().(*Exp)
+		ex.Reset()
+	} else {
+		ex = &Exp{}
+	}
+	ex.Children = ex.childrenA[:0]
 
 	switch name {
 	case "and":
@@ -831,7 +855,7 @@ func compileFilter(filter []string) (*Exp, error) {
 		if err != nil {
 			return nil, err
 		}
-		f, err := com.compileArgNode(node)
+		f, err := com.compileArgNode(node, false)
 		if err != nil {
 			return nil, err
 		}
@@ -926,3 +950,9 @@ func (t ExpOp) String() string {
 	}
 	return fmt.Sprintf("<%s>", v)
 }
+
+func FreeExp(ex *Exp) {
+	if ex.doFree {
+		expPool.Put(ex)
+	}
+}