func newSubsetLike(expr expression.BinaryFunction, re *regexp.Regexp) expression.Visitor {
if re == nil {
// Pattern is not a constant
return newSubsetDefault(expr)
}
prefix, complete := re.LiteralPrefix()
if complete {
eq := expression.NewEq(expr.First(), expression.NewConstant(prefix))
return newSubsetEq(eq.(*expression.Eq))
}
if prefix == "" {
return newSubsetDefault(expr)
}
var and expression.Expression
le := expression.NewLE(expression.NewConstant(prefix), expr.First())
last := len(prefix) - 1
if prefix[last] < math.MaxUint8 {
bytes := []byte(prefix)
bytes[last]++
and = expression.NewAnd(le, expression.NewLT(
expr.First(),
expression.NewConstant(string(bytes))))
} else {
and = expression.NewAnd(le, expression.NewLT(
expr.First(),
expression.EMPTY_ARRAY_EXPR))
}
return newSubsetAnd(and.(*expression.And))
}
func newSargLike(expr expression.BinaryFunction, re *regexp.Regexp) expression.Visitor {
prefix := ""
if re != nil {
prefix, complete := re.LiteralPrefix()
if complete {
eq := expression.NewEq(expr.First(), expression.NewConstant(prefix))
return newSargEq(eq.(*expression.Eq))
}
}
rv := &sargLike{}
rv.sarg = func(expr2 expression.Expression) (Spans, error) {
if expr.EquivalentTo(expr2) {
return _SELF_SPANS, nil
}
if !expr.First().EquivalentTo(expr2) {
return nil, nil
}
span := &Span{}
span.Range.Low = expression.Expressions{expression.NewConstant(prefix)}
last := len(prefix) - 1
if last >= 0 && prefix[last] < math.MaxUint8 {
bytes := []byte(prefix)
bytes[last]++
span.Range.High = expression.Expressions{expression.NewConstant(string(bytes))}
} else {
span.Range.High = _EMPTY_ARRAY
}
span.Range.Inclusion = datastore.LOW
return Spans{span}, nil
}
return rv
}
func constantArray(constant []interface{}) expression.Expression {
return expression.NewArrayConstruct(expression.NewConstant(value.NewValue(constant)))
}
func constant(constant interface{}) expression.Expression {
return expression.NewConstant(value.NewValue(constant))
}
}
exp = expression.NewAnd(operands...)
case *expression.Eq:
exp = expression.NewOr(expression.NewLT(operand.First(), operand.Second()),
expression.NewLT(operand.Second(), operand.First()))
case *expression.LT:
exp = expression.NewLE(operand.Second(), operand.First())
case *expression.LE:
exp = expression.NewLT(operand.Second(), operand.First())
}
return exp, exp.MapChildren(this)
}
var _EMPTY_OBJECT_EXPR = expression.NewConstant(map[string]interface{}{})
var _MIN_BINARY_EXPR = expression.NewConstant([]byte{})
func (this *NNF) VisitFunction(expr expression.Function) (interface{}, error) {
var exp expression.Expression = expr
switch expr := expr.(type) {
case *expression.IsBoolean:
exp = expression.NewLE(expr.Operand(), expression.TRUE_EXPR)
case *expression.IsNumber:
exp = expression.NewAnd(
expression.NewGT(expr.Operand(), expression.TRUE_EXPR),
expression.NewLT(expr.Operand(), expression.EMPTY_STRING_EXPR))
case *expression.IsString:
exp = expression.NewAnd(
expression.NewGE(expr.Operand(), expression.EMPTY_STRING_EXPR),
func (this *builder) selectScan(keyspace datastore.Keyspace,
node *algebra.KeyspaceTerm) (Operator, error) {
if this.where == nil {
return this.selectPrimaryScan(keyspace, node)
}
nnf := planner.NewNNF()
where := this.where.Copy()
where, err := nnf.Map(where)
if err != nil {
return nil, err
}
formalizer := expression.NewFormalizer()
formalizer.Keyspace = node.Alias()
primaryKey := expression.NewField(
expression.NewMeta(expression.NewConstant(node.Alias())),
expression.NewFieldName("id"))
indexers, err := keyspace.Indexers()
if err != nil {
return nil, err
}
indexes := make([]datastore.Index, 0, len(indexers)*16)
primaryIndexes := make(map[datastore.Index]bool, len(indexers)*2)
for _, indexer := range indexers {
idxs, err := indexer.Indexes()
if err != nil {
return nil, err
}
indexes = append(indexes, idxs...)
primaryIdxs, err := indexer.PrimaryIndexes()
if err != nil {
return nil, err
}
for _, p := range primaryIdxs {
primaryIndexes[p] = true
}
}
unfiltered := make(map[datastore.Index]expression.Expression, len(indexes))
filtered := make(map[datastore.Index]expression.Expression, len(indexes))
for _, index := range indexes {
state, _, er := index.State()
if er != nil {
return nil, er
}
if state != datastore.ONLINE {
continue
}
var key expression.Expression
if primaryIndexes[index] {
key = primaryKey
} else {
rangeKey := index.RangeKey()
if len(rangeKey) == 0 || rangeKey[0] == nil {
// Index not rangeable
continue
}
key := rangeKey[0].Copy()
key, err = formalizer.Map(key)
if err != nil {
return nil, err
}
key, err = nnf.Map(key)
if err != nil {
return nil, err
}
}
if !planner.SargableFor(where, key) {
// Index not applicable
continue
}
indexCond := index.Condition()
if indexCond == nil {
unfiltered[index] = key
continue
}
indexCond = indexCond.Copy()
indexCond, err = formalizer.Map(indexCond)
if err != nil {
return nil, err
}
indexCond, err = nnf.Map(indexCond)
if err != nil {
return nil, err
}
if planner.SubsetOf(where, indexCond) {
// Index condition satisfies query condition
filtered[index] = key
break
}
}
var indexMap map[datastore.Index]expression.Expression
if len(filtered) > 0 {
indexMap = filtered
} else if len(unfiltered) > 0 {
indexMap = unfiltered
}
for index, key := range indexMap {
spans := planner.SargFor(where, key)
var scan Operator
scan = NewIndexScan(index, node, spans, false, math.MaxInt64)
if len(spans) > 1 {
// Use UnionScan to de-dup multiple spans
scan = NewUnionScan(scan)
}
return scan, err
}
return this.selectPrimaryScan(keyspace, node)
}
