/
filter.go
352 lines (297 loc) 路 7.59 KB
/
filter.go
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package physicalplan
import (
"context"
"errors"
"fmt"
"regexp"
"github.com/RoaringBitmap/roaring"
"github.com/apache/arrow/go/v16/arrow"
"github.com/apache/arrow/go/v16/arrow/array"
"github.com/apache/arrow/go/v16/arrow/memory"
"github.com/apache/arrow/go/v16/arrow/scalar"
"go.opentelemetry.io/otel/trace"
"github.com/polarsignals/frostdb/query/logicalplan"
)
type PredicateFilter struct {
pool memory.Allocator
tracer trace.Tracer
filterExpr BooleanExpression
next PhysicalPlan
}
func (f *PredicateFilter) Draw() *Diagram {
var child *Diagram
if f.next != nil {
child = f.next.Draw()
}
details := fmt.Sprintf("PredicateFilter (%s)", f.filterExpr.String())
return &Diagram{Details: details, Child: child}
}
type Bitmap = roaring.Bitmap
func NewBitmap() *Bitmap {
return roaring.New()
}
type BooleanExpression interface {
Eval(r arrow.Record) (*Bitmap, error)
String() string
}
var ErrUnsupportedBooleanExpression = errors.New("unsupported boolean expression")
type ArrayReference struct{}
type PreExprVisitorFunc func(expr logicalplan.Expr) bool
func (f PreExprVisitorFunc) PreVisit(expr logicalplan.Expr) bool {
return f(expr)
}
func (f PreExprVisitorFunc) Visit(_ logicalplan.Expr) bool {
return false
}
func (f PreExprVisitorFunc) PostVisit(_ logicalplan.Expr) bool {
return false
}
func binaryBooleanExpr(expr *logicalplan.BinaryExpr) (BooleanExpression, error) {
switch expr.Op {
case logicalplan.OpEq,
logicalplan.OpNotEq,
logicalplan.OpLt,
logicalplan.OpLtEq,
logicalplan.OpGt,
logicalplan.OpGtEq,
logicalplan.OpRegexMatch,
logicalplan.OpRegexNotMatch,
logicalplan.OpAdd,
logicalplan.OpSub,
logicalplan.OpMul,
logicalplan.OpDiv,
logicalplan.OpContains,
logicalplan.OpNotContains:
var leftColumnRef *ArrayRef
expr.Left.Accept(PreExprVisitorFunc(func(expr logicalplan.Expr) bool {
switch e := expr.(type) {
case *logicalplan.Column:
leftColumnRef = &ArrayRef{
ColumnName: e.ColumnName,
}
return false
}
return true
}))
if leftColumnRef == nil {
return nil, errors.New("left side of binary expression must be a column")
}
var rightScalar scalar.Scalar
expr.Right.Accept(PreExprVisitorFunc(func(expr logicalplan.Expr) bool {
switch e := expr.(type) {
case *logicalplan.LiteralExpr:
rightScalar = e.Value
return false
}
return true
}))
switch expr.Op {
case logicalplan.OpRegexMatch:
regexp, err := regexp.Compile(string(rightScalar.(*scalar.String).Data()))
if err != nil {
return nil, err
}
return &RegExpFilter{
left: leftColumnRef,
right: regexp,
}, nil
case logicalplan.OpRegexNotMatch:
regexp, err := regexp.Compile(string(rightScalar.(*scalar.String).Data()))
if err != nil {
return nil, err
}
return &RegExpFilter{
left: leftColumnRef,
right: regexp,
notMatch: true,
}, nil
}
return &BinaryScalarExpr{
Left: leftColumnRef,
Op: expr.Op,
Right: rightScalar,
}, nil
case logicalplan.OpAnd:
left, err := booleanExpr(expr.Left)
if err != nil {
return nil, fmt.Errorf("left bool expr: %w", err)
}
right, err := booleanExpr(expr.Right)
if err != nil {
return nil, fmt.Errorf("right bool expr: %w", err)
}
return &AndExpr{
Left: left,
Right: right,
}, nil
case logicalplan.OpOr:
left, err := booleanExpr(expr.Left)
if err != nil {
return nil, fmt.Errorf("left bool expr: %w", err)
}
right, err := booleanExpr(expr.Right)
if err != nil {
return nil, fmt.Errorf("right bool expr: %w", err)
}
return &OrExpr{
Left: left,
Right: right,
}, nil
default:
return nil, fmt.Errorf("binary expr %s: %w", expr.Op.String(), ErrUnsupportedBooleanExpression)
}
}
type AndExpr struct {
Left BooleanExpression
Right BooleanExpression
}
func (a *AndExpr) Eval(r arrow.Record) (*Bitmap, error) {
left, err := a.Left.Eval(r)
if err != nil {
return nil, err
}
if left.IsEmpty() {
return left, nil
}
right, err := a.Right.Eval(r)
if err != nil {
return nil, err
}
// This stores the result in place to avoid allocations.
left.And(right)
return left, nil
}
func (a *AndExpr) String() string {
return "(" + a.Left.String() + " AND " + a.Right.String() + ")"
}
type OrExpr struct {
Left BooleanExpression
Right BooleanExpression
}
func (a *OrExpr) Eval(r arrow.Record) (*Bitmap, error) {
left, err := a.Left.Eval(r)
if err != nil {
return nil, err
}
right, err := a.Right.Eval(r)
if err != nil {
return nil, err
}
// This stores the result in place to avoid allocations.
left.Or(right)
return left, nil
}
func (a *OrExpr) String() string {
return "(" + a.Left.String() + " OR " + a.Right.String() + ")"
}
func booleanExpr(expr logicalplan.Expr) (BooleanExpression, error) {
switch e := expr.(type) {
case *logicalplan.BinaryExpr:
return binaryBooleanExpr(e)
default:
return nil, ErrUnsupportedBooleanExpression
}
}
func Filter(pool memory.Allocator, tracer trace.Tracer, filterExpr logicalplan.Expr) (*PredicateFilter, error) {
expr, err := booleanExpr(filterExpr)
if err != nil {
return nil, fmt.Errorf("create bool expr: %w", err)
}
return newFilter(pool, tracer, expr), nil
}
func newFilter(pool memory.Allocator, tracer trace.Tracer, filterExpr BooleanExpression) *PredicateFilter {
return &PredicateFilter{
pool: pool,
tracer: tracer,
filterExpr: filterExpr,
}
}
func (f *PredicateFilter) SetNext(next PhysicalPlan) {
f.next = next
}
func (f *PredicateFilter) Close() {
f.next.Close()
}
func (f *PredicateFilter) Callback(ctx context.Context, r arrow.Record) error {
// Generates high volume of spans. Comment out if needed during development.
// ctx, span := f.tracer.Start(ctx, "PredicateFilter/Callback")
// defer span.End()
filtered, empty, err := filter(f.pool, f.filterExpr, r)
if err != nil {
return err
}
if empty {
return nil
}
defer filtered.Release()
return f.next.Callback(ctx, filtered)
}
func (f *PredicateFilter) Finish(ctx context.Context) error {
return f.next.Finish(ctx)
}
func filter(pool memory.Allocator, filterExpr BooleanExpression, ar arrow.Record) (arrow.Record, bool, error) {
bitmap, err := filterExpr.Eval(ar)
if err != nil {
return nil, true, err
}
if bitmap.IsEmpty() {
return nil, true, nil
}
indicesToKeep := bitmap.ToArray()
ranges := buildIndexRanges(indicesToKeep)
totalRows := int64(0)
recordRanges := make([]arrow.Record, len(ranges))
defer func() {
for _, r := range recordRanges {
r.Release()
}
}()
for j, r := range ranges {
recordRanges[j] = ar.NewSlice(int64(r.Start), int64(r.End))
totalRows += int64(r.End - r.Start)
}
cols := make([]arrow.Array, ar.NumCols())
defer func() {
for _, col := range cols {
col.Release()
}
}()
numRanges := len(recordRanges)
for i := range cols {
colRanges := make([]arrow.Array, 0, numRanges)
for _, rr := range recordRanges {
colRanges = append(colRanges, rr.Column(i))
}
cols[i], err = array.Concatenate(colRanges, pool)
if err != nil {
return nil, true, err
}
}
return array.NewRecord(ar.Schema(), cols, totalRows), false, nil
}
type IndexRange struct {
Start uint32
End uint32
}
// buildIndexRanges returns a set of continguous index ranges from the given indicies
// ex: [1,2,7,8,9] would return [{Start:1, End:3},{Start:7,End:10}]
func buildIndexRanges(indices []uint32) []IndexRange {
ranges := []IndexRange{}
cur := IndexRange{
Start: indices[0],
End: indices[0] + 1,
}
for _, i := range indices[1:] {
if i == cur.End {
cur.End++
} else {
ranges = append(ranges, cur)
cur = IndexRange{
Start: i,
End: i + 1,
}
}
}
ranges = append(ranges, cur)
return ranges
}