cache index exprs

Author: James Cor

memory/index.go

@@ -73,6 +73,15 @@ func (idx *Index) Expressions() []string {
 	return exprs
 }
 
+func (idx *Index) UnqualifiedExpressions() []string {
+	exprs := make([]string, len(idx.Exprs))
+	for i, e := range idx.Exprs {
+		str := e.String()
+		exprs[i] = str[strings.IndexByte(str, '.')+1:]
+	}
+	return exprs
+}
+
 func (idx *Index) ExtendedExpressions() []string {
 	var exprs []string
 	foundCols := make(map[string]struct{})

sql/analyzer/index_analyzer_test.go

@@ -15,6 +15,7 @@
 package analyzer
 
 import (
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -142,6 +143,15 @@ func (i dummyIdx) Expressions() []string {
 	}
 	return exprs
 }
+
+func (i dummyIdx) UnqualifiedExpressions() []string {
+	exprs := make([]string, len(i.expr))
+	for i, e := range i.expr {
+		str := e.String()
+		exprs[i] = str[strings.IndexByte(str, '.')+1:]
+	}
+	return exprs
+}
 func (i *dummyIdx) ID() string                            { return i.id }
 func (i *dummyIdx) Database() string                      { return i.database }
 func (i *dummyIdx) Table() string                         { return i.table }

sql/index.go

@@ -102,6 +102,8 @@ type Index interface {
 	// one expression, it means the index has multiple columns indexed. If it's
 	// just one, it means it may be an expression or a column.
 	Expressions() []string
+	// UnqualifiedExpressions returns the indexed expressions without the source.
+	UnqualifiedExpressions() []string
 	// IsUnique returns whether this index is unique
 	IsUnique() bool
 	// IsSpatial returns whether this index is a spatial index

sql/index_builder_test.go

@@ -188,6 +188,14 @@ func (i testIndex) Expressions() []string {
 	return res
 }
 
+func (i testIndex) UnqualifiedExpressions() []string {
+	res := make([]string, i.numcols)
+	for i := range res {
+		res[i] = fmt.Sprintf("column_%d", i)
+	}
+	return res
+}
+
 func (testIndex) IsUnique() bool {
 	return false
 }

sql/index_registry_test.go

@@ -16,6 +16,7 @@ package sql
 
 import (
 	"fmt"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -443,6 +444,16 @@ func (i dummyIdx) Expressions() []string {
 	}
 	return exprs
 }
+
+func (i dummyIdx) UnqualifiedExpressions() []string {
+	exprs := make([]string, len(i.expr))
+	for i, e := range i.expr {
+		str := e.String()
+		exprs[i] = str[strings.IndexByte(str, '.')+1:]
+	}
+	return exprs
+}
+
 func (i dummyIdx) ID() string              { return i.id }
 func (i dummyIdx) Database() string        { return i.database }
 func (i dummyIdx) Table() string           { return i.table }

sql/memo/rel_props.go

@@ -131,13 +131,11 @@ func newRelProps(rel RelExpr) *relProps {
 }
 
 // idxExprsColumns returns the column names used in an index's expressions.
-// TODO: this is unstable as long as periods in Index.Expressions()
-// identifiers are ambiguous.
+// Identifiers are ambiguous.
 func idxExprsColumns(idx sql.Index) []string {
-	columns := make([]string, len(idx.Expressions()))
-	for i, e := range idx.Expressions() {
-		parts := strings.Split(e, ".")
-		columns[i] = strings.ToLower(parts[1])
+	columns := idx.UnqualifiedExpressions()
+	for i := 0; i < len(columns); i++ {
+		columns[i] = strings.ToLower(columns[i])
 	}
 	return columns
 }

sql/memo/rel_props_test.go

@@ -217,6 +217,10 @@ func (i dummyIndex) Expressions() []string {
 	return i.cols
 }
 
+func (i dummyIndex) UnqualifiedExpressions() []string {
+	return i.cols
+}
+
 func (dummyIndex) IsUnique() bool {
 	return true
 }