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Replace one regex by pool of regex matchers. #557

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Nov 28, 2018
Merged

Replace one regex by pool of regex matchers. #557

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74 changes: 56 additions & 18 deletions sql/expression/comparison.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@ package expression

import (
"fmt"
"sync"

errors "gopkg.in/src-d/go-errors.v1"
"gopkg.in/src-d/go-mysql-server.v0/internal/regex"
Expand Down Expand Up @@ -178,12 +179,25 @@ func (e *Equals) String() string {
// Regexp is a comparison that checks an expression matches a regexp.
type Regexp struct {
comparison
r regex.Matcher
pool *sync.Pool
cached bool
}

// NewRegexp creates a new Regexp expression.
func NewRegexp(left sql.Expression, right sql.Expression) *Regexp {
return &Regexp{newComparison(left, right), nil}
var cached = true
Inspect(right, func(e sql.Expression) bool {
if _, ok := e.(*GetField); ok {
cached = false
}
return true
})

return &Regexp{
comparison: newComparison(left, right),
pool: nil,
cached: cached,
}
}

// Eval implements the Expression interface.
Expand All @@ -205,33 +219,57 @@ func (re *Regexp) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
}

func (re *Regexp) compareRegexp(ctx *sql.Context, row sql.Row) (interface{}, error) {
left, right, err := re.evalLeftAndRight(ctx, row)
if err != nil {
left, err := re.Left().Eval(ctx, row)
if err != nil || left == nil {
return nil, err
}

if left == nil || right == nil {
return nil, nil
}

left, err = sql.Text.Convert(left)
if err != nil {
return nil, err
}

right, err = sql.Text.Convert(right)
if err != nil {
return nil, err
}

if re.r == nil {
re.r, err = regex.New(regex.Default(), right.(string))
var (
matcher regex.Matcher
right interface{}
)
// eval right and convert to text
if !re.cached || re.pool == nil {
right, err = re.Right().Eval(ctx, row)
if err != nil || right == nil {
return nil, err
}
right, err = sql.Text.Convert(right)
if err != nil {
return false, err
return nil, err
}
}
// for non-cached regex every time create a new matcher
if !re.cached {
matcher, err = regex.New(regex.Default(), right.(string))
} else {
if re.pool == nil {
re.pool = &sync.Pool{
New: func() interface{} {
r, e := regex.New(regex.Default(), right.(string))
if e != nil {
err = e
return nil
}
return r
},
}
}
matcher = re.pool.Get().(regex.Matcher)
}
if matcher == nil {
return nil, err
}

return re.r.Match(left.(string)), nil
ok := matcher.Match(left.(string))
if re.pool != nil && re.cached {
re.pool.Put(matcher)
}
return ok, nil
}

// TransformUp implements the Expression interface.
Expand Down
76 changes: 49 additions & 27 deletions sql/expression/like.go
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@ import (
"fmt"
"regexp"
"strings"
"sync"

"gopkg.in/src-d/go-mysql-server.v0/internal/regex"
"gopkg.in/src-d/go-mysql-server.v0/sql"
Expand All @@ -13,21 +14,25 @@ import (
// Like performs pattern matching against two strings.
type Like struct {
BinaryExpression
canCacheRegex bool
regex regex.Matcher
pool *sync.Pool
cached bool
}

// NewLike creates a new LIKE expression.
func NewLike(left, right sql.Expression) sql.Expression {
var canCacheRegex = true
var cached = true
Inspect(right, func(e sql.Expression) bool {
if _, ok := e.(*GetField); ok {
canCacheRegex = false
cached = false
}
return true
})

return &Like{BinaryExpression{left, right}, canCacheRegex, nil}
return &Like{
BinaryExpression: BinaryExpression{left, right},
pool: nil,
cached: cached,
}
}

// Type implements the sql.Expression interface.
Expand All @@ -38,41 +43,58 @@ func (l *Like) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
span, ctx := ctx.Span("expression.Like")
defer span.Finish()

var re regex.Matcher
if l.regex == nil {
left, err := l.Left.Eval(ctx, row)
if err != nil || left == nil {
return nil, err
}
left, err = sql.Text.Convert(left)
if err != nil {
return nil, err
}

var (
matcher regex.Matcher
right string
)
// eval right and convert to text
if !l.cached || l.pool == nil {
v, err := l.Right.Eval(ctx, row)
if err != nil {
if err != nil || v == nil {
return nil, err
}

v, err = sql.Text.Convert(v)
if err != nil {
return nil, err
}

re, err = regex.New(regex.Default(), patternToRegex(v.(string)))
if err != nil {
return nil, err
}

if l.canCacheRegex {
l.regex = re
}
right = patternToRegex(v.(string))
}
// for non-cached regex every time create a new matcher
if !l.cached {
matcher, err = regex.New(regex.Default(), right)
} else {
re = l.regex
if l.pool == nil {
l.pool = &sync.Pool{
New: func() interface{} {
r, e := regex.New(regex.Default(), right)
if e != nil {
err = e
return nil
}
return r
},
}
}
matcher = l.pool.Get().(regex.Matcher)
}

value, err := l.Left.Eval(ctx, row)
if err != nil {
if matcher == nil {
return nil, err
}

value, err = sql.Text.Convert(value)
if err != nil {
return nil, err
ok := matcher.Match(left.(string))
if l.pool != nil && l.cached {
l.pool.Put(matcher)
}

return re.Match(value.(string)), nil
return ok, nil
}

func (l *Like) String() string {
Expand Down