// VisitBinaryOperation swaps the right side identifier to left side if left side expression is static.
// So it can be used in index plan.
func (iev *IdentEvalVisitor) VisitBinaryOperation(binop *expression.BinaryOperation) (expression.Expression, error) {
var err error
binop.L, err = binop.L.Accept(iev)
if err != nil {
return binop, errors.Trace(err)
}
binop.R, err = binop.R.Accept(iev)
if err != nil {
return binop, errors.Trace(err)
}
if binop.L.IsStatic() {
if _, ok := binop.R.(*expression.Ident); ok {
switch binop.Op {
case opcode.EQ:
case opcode.NE:
case opcode.NullEQ:
case opcode.LT:
binop.Op = opcode.GE
case opcode.LE:
binop.Op = opcode.GT
case opcode.GE:
binop.Op = opcode.LT
case opcode.GT:
binop.Op = opcode.LE
default:
// unsupported opcode
return binop, nil
}
binop.L, binop.R = binop.R, binop.L
}
}
return binop, nil
}
func (r *TableDefaultPlan) filterBinOp(ctx context.Context, x *expression.BinaryOperation) (plan.Plan, bool, error) {
ok, name, rval, err := x.IsIdentCompareVal()
if err != nil {
return r, false, errors.Trace(err)
}
if !ok {
return r, false, nil
}
if rval == nil {
// if nil, any <, <=, >, >=, =, != operator will do nothing
// any value compared null returns null
// TODO: if we support <=> later, we must handle null
return &NullPlan{r.GetFields()}, true, nil
}
_, tn, cn := field.SplitQualifiedName(name)
t := r.T
if tn != "" && tn != t.TableName().L {
return r, false, nil
}
c := column.FindCol(t.Cols(), cn)
if c == nil {
return nil, false, errors.Errorf("No such column: %s", cn)
}
var seekVal interface{}
if seekVal, err = types.Convert(rval, &c.FieldType); err != nil {
return nil, false, errors.Trace(err)
}
spans := toSpans(x.Op, rval, seekVal)
if c.IsPKHandleColumn(r.T.Meta()) {
if r.rangeScan {
spans = filterSpans(r.spans, spans)
}
return &TableDefaultPlan{
T: r.T,
Fields: r.Fields,
rangeScan: true,
spans: spans,
}, true, nil
} else if r.rangeScan {
// Already filtered on PK handle column, should not switch to index plan.
return r, false, nil
}
ix := t.FindIndexByColName(cn)
if ix == nil { // Column cn has no index.
return r, false, nil
}
return &indexPlan{
src: t,
col: c,
unique: ix.Unique,
idxName: ix.Name.O,
idx: ix.X,
spans: spans,
}, true, nil
}
func (r *TableDefaultPlan) filterBinOp(ctx context.Context, x *expression.BinaryOperation) (plan.Plan, bool, error) {
ok, name, rval, err := x.IsIdentCompareVal()
if err != nil {
return r, false, err
}
if !ok {
return r, false, nil
}
if rval == nil {
// if nil, any <, <=, >, >=, =, != operator will do nothing
// any value compared null returns null
// TODO: if we support <=> later, we must handle null
return &NullPlan{r.GetFields()}, true, nil
}
_, tn, cn := field.SplitQualifiedName(name)
t := r.T
if tn != "" && tn != t.TableName().L {
return r, false, nil
}
c := column.FindCol(t.Cols(), cn)
if c == nil {
return nil, false, errors.Errorf("No such column: %s", cn)
}
ix := t.FindIndexByColName(cn)
if ix == nil { // Column cn has no index.
return r, false, nil
}
var seekVal interface{}
if seekVal, err = types.Convert(rval, &c.FieldType); err != nil {
return nil, false, err
}
return &indexPlan{
src: t,
col: c,
idxName: ix.Name.O,
idx: ix.X,
spans: toSpans(x.Op, rval, seekVal),
}, true, nil
}